New Phytol , IF:8.512 , 2019 Dec , V224 (4) : P1518-1531 doi: 10.1111/nph.16209
MUR1-mediated cell-wall fucosylation is required for freezing tolerance in Arabidopsis thaliana.
Department of Biosciences & Durham Centre for Crop Improvement Technology, Durham University, South Road, Durham, DH1 3LE, UK.; Scion, 49 Sala Street, Private Bag 3020, Rotorua, 3046, New Zealand.; Institute of Molecular Plant Sciences, The University of Edinburgh, Daniel Rutherford Building, The King's Buildings, Max Born Crescent, Edinburgh, EH9 3BF, UK.
Forward genetic screens play a key role in the identification of genes contributing to plant stress tolerance. Using a screen for freezing sensitivity, we have identified a novel freezing tolerance gene, SENSITIVE-TO-FREEZING8, in Arabidopsis thaliana. We identified SFR8 using recombination-based mapping and whole-genome sequencing. As SFR8 was predicted to have an effect on cell wall composition, we used GC-MS and polyacrylamide gel electrophoresis to measure cell-wall fucose and boron (B)-dependent dimerization of the cell-wall pectic domain rhamnogalacturonan II (RGII) in planta. After treatments to promote borate-bridging of RGII, we assessed freeze-induced damage in wild-type and sfr8 plants by measuring electrolyte leakage from freeze-thawed leaf discs. We mapped the sfr8 mutation to MUR1, a gene encoding the fucose biosynthetic enzyme GDP-d-mannose-4,6-dehydratase. sfr8 cell walls exhibited low cell-wall fucose levels and reduced RGII bridging. Freezing sensitivity of sfr8 mutants was ameliorated by B supplementation, which can restore RGII dimerization. B transport mutants with reduced RGII dimerization were also freezing-sensitive. Our research identifies a role for the structure and composition of the plant primary cell wall in determining basal plant freezing tolerance and highlights the specific importance of fucosylation, most likely through its effect on the ability of RGII pectin to dimerize.
PMID: 31549420
J Integr Plant Biol , IF:4.885 , 2019 Dec , V61 (12) : P1194-1200 doi: 10.1111/jipb.12800
OsCIPK7 point-mutation leads to conformation and kinase-activity change for sensing cold response.
Key Laboratory of Plant Molecular Physiology, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China.; University of Chinese Academy of Sciences, Beijing, 100049, China.; Laboratory of Soft Matter Physics, Institute of Physics, the Chinese Academy of Sciences, Beijing, 100190, China.; State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Calcineurin B-like interacting protein kinases (CIPKs) play important roles via environmental stress. However, less is known how to sense the stress in molecular structure conformation level. Here, an OsCIPK7 mutant via TILLING procedure with a point mutation in the kinase domain showed increased chilling tolerance, which could be potentially used in the molecular breeding. We found that this point mutation of OsCIPK7 led to a conformational change in the activation loop of the kinase domain, subsequently with an increase of protein kinase activity, thus conferred an increased tolerance to chilling stress.
PMID: 30912264
Int J Mol Sci , IF:4.556 , 2019 Dec , V21 (1) doi: 10.3390/ijms21010110
Identification and Functional Analysis of Tomato CIPK Gene Family.
College of Life Sciences, Northeast Agricultural University, Harbin 150030, China.; College of Plant Protection, China Agricultural University, Beijing 100000, China.; College of Arts and Sciences, Northeast Agricultural University, Harbin 150030, China.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China.; College of Sciences, Northeast Agricultural University, Harbin 150030, China.
The calcineurin B-like interacting protein kinase (CIPK) protein family is a critical protein family in plant signaling pathways mediated by Ca(2+), playing a pivotal role in plant stress response and growth. However, to the best of our knowledge, no study of the tomato CIPK gene family in response to abiotic stress has been reported. In this study, 22 members of the tomato CIPK gene family were successfully identified by using a combination of bioinformatics techniques and molecular analyses. The expression level of each member of tomato CIPK gene family under abiotic stress (low temperature, high salt, drought treatment) was determined by qRT-PCR. Results indicated that tomato CIPK demonstrated different degrees of responding to various abiotic stresses, and changes in SlCIPK1 and SlCIPK8 expression level were relatively apparent. The results of qRT-PCR showed that expression levels of SlCIPK1 increased significantly in early stages of cold stress, and the expression level of SlCIPK8 increased significantly during the three treatments at different time points, implicating Solanum lycopersicum CIPK1(SlCIPK1) and Solanum lycopersicum CIPK8 (SlCIPK8) involvement in abiotic stress response. SlCIPK1 and SlCIPK8 were silenced using Virus-induced gene silencing (VIGS), and physiological indexes were detected by low temperature, drought, and high salt treatment. The results showed that plants silenced by SlCIPK1 and SlCIPK8 at the later stage of cold stress were significantly less resistant to cold than wild-type plants. SlCIPK1 and SlCIPK8 silenced plants had poor drought resistance, indicating a relationship between SlCIPK1 and SlCIPK8 with response to low temperature and drought resistance. This is the first study to uncover the nucleotide sequence for tomato CIPK family members and systematically study the changes of tomato CIPK family members under abiotic stress. Here, we investigate the CIPK family's response under abiotic stress providing understanding into the signal transduction pathway. This study provides a theoretical basis for elucidating the function of tomato CIPK at low temperature and its molecular mechanism of regulating low temperatures.
PMID: 31877938
Int J Mol Sci , IF:4.556 , 2019 Dec , V21 (1) doi: 10.3390/ijms21010026
CaDHN4, a Salt and Cold Stress-Responsive Dehydrin Gene from Pepper Decreases Abscisic Acid Sensitivity in Arabidopsis.
College of Horticulture, Northwest A&F University, Yangling 712100, China.
Dehydrins play an important role in improving plant resistance to abiotic stresses. In this study, we isolated a dehydrin gene from pepper (Capsicum annuum L.) leaves, designated as CaDHN4. Sub-cellular localization of CaDHN4 was to be found in the nucleus and membrane. To authenticate the function of CaDHN4 in cold- and salt-stress responses and abscisic acid (ABA) sensitivity, we reduced the CaDHN4 expression using virus-induced gene silencing (VIGS), and overexpressed the CaDHN4 in Arabidopsis. We found that silencing of CaDHN4 reduced the growth of pepper seedlings and CaDHN4-silenced plants exhibited more serious wilting, higher electrolyte leakage, and more accumulation of ROS in the leaves compared to pTRV2:00 plants after cold stress, and lower chlorophyll contents and higher electrolyte leakage compared to pTRV2:00 plants under salt stress. However, CaDHN4-overexpressing Arabidopsis plants had higher seed germination rates and post-germination primary root growth, compared to WT plants under salt stress. In response to cold and salt stresses, the CaDHN4-overexpressed Arabidopsis exhibited lower MDA content, and lower relative electrolyte leakage compared to the WT plants. Under ABA treatments, the fresh weight and germination rates of transgenic plants were higher than WT plants. The transgenic Arabidopsis expressing a CaDHN4 promoter displayed a more intense GUS staining than the normal growth conditions under treatment with hormones including ABA, methyl jasmonate (MeJA), and salicylic acid (SA). Our results suggest that CaDHN4 can protect against cold and salt stresses and decrease ABA sensitivity in Arabidopsis.
PMID: 31861623
Physiol Plant , IF:4.148 , 2019 Dec , V167 (4) : P516-525 doi: 10.1111/ppl.12965
The role of HD-Zip class I transcription factors in plant response to abiotic stresses.
Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, 310018, China.; Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA.
Abiotic stresses usually affect plant growth and development, indirectly or directly causing crop production reduction and even plant death. To survive, plants utilize different mechanisms to adapt themselves to continuously changing surrounding environmental stresses. Homeodomain-leucine zipper (HD-Zip) transcription factors are unique to the plant kingdom and divided into four different subfamilies (HD-Zip I approximately IV). Many HD-Zip I members have been shown to play critical roles in the regulation of plant developmental processes, signaling networks and responses to environmental stresses. This review focuses on the role of HD-Zip I transcription factors in plant responses to various abiotic stresses, including abscisic acid-mediated stress, drought and cold stress, oxidative stress, helping to identify the potential regulatory mechanisms that alleviate abiotic stress in plants.
PMID: 30851063
Physiol Plant , IF:4.148 , 2019 Dec , V167 (4) : P502-515 doi: 10.1111/ppl.12903
Overexpression of transketolase gene promotes chilling tolerance by increasing the activities of photosynthetic enzymes, alleviating oxidative damage and stabilizing cell structure in Cucumis sativus L.
StateKey Laboratory of Crop Biology/Key Laboratory of Crop Biology and Genetic Improvement of Horticultural Crops in Huanghuai Region/College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong, 271018, China.
Despite being a key enzyme of Cavin cycle, transketolase (TK) is believed to be related to abiotic resistance in higher plants. However, how TK affects chilling tolerance still remains largely unknown. Here, we describe the effect of overexpression of the Cucumis sativa TK gene (CsTK) on growth, photosynthesis, ROS metabolism and cell ultrastructure under chilling stress. Low temperature led to a decrease of the photosynthetic rate (Pn), the stomatal conductance (Gs), the actual photochemical efficiency (PhiPSII) and the sucrose content, whereas there was an increase of the intercellular CO2 concentration (Ci) and MDA content. These changes were alleviated in the CsTK plants after 5 days of chilling stress, however, inhibition of CsTK showed the opposite results. Furthermore, transgenic plants with overexpression of CsTK showed higher increase in leaf area and dry matter, higher activity of the enzymes and higher increase in the contents of metabolism substance involved in Calvin cycle and reactive oxygen scavenging system as well as lower (*) OH and H2 O2 content, superoxide anion production rate compared with the control cucumber plants under chilling stress. At the end of the chilling stress, compared to wild-type (WT) which exhibited dramatically destroyed cell ultrastructure, expanded chloroplast, broken cell and chloroplast membranes as well as the disappeared grana lamella, the CsTK sense plants showed a more complete cell ultrastructure, whereas, the damage of the cell ultrastructure was aggravated in CsTK antisense plants. Taken together, these results imply that CsTK promoted chilling tolerance in cucumber plants mainly through increasing the capacity to assimilate carbon, alleviating oxidative damage and stabilizing cell structure.
PMID: 30548278
Plant Cell Physiol , IF:4.062 , 2019 Dec , V60 (12) : P2744-2757 doi: 10.1093/pcp/pcz162
Type II Ice-Binding Proteins Isolated from an Arctic Microalga Are Similar to Adhesin-Like Proteins and Increase Freezing Tolerance in Transgenic Plants.
Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea.; Division of Polar Life Sciences, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea.; Department of Polar Science, University of Science and Technology, Daejeon 34113, Republic of Korea.; Department of Biotechnology, Duksung Women's University, Seoul 01369, Republic of Korea.; Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea.
Microalgal ice-binding proteins (IBPs) in the polar region are poorly understood at the genome-wide level, although they are important for cold adaptation. Through the transcriptome study with the Arctic green alga Chloromonas sp. KNF0032, we identified six Chloromonas IBP genes (CmIBPs), homologous with the previously reported IBPs from Antarctic snow alga CCMP681 and Antarctic Chloromonas sp. They were organized with multiple exon/intron structures and low-temperature-responsive cis-elements in their promoters and abundantly expressed at low temperature. The biological functions of three representative CmIBPs (CmIBP1, CmIBP2 and CmIBP3) were tested using in vitro analysis and transgenic plant system. CmIBP1 had the most effective ice recrystallization inhibition (IRI) activities in both in vitro and transgenic plants, and CmIBP2 and CmIBP3 had followed. All transgenic plants grown under nonacclimated condition were freezing tolerant, and especially 35S::CmIBP1 plants were most effective. After cold acclimation, only 35S::CmIBP2 plants showed slightly increased freezing tolerance. Structurally, the CmIBPs were predicted to have beta-solenoid forms with parallel beta-sheets and repeated TXT motifs. The repeated TXT structure of CmIBPs appears similar to the AidA domain-containing adhesin-like proteins from methanogens. We have shown that the AidA domain has IRI activity as CmIBPs and phylogenetic analysis also supported that the AidA domains are monophyletic with ice-binding domain of CmIBPs, and these results suggest that CmIBPs are a type of modified adhesins.
PMID: 31418793
Rice (N Y) , IF:3.912 , 2019 Dec , V12 (1) : P94 doi: 10.1186/s12284-019-0350-6
Early cold stress responses in post-meiotic anthers from tolerant and sensitive rice cultivars.
Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Ocampo y Esmeralda, Rosario, Argentina.; Department of Biosciences, Universita degli Studi di Milano, via Celoria 26, 20133, Milan, Italy.; Present address: Department of Agri-Food Engineering and Biotechnology, Barcelona School of Agricultural Engineering, UPC, Esteve Terrades 8, Building 4, 08860, Castelldefels, Spain.; Department of Biosciences, Universita degli Studi di Milano, via Celoria 26, 20133, Milan, Italy. martin.kater@unimi.it.
BACKGROUND: Rice grain production is susceptible to a changing environment that imposes both biotic and abiotic stress conditions. Cold episodes are becoming more frequent in the last years and directly affect rice yield in areas with a temperate climate. Rice is particularly susceptible to cold stress during the reproductive phase, especially in anthers during post-meiotic stages which, in turn, affect pollen production. However, a number of rice cultivars with a certain degree of tolerance to cold have been described, which may represent a good breeding resource for improvement of susceptible commercial varieties. Plants experiencing cold stress activate a molecular response in order to reprogram many metabolic pathways to face these hostile conditions. RESULTS: Here we performed RNA-seq analysis using cold-stressed post-meiotic anther samples from a cold-tolerant, Erythroceros Hokkaido (ERY), and a cold-susceptible commercial cultivar Sant'Andrea (S.AND). Both cultivars displayed an early common molecular response to cold, although the changes in expression levels are much more drastic in the tolerant one. Comparing our datasets, obtained after one-night cold stress, with other similar genome-wide studies showed very few common deregulated genes, suggesting that molecular responses in cold-stressed anthers strongly depend on conditions and the duration of the cold treatments. Cold-tolerant ERY exhibits specific molecular responses related to ethylene metabolism, which appears to be activated after cold stress. On the other hand, S.AND cold-treated plants showed a general downregulation of photosystem I and II genes, supporting a role of photosynthesis and chloroplasts in cold responses in anthers, which has remained elusive. CONCLUSIONS: Our study revealed that a number of ethylene-related transcription factors, as putative master regulators of cold responses, were upregulated in ERY providing promising candidates to confer tolerance to susceptible cultivars. Our results also suggest that the photosynthesis machinery might be a good target to improve cold tolerance in anthers. In summary, our study provides valuable candidates for further analysis and molecular breeding for cold-tolerant rice cultivars.
PMID: 31853825
Plant Cell Rep , IF:3.825 , 2019 Dec , V38 (12) : P1551-1561 doi: 10.1007/s00299-019-02466-2
Characterization of watermelon anther and its programmed cell death-associated events during dehiscence under cold stress.
Laboratory of Germplasm Innovation and Molecular Breeding, College of Agriculture and Biotechnology, Zhejiang University, No. 866 Yuhang Road, Hangzhou, 310058, People's Republic of China.; Key Laboratory of Horticultural Plant Growth, Development & Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, People's Republic of China.; Laboratory of Germplasm Innovation and Molecular Breeding, College of Agriculture and Biotechnology, Zhejiang University, No. 866 Yuhang Road, Hangzhou, 310058, People's Republic of China. mfzhang@zju.edu.cn.; Key Laboratory of Horticultural Plant Growth, Development & Quality Improvement, Ministry of Agriculture, Hangzhou, 310058, People's Republic of China. mfzhang@zju.edu.cn.
KEY MESSAGE: The 'neglected' thermophile fruit crop of watermelon was first used as a model crop to study the PCD associated with anther dehiscence in cold-exposed condition during anther development. Anther dehiscence ensures normal pollen release and successful fertilization at fruit-setting stages in flowering plants. However, most researches pertinent to anther dehiscence are centered on model plant and/or major field crops under optimal growth condition. Due to anther indehiscence in cold condition, crop plants of thermophile tropical or subtropical fruit crops fail to accomplish timely pollination and fertilization, resulting in a great yield loss annually. Herein, we developed an ideal model crop for studying the programmed cell death (PCD) associated with anther dehiscence under low-temperature stress using the S-shaped spiral anther in watermelon as instead. Our results revealed that, including the tapetal cell layers, both cells of the interlocular septum and the stomium were blocked in PCD associated with anther dehiscence at 15 degrees C. Likewise, TUNEL assays visualized the evidence that low temperature at 15 degrees C interferes with not only the PCD of tapetal cells, but also the PCD of interlocular septum and stomium. Furthermore, the expressions of genes correlated with PCD of tapetum and stomium were significantly inhibited at 15 degrees C, suggesting that low temperature affects anther dehiscence by inhibiting PCD of sporophytic tissue-related gene expressions. The findings of the current research provide mechanistic insights into anther indehiscence leading to poor fruit-setting for thermophile fruit crop such as watermelon under adverse cold condition in flowering.
PMID: 31463555
Tree Physiol , IF:3.655 , 2019 Dec , V39 (12) : P2045-2054 doi: 10.1093/treephys/tpz081
Overexpression of PtrbHLH, a basic helix-loop-helix transcription factor from Poncirus trifoliata, confers enhanced cold tolerance in pummelo (Citrus grandis) by modulation of H2O2 level via regulating a CAT gene.
Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.; Mountainous Areas Research Institute, Hebei Agricultural University, Baoding 071001, China.
The basic helix-loop-helix (bHLH) family of transcription factors (TFs) plays a crucial role in regulating plant response to abiotic stress by targeting a large spectrum of stress-responsive genes. However, the physiological mechanisms underlying the TF-mediated stress response are still poorly understood for most of the bHLH genes. In this study, transgenic pummelo (Citrus grandis) plants overexpressing PtrbHLH, a TF previously identified from Poncirus trifoliata, were generated via Agrobacterium-mediated transformation. In comparison with the wild-type plants, the transgenic lines exhibited significantly lower electrolyte leakage and malondialdehyde content after cold treatment, thereby resulting in a more tolerant phenotype. Meanwhile, the transgenic lines accumulated dramatically lower reactive oxygen species (ROS) levels, consistent with elevated activity and expression levels of antioxidant enzymes (genes), including catalase (CAT), peroxidase and superoxide dismutase. In addition, PtrbHLH was shown to specifically bind to and activate the promoter of PtrCAT gene. Taken together, these results demonstrated that overexpression of PtrbHLH leads to enhanced cold tolerance in transgenic pummelo, which may be due, at least partly, to modulation of ROS levels by regulating the CAT gene.
PMID: 31330032
BMC Genomics , IF:3.594 , 2019 Dec , V20 (1) : P989 doi: 10.1186/s12864-019-6354-1
Transcriptome analysis reveals plasticity in gene regulation due to environmental cues in Primula sikkimensis, a high altitude plant species.
National Center for Biological Sciences (NCBS), Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bengaluru, Karnataka, 560065, India. priyadarshinig@ncbs.res.in.; Manipal University, Manipal, India. priyadarshinig@ncbs.res.in.; National Center for Biological Sciences (NCBS), Tata Institute of Fundamental Research, GKVK Campus, Bellary Road, Bengaluru, Karnataka, 560065, India.; Present Address: Thapar Institute of Engineering & Technology, Department of Biotechnology, Patiala, Punjab, 147004, India.; Institute of Bioresource & Sustainable Development, A National Institute under Department of Biotechnology, Ministry of Science & Technology, Government of India, Gangtok, Sikkim, 737102, India.; Present address: Institute of Bioresources and Sustainable Development, Meghalaya, 6th Mile, Upper Shillong, Meghalaya, 793009, India.
BACKGROUND: Studying plasticity in gene expression in natural systems is crucial, for predicting and managing the effects of climate change on plant species. To understand the contribution of gene expression level variations to abiotic stress compensation in a Himalaya plant (Primula sikkimensis), we carried out a transplant experiment within (Ambient), and beyond (Below Ambient and Above Ambient) the altitudinal range limit of species. We sequenced nine transcriptomes (three each from each altitudinal range condition) using Illumina sequencing technology. We compared the fitness variation of transplants among three transplant conditions. RESULTS: A large number of significantly differentially expressed genes (DEGs) between below ambient versus ambient (109) and above ambient versus ambient (85) were identified. Transcripts involved in plant growth and development were mostly up-regulated in below ambient conditions. Transcripts involved in signalling, defence, and membrane transport were mostly up-regulated in above ambient condition. Pathway analysis revealed that most of the genes involved in metabolic processes, secondary metabolism, and flavonoid biosynthesis were differentially expressed in below ambient conditions, whereas most of the genes involved in photosynthesis and plant hormone signalling were differentially expressed in above ambient conditions. In addition, we observed higher reproductive fitness in transplant individuals at below ambient condition compared to above ambient conditions; contrary to what we expect from the cold adaptive P. sikkimensis plants. CONCLUSIONS: We reveal P. sikkimensis's capacity for rapid adaptation to climate change through transcriptome variation, which may facilitate the phenotypic plasticity observed in morphological and life history traits. The genes and pathways identified provide a genetic resource for understanding the temperature stress (both the hot and cold stress) tolerance mechanism of P. sikkimensis in their natural environment.
PMID: 31847812
Plant Sci , IF:3.591 , 2019 Dec , V289 : P110254 doi: 10.1016/j.plantsci.2019.110254
Zoysia japonica MYC type transcription factor ZjICE1 regulates cold tolerance in transgenic Arabidopsis.
Department of Biotechnology, Jeju National University, Jeju, Republic of Korea; Subtropical Horticulture Research Institute, Jeju National University, Jeju, Republic of Korea.; Subtropical Horticulture Research Institute, Jeju National University, Jeju, Republic of Korea. Electronic address: honggyu@jejunu.ac.kr.; Subtropical Horticulture Research Institute, Jeju National University, Jeju, Republic of Korea.; Department of Biotechnology, Jeju National University, Jeju, Republic of Korea.; Department of Biotechnology, Jeju National University, Jeju, Republic of Korea; Subtropical Horticulture Research Institute, Jeju National University, Jeju, Republic of Korea. Electronic address: hyoyeon@jejunu.ac.kr.
ICE1 (Inducer of CBF Expression 1) is a regulator of cold-induced transcriptome, which plays an important role in plant cold response pathway. To enhance the cold tolerance of Zoysia japonica, one of the warm-season turfgrasses, it is helpful to understand the cold response mechanism in Zoysia japonica. We identified stress-responsive ZjICE1 from Zoysia japonica and characterized its function in cold stress. Our results showed that ZjICE1 shared the typical feature of ICE homolog proteins belonging to a nucleic protein. Transactivation activity assay revealed that ZjICE1 bound to the MYC cis-element in the ZjDREB1's promotor. The ZjICE1 overexpressed transgenic Arabidopsis showed enhanced tolerance to cold stress with an increases in SOD, POD, and free proline content and reduction in MDA content. They also induced the transcripts abundance of cold-responsive genes (CBF1, CBF2, CBF3, COR47A, KIN1, and RD29A) after cold treatment. These results suggest that ZjICE1 is a positive regulator in Zoysia japonica plant during cold stress and can be a useful gene for the molecular breeding program to develop the cold tolerant zoysiagrass. Furthermore, the ZjICE1 also conferred resistance to salt and drought stresses, providing the better understanding of the basic helix-loop-helix (bHLH) gene family in abiotic stress responses.
PMID: 31623785
Plant Sci , IF:3.591 , 2019 Dec , V289 : P110246 doi: 10.1016/j.plantsci.2019.110246
A novel cold-regulated protein isolated from Saussurea involucrata confers cold and drought tolerance in transgenic tobacco (Nicotiana tabacum).
Key Laboratory of Agricultural Biotechnology, College of Life Science, Shihezi University, Shihezi 832000, China.; Key Laboratory of Agricultural Biotechnology, College of Life Science, Shihezi University, Shihezi 832000, China. Electronic address: jianboz9@sina.com.
Adverse environmental conditions, such as cold and drought, can inhibit plant growth, development, and productivity. The isolation and characterization of stress response genes from stress-tolerant plants can provide a better understanding of the underlying adaptive mechanisms. In this study, a novel cold-regulated gene, SikCOR413PM1, was isolated from Saussurea involucrata Kar. et Kir., which is a plant that survives at the high altitudes and in the low temperatures of alpine slopes in northwestern China. SikCOR413PM1 was induced in response to cold and drought in S. involucrata, and phylogenetic analysis revealed that the gene groups with a COR gene encoding a COR413PM protein family member. Subcellular localization of a SikCOR413PM1-green fluorescent fusion protein showed that SikCOR413PM1 was localized to the plasma membrane. A transgenic tobacco (Nicotiana tabacum) system was employed to investigate the possible role of SikCOR413PM1 in cold and drought tolerance. Analyses of growth, germination and survival rates, relative water content, malondialdehyde content, relative electrolyte leakage, and maximal photochemical efficiency of photosystem II showed that transgenic tobacco plants expressing SikCOR413PM1 were more tolerant to cold and drought stresses than WT plants. SikCOR413PM1 overexpression was also accompanied by constitutive activation of NtDREB1 and NtDREB3, two cold-responsive transcription factor genes, and NtERD10A and NtERD10B, two cold-induced genes. The expression levels of downstream transcription factor genes NtDREB3, NtERD10C, NtERD10D, and NtLEA5 were also induced in SikCOR413PM1-expressing transgenic plants under drought conditions. Our results suggest that the overexpression of SikCOR413PM1 induces changes in tobacco plants, and facilitates enhanced tolerance to cold and drought stresses.
PMID: 31623784
Plant Sci , IF:3.591 , 2019 Dec , V289 : P110215 doi: 10.1016/j.plantsci.2019.110215
Overexpression of 14-3-3 proteins enhances cold tolerance and increases levels of stress-responsive proteins of Arabidopsis plants.
Department of Biology, University of Rome Tor Vergata, 00133, Rome, Italy. Electronic address: visconti@uniroma2.it.; Proteomics & Mass Spectrometry Laboratory ISPAAM, National Research Council, 80147, Naples, Italy. Electronic address: chiara.dambrosio@cnr.it.; Department of Biology, University of Rome Tor Vergata, 00133, Rome, Italy.; Proteomics & Mass Spectrometry Laboratory ISPAAM, National Research Council, 80147, Naples, Italy.; Department of Biology, University of Padova, 35131, Padova, Italy.
14-3-3 proteins are a family of conserved proteins present in eukaryotes as several isoforms, playing a regulatory role in many cellular and physiological processes. In plants, 14-3-3 proteins have been reported to be involved in the response to stress conditions, such as drought, salt and cold. In the present study, 14-3-3epsilon and 14-3-3omega isoforms, which were representative of epsilon and non-epsilon phylogenetic groups, were overexpressed in Arabidopsis thaliana plants; the effect of their overexpression was investigated on H(+)-ATPase activation and plant response to cold stress. Results demonstrated that H(+)-ATPase activity was increased in 14-3-3omega-overexpressing plants, whereas overexpression of both 14-3-3 isoforms brought about cold stress tolerance, which was evaluated through ion leakage, lipid peroxidation, osmolyte synthesis, and ROS production assays. A dedicated tandem mass tag (TMT)-based proteomic analysis demonstrated that different proteins involved in the plant response to cold or oxidative stress were over-represented in 14-3-3epsilon-overexpressing plants.
PMID: 31623776
Plant Sci , IF:3.591 , 2019 Dec , V289 : P110273 doi: 10.1016/j.plantsci.2019.110273
Heat stress transcription factor OsSPL7 plays a critical role in reactive oxygen species balance and stress responses in rice.
Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 17104, South Korea.; Graduate School of Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin 17104, South Korea. Electronic address: jjeon@khu.ac.kr.
The rice spotted leaf gene, OsSPL7, induces lesion mimic (LM) spots under heat stress. Herein, we provide several lines of evidence elucidating the importance of OsSPL7 in maintaining reactive oxygen species (ROS) balance via the regulation of downstream gene expression. osspl7 knockout (spl7ko) mutants showed LM and growth retardation. Transgenic rice lines strongly overexpressing OsSPL7 (SPL7OX-S) exhibited LM accompanied by accumulated H2O2, whereas moderate expressers of OsSPL7 (SPL7OX-M) did not, and neither of them exhibited severe growth defects. Transient expression of OsSPL7-GFP in rice protoplasts indicated that OsSPL7 localizes predominantly in the nucleus. Transcriptional activity assay suggested its function as a transcriptional activator in rice. Disease evaluation showed that both SPL7OX and spl7ko enhanced resistance to Magnaporthe oryzae and Xanthomonas oryzae pv. oryzae, the causal agents of blast and blight diseases in rice, respectively. Additionally, SPL7OX enhanced tolerance to cold stress, whereas spl7ko showed a phenotype opposite to the overexpression lines. RNA sequencing analyses identified four major groups of differentially expressed genes associated with LM, pathogen resistance, LM-pathogen resistance, and potential direct targets of OsSPL7. Collectively, our results suggest that OsSPL7 plays a critical role in plant growth and balancing ROS during biotic and abiotic stress.
PMID: 31623772
Sensors (Basel) , IF:3.275 , 2019 Dec , V20 (1) doi: 10.3390/s20010062
Salt Priming Protects Photosynthetic Electron Transport against Low-Temperature-Induced Damage in Wheat.
Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Science, Changchun 130102, China.; University of Chinese Academy of Science, Beijing 100049, China.; Crop Research Institute, Shandong Academy of Agricultural Sciences, Jinan 250100, China.; Institute of Agricultural Resources and Environment, Jilin Academy of Agriculture Sciences/State Engineering Laboratory of Maize, Changchun 130033, China.; Rice Research Institute, Shandong Academy of Agricultural Science, 2 Sangyuan Road, Jinan 250100, China.; College of Life Sciences, Anhui Normal University, Wuhu 241000, China.
Low temperature limits the photochemical efficiency of photosystems in wheat plants. To test the effect of salt priming on the photosynthetic electron transport in wheat under low temperature, the germinating seeds of a winter wheat cv. Jimai44 were primed with varying concentrations of NaCl solutions (0, 10, 30, and 50 mM NaCl, indicated by S0, S10, S30, and S50, respectively) for 6 d, and after 11 d of recovery, the seedlings were subsequently exposed to 24-h low-temperature stress (2 degrees C). Under low temperature, the S30 plants possessed the highest absorption flux per reaction center and higher density of reaction center per cross-section among the treatments. In addition, S30 plants had higher trapped energy flux for reducing QA and fraction of QA-reducing reaction centers and non-QB reducing center than the non-primed plants under low temperature, indicating that S30 plants could maintain the energy balance of photosystems and a relatively higher maximum quantum efficiency of photosystem II under low temperature. In addition, the low temperature-induced MDA accumulation and cell death were alleviated by salt priming in S30 plants. It was suggested that salt priming with an optimal concentration of NaCl solution (30 mM) during seed germination enhanced the photochemical efficiency of photosystems in wheat seedlings, which could be a potential approach to improve cold tolerance in wheat at an early stage.
PMID: 31877640
G3 (Bethesda) , IF:2.781 , 2019 Dec , V9 (12) : P4045-4057 doi: 10.1534/g3.119.400353
Genetic Architecture of Chilling Tolerance in Sorghum Dissected with a Nested Association Mapping Population.
Department of Agronomy, Kansas State University, Manhattan, KS, 66506.; USDA-ARS, Plant Stress & Germplasm Development Unit, Cropping Systems Research Lab, Lubbock, TX, 79415, and.; Agricultural Research Center, Kansas State University, Hays, Kansas 67601.; Department of Agronomy, Kansas State University, Manhattan, KS, 66506, gpmorris@ksu.edu.
Dissecting the genetic architecture of stress tolerance in crops is critical to understand and improve adaptation. In temperate climates, early planting of chilling-tolerant varieties could provide longer growing seasons and drought escape, but chilling tolerance (<15 degrees ) is generally lacking in tropical-origin crops. Here we developed a nested association mapping (NAM) population to dissect the genetic architecture of early-season chilling tolerance in the tropical-origin cereal sorghum (Sorghum bicolor [L.] Moench). The NAM resource, developed from reference line BTx623 and three chilling-tolerant Chinese lines, is comprised of 771 recombinant inbred lines genotyped by sequencing at 43,320 single nucleotide polymorphisms. We phenotyped the NAM population for emergence, seedling vigor, and agronomic traits (>75,000 data points from approximately 16,000 plots) in multi-environment field trials in Kansas under natural chilling stress (sown 30-45 days early) and normal growing conditions. Joint linkage mapping with early-planted field phenotypes revealed an oligogenic architecture, with 5-10 chilling tolerance loci explaining 20-41% of variation. Surprisingly, several of the major chilling tolerance loci co-localize precisely with the classical grain tannin (Tan1 and Tan2) and dwarfing genes (Dw1 and Dw3) that were under strong directional selection in the US during the 20(th) century. These findings suggest that chilling sensitivity was inadvertently selected due to coinheritance with desired nontannin and dwarfing alleles. The characterization of genetic architecture with NAM reveals why past chilling tolerance breeding was stymied and provides a path for genomics-enabled breeding of chilling tolerance.
PMID: 31611346
Plants (Basel) , IF:2.762 , 2019 Dec , V8 (12) doi: 10.3390/plants8120588
Seed Pretreatment and Foliar Application of Proline Regulate Morphological, Physio-Biochemical Processes and Activity of Antioxidant Enzymes in Plants of Two Cultivars of Quinoa (Chenopodium quinoa Willd.).
Department of Botany, Government College University, Faisalabad 38040, Pakistan.; University of Agriculture, Faisalabad 38040, Pakistan.; Botany and Microbiology Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia.; Department of Botany, S.P. College, Srinagar 190001, Jammu and Kashmir, India.
In the current study, the effects of exogenously applied proline (25 and 50 mM) and low-temperature treatment were examined on the physiochemical parameters in the plants of two cultivars (V1 and V2) of quinoa (Chenopodium quinoa Willd.). The seeds were also exposed to chilling stress at 4 degrees C before sowing. Plants raised from the seeds treated with low temperature showed reduced plant growth and contents of chlorophyll and carotenoids, but they had significantly increased contents of malondialdehyde, proline, ascorbic acid, total free amino acids, total soluble sugars, and total phenolics, as well as the activity of the peroxidase (POD) enzyme. Cold stress applied to seeds remained almost ineffective in terms of bringing about changes in plant root, hydrogen peroxide, glycine betaine and activities of superoxide dismutase (SOD), and catalase (CAT) enzymes. The exogenous application of proline significantly increased plant growth, the contents of chlorophyll, carotenoids, proline, ascorbic acid, total free amino acids, phenolics, and total soluble sugars, as well as the activities of SOD, POD, and CAT, but it decreased malondialdehyde content. Overall, foliar application of proline was better than the seed treatment in improving root dry weight, root length, chlorophyll a, carotenoids, glycine betaine, ascorbic acid and superoxide dismutase activity, whereas seed pre-treatment with proline was effective in improving shoot dry weight, shoot length, hydrogen peroxide, malondialdehyde, and peroxidase activity in both quinoa cultivars.
PMID: 31835633
Int J Biometeorol , IF:2.68 , 2019 Dec , V63 (12) : P1597-1609 doi: 10.1007/s00484-019-01772-4
Assessing multi-risk characteristics of heat and cold stress for rice across the southern parts of China.
National Meteorological Center, Beijing, 100081, China.; National Satellite Meteorological Center, Beijing, 100081, China.; National Climate Center, Beijing, 100081, China.; Chinese Academy of Meteorological Sciences, Beijing, 100081, China. huozg@cma.gov.cn.; Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Nanjing University of Information Science & Technology, Nanjing, 210044, China. huozg@cma.gov.cn.
Rice (Oryza sativa) growth is always threatened by heat as well as cold stress, when it is exposed to natural environment. Heat growing degree hours (HGDH) and cold growing degree hours (CGDH1 and CGDH2) were firstly proposed to quantify heat and cold stress occurred during different growing stages. Information diffusion method was effectively used to fit the distribution and estimate probability of single stress at each station, with an advantage of no limitation in data series. In terms of single stress, highest probability was seen in HGDH, followed by CGDH1 and CGDH2. Seven copula functions, i.e., normal and t, Gumbel-Hougaard, Clayton, Frank, Joe, and Ali-Mikhail-Haq, were applied to fit the distribution of multi-stress with significant dependence, and simple calculation based on single stress was used to quantify the probability for multi-stress with independence. In these copulas, t was the most chosen one in the fitting of HGDH-CGDH1, HGDH-CGDH2, CGDH1-CGDH2, and HGDH-CGDH1-CGDH2, selected by the statistic of Akaike information criterion. Regarding bi-stress, higher joint probability was in HGDH-CGDH1, relative to HGDH-CGDH2 and CGDH1-CGDH2. As expected, the co-occurrence probability of tri-stress was lower than that of bi-stress in the magnitude and spatial extent, while joint probability of tri-stress was larger. Given the condition of occurrence of HGDH or CGDH1, the joint probability of HGDH-CGDH1 was higher than other pairs of bi-stress and tri-stress. It was special that higher joint probability of CGDH1-CGDH2 was detected under the condition of CGDH2 relative to CGDH1. Joint probability of tri-stress was lower under the condition of HGDH-CGDH1, in comparison with HGDH-CGDH2 and CGDH1-CGDH2. Hazards of single stress and multi-stress were expressed by the integration of intensity of stress index and corresponding probability. Most consistent conclusions agreed that central Fujian, Zhejiang, and northeastern Jiangxi were exposed to higher hazard, derived from not only single stress but also multi-stress. These results can be helpful in provision of information regarding prevention and adaptation strategies for rice cultivation as a response to extreme temperature stress.
PMID: 31414185
J Sci Food Agric , IF:2.614 , 2019 Dec , V99 (15) : P6868-6881 doi: 10.1002/jsfa.9972
Comparative metabolites profiling of harvested papaya (Carica papaya L.) peel in response to chilling stress.
Key Laboratory of Plant Resources Conservation and Sustainable Utilization, Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, School of Life Sciences, Guangzhou, P. R. China.; University of Chinese Academy of Sciences, School of Life Sciences, Beijing, P. R. China.; Key Laboratory of Post-Harvest Handling of Fruits, Ministry of Agriculture, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, P. R. China.
BACKGROUND: Papaya, as one of the most important tropical fruits in the world, is easily subjected to chilling injury (CI). Research on the effect of chilling temperature storage on the metabolic changes of papaya peel is limited. RESULTS: Chilling temperature (4 degrees C) inhibited fruit ripening and induced CI on papaya fruit. Additionally, low temperature altered the concentrations of 45 primary metabolites and 52 aroma volatile compounds in the papaya peel. Papaya fruit stored at different temperatures could be separated using partial least squares-discriminant analysis (PLS-DA) with primary metabolites and volatile compounds as variables. In total, 18 primary metabolites and 22 volatiles with variable importance in projection (VIP) score higher than one might be considered as potential markers in papaya peel in response to chilling stress. Metabolites related to aroma, such as organic acid, amino acids, hexanal, carbonic acid, pentadecyl propyl ester and methyl geranate, caryophyllene accounted for major part of the metabolism changes of papaya peel and contributed a lot in response to cold stress. CONCLUSION: This study added new insights regarding effect of chilling stress on metabolites in papaya peel. Some important metabolites might be indicator for chilling stress and detection of these metabolites will guide us to regulate the storage temperature to avoid chilling and to prolong storage of papaya fruit. (c) 2019 Society of Chemical Industry.
PMID: 31386200
BMC Immunol , IF:2.495 , 2019 Dec , V20 (1) : P49 doi: 10.1186/s12865-019-0331-y
Amentoflavone ameliorates cold stress-induced inflammation in lung by suppression of C3/BCR/NF-kappaB pathways.
School of Life Sciences and Biopharmaceutis, Shenyang Pharmaceutical University, Shenyang, 110016, China. caijiayi_syphu@163.com.; Department of Pharmacy, General Hospital of Northern Theater Command, Shenyang, 110840, China. caijiayi_syphu@163.com.; College of Pharmaceutical Science, China Medical University, Shenyang, 110122, China. caijiayi_syphu@163.com.; College of Pharmaceutical Science, China Medical University, Shenyang, 110122, China.; Department of Pharmacy, the First Affiliated Hospital of China Medical University, Shenyang, 110001, China.; School of Life Sciences and Biopharmaceutis, Shenyang Pharmaceutical University, Shenyang, 110016, China.; Department of Pharmacy, General Hospital of Northern Theater Command, Shenyang, 110840, China.; School of Life Sciences and Biopharmaceutis, Shenyang Pharmaceutical University, Shenyang, 110016, China. zhaoqingchun1967@163.com.; Department of Pharmacy, General Hospital of Northern Theater Command, Shenyang, 110840, China. zhaoqingchun1967@163.com.
BACKGROUND: Cold stress, which may lead to local and systemic injury, is reported to be related to the immune system, especially the complement system. At present, the lack of effective treatment is a critical issue. Amentoflavone (AF), which can inhibit cold stress-induced inflammation in lung by multiple mechanisms, is the main therapeutic ingredient in plants of the genus Selaginella. RESULTS: In the current study, we found that cold could induce lung inflammation related to the complement system and its downstream pathways. AF treatment significantly inhibited lung inflammation from cold exposure. We presented evidence that AF can bind to complement component 3 (C3) to regulate inflammation-related pathways involving Lck/Yes novel tyrosine kinase (Lyn), protein kinase B (Akt), nuclear factor-kappaB (NF-kappaB) and immune factors. Moreover, 30 mg/kg of AF caused significantly greater improvement than 15 mg/kg in reducing the level of C3 in lung tissue. CONCLUSIONS: AF can protect lung tissue from cold exposure. The protective effect may be achieved by inhibition of C3 and negative regulation of the B cell receptor (BCR)/NF-kappaB signaling pathways and high mobility group box 1 (HMGB1), which ultimately ameliorates the inflammatory response.
PMID: 31888465
Cryobiology , IF:2.283 , 2019 Dec , V91 : P97-103 doi: 10.1016/j.cryobiol.2019.10.003
Exogenous carnitine application augments transport of fatty acids into mitochondria and stimulates mitochondrial respiration in maize seedlings grown under normal and cold conditions.
East Anatolian High Technology Application and Research Center, Ataturk University, Erzurum, Turkey; Department of Biology, Science Faculty, Ataturk University, 25240, Erzurum, Turkey. Electronic address: hulyaa.turk@hotmail.com.; H. Avni Ulas Mah, Sabuncu Sok, Palandoken, 25070, Erzurum, Turkey.; Department of Biology, Science Faculty, Ataturk University, 25240, Erzurum, Turkey.
This study aimed to investigate whether exogenous application of carnitine stimulates transportation of fatty acids into mitochondria, which is an important part of fatty acid trafficking in cells, and mitochondrial respiration in the leaves of maize seedlings grown under normal and cold conditions. Cold stress led to significant increases in lipase activity, which is responsible for the breakdown of triacylglycerols, and carnitine acyltransferase (carnitine acyltransferase I and II) activities, which are responsible for the transport of activated long-chain fatty acids into mitochondria. While exogenous application of carnitine has a similar promoting effect with cold stress on lipase activity, it resulted in further increases in the activity of carnitine acyltransferases compared to cold stress. The highest activity levels for these enzymes were recorded in the seedlings treated with cold plus carnitine. In addition, these increases were correlated with positive increases in the contents of free- and long-chain acylcarnitines (decanoyl-l-carnitine, lauroyl-l-carnitine, myristoyl-l-carnitine, and stearoyl-l-carnitine), and with decreases in the total lipid content. The highest values for free- and long-chain acylcarnitines and the lowest value for total lipid content were recorded in the seedlings treated with cold plus carnitine. On the other hand, carnitine with and without cold stress significantly upregulated the expression level of citrate synthase, which is responsible for catalysing the first reaction of the citric acid cycle, and cytochrome oxidase, which is the membrane-bound terminal enzyme in the electron transfer chain, as well as lipase. All these results revealed that on the one hand, carnitine enhanced transport of fatty acids into mitochondria by increasing the activities of lipase and carnitine acyltransferases, and, on the other hand, stimulated mitochondrial respiration in the leaves of maize seedlings grown under normal and cold conditions.
PMID: 31589831
AoB Plants , IF:2.182 , 2019 Dec , V11 (6) : Pplz045 doi: 10.1093/aobpla/plz045
Comparative transcriptome, physiological and biochemical analyses reveal response mechanism mediated by CBF4 and ICE2 in enhancing cold stress tolerance in Gossypium thurberi.
State Key Laboratory of Cotton Biology /Institute of Cotton Research, Chinese Academy of Agricultural Science, Anyang, Henan, China.; College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, China.; School of Biological and Physical Sciences (SBPS), Jaramogi Oginga Odinga University of Science and Technology (JOOUST), Bondo, Kenya.
Low temperature is one of the key environmental stresses that impair plant growth and significantly restricts the productivity and spatial distribution of crop plants. Gossypium thurberi, a wild diploid cotton species, has adapted to a wide range of temperatures and exhibits a better tolerance to chilling stress. Here, we compared phenotypes and physiochemical changes in G. thurberi under cold stress and found this species indeed showed better cold tolerance. Therefore, to understand the molecular mechanisms of the cold tolerance in G. thurberi, we compared transcription changes in leaves of G. thurberi under cold stress by high-throughput transcriptome sequencing. In total, 35 617 unigenes were identified in the whole-genome transcription profile, and 4226 differentially expressed genes (DEGs) were discovered in the leaves upon cold treatment. Gene Ontology (GO) classification analyses showed that the majority of DEGs belonged to categories of signal transduction, transcription factors (TFs) and carbohydrate transport and metabolism. The expression of several cold-responsive genes such as ICE1, CBF4, RAP2-7 and abscisic acid (ABA) biosynthesis genes involved in different signalling pathways were induced after G. thurberi seedlings were exposed to cold stress. Furthermore, cold sensitivity was increased in CBF4 and ICE2 virus-induced gene silencing (VIGS) plants, and high level of malondialdehyde (MDA) showed that the CBF4 and ICE2 silenced plants were under oxidative stress compared to their wild types, which relatively had higher levels of antioxidant enzyme activity, as evident by high levels of proline and superoxide dismutase (SOD) content. In conclusion, our findings reveal a new regulatory network of cold stress response in G. thurberi and broaden our understanding of the cold tolerance mechanism in cotton, which might accelerate functional genomics studies and genetic improvement for cold stress tolerance in cultivated cotton.
PMID: 31777648
Mol Biol Rep , IF:1.402 , 2019 Dec , V46 (6) : P6039-6052 doi: 10.1007/s11033-019-05039-4
Isolation and functional characterization of three abiotic stress-inducible (Apx, Dhn and Hsc70) promoters from pearl millet (Pennisetum glaucum L.).
International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad, 502 324, India.; Department of Genetics, Osmania University, Hyderabad, 500 007, India.; International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad, 502 324, India. p.sudhakarreddy@cgiar.org.
Pearl millet is a C4 cereal crop that grows in arid and semi-arid climatic conditions with the remarkable abiotic stress tolerance. It contributed to the understanding of stress tolerance not only at the physiological level but also at the genetic level. In the present study, we functionally cloned and characterized three abiotic stress-inducible promoters namely cytoplasmic Apx1 (Ascorbate peroxidase), Dhn (Dehydrin), and Hsc70 (Heat shock cognate) from pearl millet. Sequence analysis revealed that all three promoters have several cis-acting elements specific for temporal and spatial expression. PgApx pro, PgDhn pro and PgHsc70 pro were fused with uidA gene in Gateway-based plant transformation pMDC164 vector and transferred into tobacco through leaf-disc method. While PgApx pro and PgDhn pro were active in seedling stages, PgHsc70 pro was active in stem and root tissues of the T2 transgenic tobacco plants under control conditions. Higher activity was observed under high temperature and drought, and less in salt and cold stress conditions. Further, all three promoters displayed higher GUS gene expression in the stem, moderate expression in roots, and less expression in leaves under similar conditions. While RT-qPCR data showed that PgApx pro and PgDhn pro were expressed highly in high temperature, salt and drought, PgHsc70 pro was fairly expressed during high temperature stress only. Histochemical and RT-qPCR assays showed that all three promoters are inducible under abiotic stress conditions. Thus, these promoters appear to be immediate candidates for developing abiotic stress tolerant crops as these promoter-driven transgenics confer high degree of tolerance in comparison with the wild-type (WT) plants.
PMID: 31468258