J Pineal Res , IF:14.528 , 2019 Mar , V66 (2) : Pe12537 doi: 10.1111/jpi.12537
Melatonin-deficient rice plants show a common semidwarf phenotype either dependent or independent of brassinosteroid biosynthesis.
Department of Biotechnology, Bioenergy Research Center, Chonnam National University, Gwangju, South Korea.
Melatonin-deficient rice with a semidwarf erect-leaf phenotype was created by suppressing serotonin N-acetyltransferase 2 (SNAT2). We generated an RNAi transgenic rice that suppressed tryptophan decarboxylase (TDC), which encodes the first TDC enzyme committed step for melatonin biosynthesis in plants catalyzing the conversion of tryptophan into tryptamine, to determine whether other transgenic rice with downregulated melatonin biosynthetic genes exhibited the same erect-leaf phenotype as the snat2 RNAi rice. The TDC RNAi rice produced significantly less melatonin than the wild type and exhibited a semidwarf phenotype, but no erect-leaf phenotype was observed. In contrast, tryptamine 5-hydroxylase (T5H) knockout Sekiguchi rice and caffeic acid O-methyltransferase (COMT) RNAi rice seedlings were semidwarf phenotypes with erect leaves, as was the snat2 RNAi rice due to a melatonin deficiency. All RNAi rice plants showing erect-leaf phenotypes had lower expression levels of the DWARF4 gene, which is a key enzyme for brassinosteroid (BR) biosynthesis, leading to lower BR levels than their respective wild types. Suppressing melatonin synthesis did not alter the contents of indole 3-acetic acid (IAA), suggesting the irrelevance of melatonin deficiency to IAA biosynthesis. These data indicate that a semidwarf seedling is a common rice phenotype by the lack of melatonin synthesis with or without BR suppression in a melatonin biosynthetic gene-specific manner.
PMID: 30403303
Proc Natl Acad Sci U S A , IF:9.412 , 2019 Mar , V116 (12) : P5795-5804 doi: 10.1073/pnas.1815866116
Constitutive signaling activity of a receptor-associated protein links fertilization with embryonic patterning in Arabidopsis thaliana.
Department of Cell Biology, Max Planck Institute for Developmental Biology, 72076 Tuebingen, Germany.; Department of Plant Biology, University of Georgia, Athens, GA 30602.; Developmental Genetics, Centre for Plant Molecular Biology, University of Tuebingen, 72076 Tuebingen, Germany.; Department of Molecular & Cellular Botany, Ruhr-University Bochum, 44780 Bochum, Germany.; Department of Cell Biology, Max Planck Institute for Developmental Biology, 72076 Tuebingen, Germany; martin.bayer@tuebingen.mpg.de.
In flowering plants, the asymmetrical division of the zygote is the first hallmark of apical-basal polarity of the embryo and is controlled by a MAP kinase pathway that includes the MAPKKK YODA (YDA). In Arabidopsis, YDA is activated by the membrane-associated pseudokinase SHORT SUSPENSOR (SSP) through an unusual parent-of-origin effect: SSP transcripts accumulate specifically in sperm cells but are translationally silent. Only after fertilization is SSP protein transiently produced in the zygote, presumably from paternally inherited transcripts. SSP is a recently diverged, Brassicaceae-specific member of the BRASSINOSTEROID SIGNALING KINASE (BSK) family. BSK proteins typically play broadly overlapping roles as receptor-associated signaling partners in various receptor kinase pathways involved in growth and innate immunity. This raises two questions: How did a protein with generic function involved in signal relay acquire the property of a signal-like patterning cue, and how is the early patterning process activated in plants outside the Brassicaceae family, where SSP orthologs are absent? Here, we show that Arabidopsis BSK1 and BSK2, two close paralogs of SSP that are conserved in flowering plants, are involved in several YDA-dependent signaling events, including embryogenesis. However, the contribution of SSP to YDA activation in the early embryo does not overlap with the contributions of BSK1 and BSK2. The loss of an intramolecular regulatory interaction enables SSP to constitutively activate the YDA signaling pathway, and thus initiates apical-basal patterning as soon as SSP protein is translated after fertilization and without the necessity of invoking canonical receptor activation.
PMID: 30833400
Development , IF:5.611 , 2019 Mar , V146 (5) doi: 10.1242/dev.151894
Brassinosteroid signaling in plant development and adaptation to stress.
Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona E-08193, Spain.; Departament de Fisica de la Materia Condensada, Universitat de Barcelona, Barcelona 08028, Spain.; Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, Barcelona 08028, Spain.; Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona E-08193, Spain ana.cano@cragenomica.es.
Brassinosteroids (BRs) are steroid hormones that are essential for plant growth and development. These hormones control the division, elongation and differentiation of various cell types throughout the entire plant life cycle. Our current understanding of the BR signaling pathway has mostly been obtained from studies using Arabidopsis thaliana as a model. In this context, the membrane steroid receptor BRI1 (BRASSINOSTEROID INSENSITIVE 1) binds directly to the BR ligand, triggering a signal cascade in the cytoplasm that leads to the transcription of BR-responsive genes that drive cellular growth. However, recent studies of the primary root have revealed distinct BR signaling pathways in different cell types and have highlighted cell-specific roles for BR signaling in controlling adaptation to stress. In this Review, we summarize our current knowledge of the spatiotemporal control of BR action in plant growth and development, focusing on BR functions in primary root development and growth, in stem cell self-renewal and death, and in plant adaption to environmental stress.
PMID: 30872266
Int J Mol Sci , IF:4.556 , 2019 Mar , V20 (6) doi: 10.3390/ijms20061289
Biosynthesis and Signal Transduction of ABA, JA, and BRs in Response to Drought Stress of Kentucky Bluegrass.
College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China. chenyajun622@163.com.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China. chenyang8368215@hotmail.com.; College of Life Science, Agriculture and Forestry, Qiqihar University, Qiqihar 161006, China. chenyang8368215@hotmail.com.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China. shizj95516@163.com.; College of Life Science, Agriculture and Forestry, Qiqihar University, Qiqihar 161006, China. Jinyifeng8368215@163.com.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China. huashan9303@163.com.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China. xfc204309@163.com.; College of Horticulture and Landscape Architecture, Northeast Agricultural University, Harbin 150030, China. caszhanglu@hotmail.com.
Kentucky bluegrass (KB, Poa pratensis) is one of the most widely used cool-season turfgrass species, but it is sensitive to drought stress. Molecular studies in KB are hindered by its large and complex genome structure. In this study, a comparative transcriptomic study was conducted between a short and long period of water deficiency. Three transcriptome libraries were constructed and then sequenced by using leaf RNA samples of plants at 0, 2, and 16 h after PEG6000 treatment. A total of 199,083 differentially expressed genes (DEGs) were found. The Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation revealed that DEGs were enriched in "Plant hormone signal transduction" and "MAPK signaling pathway-Plant". Some key up-regulated genes, including PYL, JAZ, and BSK, were involved in hormone signaling transduction of abscisic acid, jasmonic acid, and brassinosteroid and possibly these genes play important roles in coping with drought stress in KB. Furthermore, our results showed that the concentrations of ABA, JA and BR increased significantly with the extension of the drought period. The specific DEGs encoding functional proteins, kinase and transcription factors, could be valuable information for genetic manipulation to promote drought tolerance of KB in the future.
PMID: 30875790
Int J Mol Sci , IF:4.556 , 2019 Mar , V20 (5) doi: 10.3390/ijms20051138
Genome-Wide Identification, Expression Profile, and Alternative Splicing Analysis of the Brassinosteroid-Signaling Kinase (BSK) Family Genes in Arabidopsis.
Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China. lizy6@sustc.edu.cn.; Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China. lizy6@sustc.edu.cn.; Co-Innovation Center for Modern Production Technology of Grain Crop, Yangzhou University, Yangzhou 225000, China. shenjinyu20160710@outlook.com.; Department of Biology, Southern University of Science and Technology (SUSTech), Shenzhen 518055, China. liangjs@sustc.edu.cn.
Brassinosteroids (BRs) are steroid hormones essential for different biological processes, ranging from growth to environmental adaptation in plants. The plant brassinosteroid-signaling kinase (BSK) proteins belong to a family of receptor-like cytoplasmic kinases, which have been reported to play an important role in BR signal transduction. However, the knowledge of BSK genes in plants is still quite limited. In the present study, a total of 143 BSK proteins were identified by a genome-wide search in 17 plant species. A phylogenetic analysis showed that the BSK gene originated in embryophytes, with no BSK found in green algae, and these BSK genes were divided into six groups by comparison with orthologs/paralogs. A further study using comparative analyses of gene structure, expression patterns and alternative splicing of BSK genes in Arabidopsis revealed that all BSK proteins shared similar protein structure with some exception and post-translation modifications including sumolyation and ubiquitination. An expression profile analysis showed that most Arabidopsis BSK genes were constitutively expressed in different tissues; of these, several BSK genes were significantly expressed in response to some hormones or abiotic stresses. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) assays showed that BSK5, BSK7, and BSK9 underwent alternative splicing in specific stress induced and tissue-dependent patterns. Collectively, these results lay the foundation for further functional analyses of these genes in plants.
PMID: 30845672
Physiol Plant , IF:4.148 , 2019 Mar , V165 (3) : P555-568 doi: 10.1111/ppl.12750
MaBZR1/2 act as transcriptional repressors of ethylene biosynthetic genes in banana fruit.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables, College of Horticultural Science, South China Agricultural University, Guangzhou, 510642, China.
Banana fruit (Musa acuminate L.) ripening is a complex genetical process affected by multiple phytohormones and expression of various genes. However, whether plant hormone brassinosteroid (BR) is involved in this process remains obscure. In this work, three genes that encode BR core signaling components brassinazole resistant (BZR) proteins, namely MaBZR1 to MaBZR3, were characterized from banana fruit. MaBZR1-MaBZR3 exhibited both nuclear and cytoplasmic localization and behaved as transcription inhibitors. Expression analysis showed that MaBZR1/2/3 were continuously decreased as fruit ripening proceeded, indicating their negative roles in banana ripening. Moreover, gel shift and transient expression assays demonstrated that MaBZR1/2 could suppress the transcription of ethylene biosynthetic genes, including MaACS1, MaACO13 and MaACO14, which increased gradually during the banana ripening, via specifically binding to CGTGT/CG sequence in their promoters. Importantly, exogenous application of BRs promotes banana ripening, which is presumably due to the accelerated expression of MaACS1 and MaACO13/14, and consequently the ethylene production. Our study indicates that MaBZR1/2 act as transcriptional repressors of ethylene biosynthetic genes during banana fruit ripening.
PMID: 29704245
Sci Rep , IF:3.998 , 2019 Mar , V9 (1) : P5002 doi: 10.1038/s41598-019-41428-2
Genome-wide analysis of long non-coding RNAs unveils the regulatory roles in the heat tolerance of Chinese cabbage (Brassica rapa ssp.chinensis).
Wuhan vegetable research institute, Wuhan Academy of Agricultural Science & technology, Wuhan, 430345, China.; Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, 430062, China.; State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, 430072, Wuhan, China.; Wuhan vegetable research institute, Wuhan Academy of Agricultural Science & technology, Wuhan, 430345, China. glzhou@126.com.
Long non-coding RNAs (lncRNAs) mediate important epigenetic regulation in various biological processes related to the stress response in plants. However, the systematic analysis of the lncRNAs expressed in Brassica rapa under heat stress has been elusive. In this study, we performed a genome-wide analysis of the lncRNA expression profiles in non-heading Chinese cabbage leaves using strand-specific RNA-sequencing. A total of 4594 putative lncRNAs were identified with a comprehensive landscape of dynamic lncRNA expression networks under heat stress. Co-expression networks of the interactions among the differentially expressed lncRNAs, mRNAs and microRNAs revealed that several phytohormones were associated with heat tolerance, including salicylic acid (SA) and brassinosteroid (BR) pathways. Of particular importance is the discovery of 25 lncRNAs that were highly co-expressed with 10 heat responsive genes. Thirty-nine lncRNAs were predicted as endogenous target mimics (eTMs) for 35 miRNAs, and five of them were validated to be involved in the heat tolerance of Chinese cabbage. Heat responsive lncRNA (TCONS_00048391) is an eTM for bra-miR164a, that could be a sponge for miRNA binding and may be a competing endogenous RNA (ceRNA) for the target gene NAC1 (Bra030820), affecting the expression of bra-miR164a in Chinese cabbage. Thus, these findings provide new insights into the functions of lncRNAs in heat tolerance and highlight a set of candidate lncRNAs for further studies in non-heading Chinese cabbage.
PMID: 30899041
Plant Genome , IF:3.847 , 2019 Mar , V12 (1) doi: 10.3835/plantgenome2018.04.0022
Transgenerational Response to Heat Stress in the Form of Differential Expression of Noncoding RNA Fragments in Brassica rapa Plants.
Epigenetic regulations in the form of changes in differential expression of noncoding RNAs (ncRNAs) are an essential mechanism of stress response in plants. Previously we showed that heat treatment in L. results in the differential processing and accumulation of ncRNA fragments (ncRFs) stemming from transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), small nuclear RNAs (snRNAs), and small nucleolar RNAs (snoRNAs). In this work, we analyzed whether ncRFs are differentially expressed in the progeny of heat-stressed plants. We found significant changes in the size of tRF reads and a significant decrease in the percentage of tRFs mapping to tRNA-Ala, tRNA-Arg, and tRNA-Tyr and an increase in tRFs mapping to tRNA-Asp. The enrichment analysis showed significant differences in processing of tRFs from tRNA, tRNA, tRNA, tRNA, tRNA, and tRNA isoacceptors. Analysis of potential targets of tRFs showed that they regulate brassinosteroid metabolism, the proton pump ATPase activity, the antiporter activity, the mRNA decay activity as well as nucleosome positioning and the epigenetic regulation of transgenerational response. Gene ontology term analysis of potential targets demonstrated a significant enrichment in tRFs that potentially targeted a cellular component endoplasmic reticulum (ER) and in small nucleolar RNA fragments (snoRFs), the molecular function protein binding. To summarize, our work demonstrated that the progeny of heat-stressed plants exhibit changes in the expression of tRFs and snoRFs but not of small nuclear RNA fragments (snRFs) or ribosomal RNA fragments (rRFs) and these changes likely better prepare the progeny of stressed plants to future stress encounters.
PMID: 30951085
Anal Bioanal Chem , IF:3.637 , 2019 Mar , V411 (8) : P1623-1632 doi: 10.1007/s00216-019-01612-9
A new boronic acid reagent for the simultaneous determination of C27-, C28-, and C29-brassinosteroids in plant tissues by chemical labeling-assisted liquid chromatography-mass spectrometry.
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072, Hubei, China.; Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan, 430072, Hubei, China. yqfeng@whu.edu.cn.
Brassinosteroids (BRs) are endogenous plant growth-promoting hormones affecting growth and development during the entire life cycle of plants. Naturally occurring BRs can be classified into C27-, C28-, or C29-BRs based on the nature of the alkyl groups occupying the C-24 position in the side chain of the 5a-cholestane carbon skeleton. However, while C27-BRs exhibit similar bioactivities to C28- and C29-BRs, the biosynthetic pathways of C27-BRs in plants have not yet been clearly characterized. In addition to a lack of biochemical and enzymatic evidence regarding the biosynthetic pathways of C27-BRs, even most of the intermediate compounds on their pathways have not been explored and identified due to the lower endogenous levels of C27-BRs. Therefore, the development of highly sensitive analytical methods is essential for studying the biosynthetic pathways and physiological functions of C27-BRs. Accordingly, this study establishes qualitative and quantitative methods for identifying and detecting C27-, C28-, and C29-BRs using a newly synthesized boronic acid reagent denoted as 2-methyl-4-phenylaminomethylphenylboronic acid (2-methyl-4-PAMBA) in conjunction with liquid chromatography-mass spectrometry (LC-MS). Labeling with 2-methyl-4-PAMBA provides derivatives with excellent stability, and the detection sensitivities of BRs, particularly for C27-BRs, are dramatically improved. The limits of detection (with a signal-to-noise ratio of 3) for six BRs, including 2 C27-BRs (28-norCS and 28-norBL), 3 C28-BRs (CS, BL, and TY), and a single C29-BR (28-homoBL), are found to be 0.10-1.68 pg/mL after labeling with 2-methyl-4-PAMBA. Finally, the proposed analytical method is successfully applied for the detection of endogenous BRs in small mass samples of Oryza sativa seedlings, Rape flowers, Arabidopsis shoots, and Arabidopsis flowers. In addition, a method for profiling potential BRs in plants is also developed using LC-MS in multiple reaction monitoring scan mode assisted by 2-methyl-4-PAMBA and 2-methyl-4-PAMBA-d5 labeling. The developed method is able to identify 10 potential BRs in a Rape flower extract. The proposed quantitative and qualitative methods established by 2-methyl-4-PAMBA labeling are helpful for facilitating an understanding of the physiological functions and biosynthetic pathways of BRs, particularly for C27-BRs. Graphical abstract.
PMID: 30715574
Plant Sci , IF:3.591 , 2019 Mar , V280 : P31-40 doi: 10.1016/j.plantsci.2018.11.009
Integration of RACK1 and ethylene signaling regulates plant growth and development in Arabidopsis.
Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: 838438746@qq.com.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: wangxutong0019@163.com.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: wangxp439@nenu.edu.cn.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: botanist1@yahoo.com.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: botanistonline@yahoo.com.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: zhangna-0452@qq.com.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China. Electronic address: xym.candy@foxmail.com.; Key Laboratory of Molecular Epigenetics of MOE, Northeast Normal University, Changchun, China; College of Life Science, Linyi University, Linyi, China. Electronic address: wangsc550@nenu.edu.cn.
Arabidopsis RACK1 (Receptors for Activated C Kinase 1) are versatile scaffold proteins that have been shown to be involved in the regulation of plant response to plant hormones including auxin, ABA, gibberellin and brassinosteroid, but not ethylene. By characterizing the double and triple mutants of RACK1 genes, we found that rack1 mutants showed reduced sensitivity to ethylene. By characterizing double and high order mutants generated between ein2, a loss-of-function mutant of the key ethylene signaling regulator gene EIN2 (Ethylene INsensitive 2), and rack1 mutants, we found that loss-of-function of EIN2 partially recovered some phenotypes observed in the rack1 mutants, such as low-fertility and reduced root length and rosette size. On the other hand, the ein2 rack1 mutants produced more rosette leaves, and flowered late when compared with ein2 and the corresponding rack1 mutants. We also found that the curled leaves and twisted petioles phenotypes observed in the ein2 mutants were enhanced in the ein2 rack1 mutants. However, assays in yeast indicated that EIN2 may not physically interact with RACK1. On the other hand, RT-PCR results showed that the expression level of EIN2 was reduced in the rack1 mutants. Taken together, our results suggest that RACKl may integrate ethylene signaling to regulate plant growth and development in Arabidopsis.
PMID: 30824009
BMC Plant Biol , IF:3.497 , 2019 Mar , V19 (1) : P112 doi: 10.1186/s12870-019-1709-y
Mal de Rio Cuarto virus infection causes hormone imbalance and sugar accumulation in wheat leaves.
Instituto de Biotecnologia, CICVyA, INTA, CONICET, Hurlingham, Buenos Aires, Argentina.; Laboratory of Growth Regulators, Palacky University and Institute of Experimental Botany Czech Academy of Sciences, Slechtitelu 27, CZ-78371, Olomouc, Czech Republic.; Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.; Instituto de Patologia Vegetal, CIAP, INTA, Cordoba, Argentina.; Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA.; Instituto de Agrobiotecnologia del Litoral, UNL, CONICET, FBCB, Santa Fe, Argentina.; Instituto de Biotecnologia, CICVyA, INTA, CONICET, Hurlingham, Buenos Aires, Argentina. delvas.mariana@inta.gob.ar.
BACKGROUND: Mal de Rio Cuarto virus (MRCV) infects several monocotyledonous species including maize and wheat. Infected plants show shortened internodes, partial sterility, increased tillering and reduced root length. To better understand the molecular basis of the plant-virus interactions leading to these symptoms, we combined RNA sequencing with metabolite and hormone measurements. RESULTS: More than 3000 differentially accumulated transcripts (DATs) were detected in MRCV-infected wheat plants at 21 days post inoculation compared to mock-inoculated plants. Infected plants exhibited decreased levels of TaSWEET13 transcripts, which are involved in sucrose phloem loading. Soluble sugars, starch, trehalose 6-phosphate (Tre6P), and organic and amino acids were all higher in MRCV-infected plants. In addition, several transcripts related to plant hormone metabolism, transport and signalling were increased upon MRCV infection. Transcripts coding for GA20ox, D14, MAX2 and SMAX1-like proteins involved in gibberellin biosynthesis and strigolactone signalling, were reduced. Transcripts involved in jasmonic acid, ethylene and brassinosteroid biosynthesis, perception and signalling and in auxin transport were also altered. Hormone measurements showed that jasmonic acid, brassinosteroids, abscisic acid and indole-3-acetic acid were significantly higher in infected leaves. CONCLUSIONS: Our results indicate that MRCV causes a profound hormonal imbalance that, together with alterations in sugar partitioning, could account for the symptoms observed in MRCV-infected plants.
PMID: 30902042
Yi Chuan , IF:2.412 , 2019 Mar , V41 (3) : P206-214 doi: 10.16288/j.yczz.18-253
[The BES1/BZR1 transcription factors regulate growth, development and stress resistance in plants].
Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
Brassinosteroid (BR) is a class of plant-specific steroidal hormone and plays vital roles in plant growth, developmental and stress response. As the core component of BR signaling, the BES1/BZR1 transcription factors are activated by the BR signal, bind to the E-box (CANNTG) or BRRE element (CGTGT/CG) enriched in the promoter of downstream target genes and regulate their expression. Besides BR signal transduction, BES1/BZR1s are also involved in other signaling pathways such as abscisic acid, gibberellin and light to co-regulate plant growth and development. Recently, BES1/BZR1s were found to be related to stress resistance. In this review, we summarize recent advances of molecular mechanism of the BES1/BZR1 transcription factors regulating plant growth, development and stress resistance through signal transduction to provide a reference for related researches.
PMID: 30872257
Plant Biol (Stuttg) , IF:2.167 , 2019 Mar , V21 (2) : P326-335 doi: 10.1111/plb.12927
Responses of the weed Bidens pilosa L. to exogenous application of the steroidal saponin protodioscin and plant growth regulators 24-epibrassinolide, indol-3-acetic acid and abscisic acid.
Department of Biochemistry, University of Maringa, Maringa, Brazil.; Department of Sciences of Nature, Federal University of Acre, Rio Branco, Brazil.; Department of Agronomy, University of Londrina, Londrina, Brazil.
The exogenous application of plant hormones and their analogues has been exploited to improve crop performance in the field. Protodioscin is a saponin whose steroidal moiety has some similarities to plant steroidal hormones, brassinosteroids. To test the possibility that protodioscin acts as an agonist or antagonist of brassinosteroids or other plant growth regulators, we compared responses of the weed species Bidens pilosa L. to treatment with protodioscin, brassinosteroids, auxins (IAA) and abscisic acid (ABA). Seeds were germinated and grown in agar containing protodioscin, dioscin, brassinolides, IAA and ABA. Root apex respiratory activity was measured with an oxygen electrode. Malondialdehyde (MDA) and antioxidant enzymes activities were assessed. Protodioscin at 48-240 mum inhibited growth of B. pilosa seedlings. The steroidal hormone 24-epibrassinolide (0.1-5 mum) also inhibited growth of primary roots, but brassicasterol was inactive. IAA at higher concentrations (0.5-10.0 mum) strongly inhibited primary root length and fresh weight of stems. ABA inhibited all parameters of seedling growth and also seed germination. Respiratory activity of primary roots (KCN-sensitive and KCN-insensitive) was activated by protodioscin. IAA and ABA reduced KCN-insensitive respiration. The content of MDA in primary roots increased only after protodioscin treatment. All assayed compounds increased APx and POD activity, with 24-epibrassinolide being most active. The activity of CAT was stimulated by protodioscin and 24-epibrassinolide. The results revealed that protodioscin was toxic to B. pilosa through a mechanism not related to plant growth regulator signalling. Protodioscin caused a disturbance in mitochondrial respiratory activity, which could be related to overproduction of ROS and consequent cell membrane damage.
PMID: 30341820
Dokl Biol Sci , 2019 Mar , V485 (1) : P33-36 doi: 10.1134/S0012496619020017
The Endogenous Brassinosteroid Content and Balance in Potato Microclones Is Determined by Organ Specificity and the Variety Ripening Term.
National Research Tomsk State University, 634050, Tomsk, Russia. stevmv555@gmail.com.; Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, 220141, Minsk, Belarus.; National Research Tomsk State University, 634050, Tomsk, Russia.; Timiryazev Institute of Plant Physiology, Russian Academy of Science, 127276, Moscow, Russia.
The brassinosteroid (BS) profiles in shoots and roots of the potato plants were shown to be organ-specific and dependent on the term of variety ripening. The amount of all studied groups of steroid phytohormones proved to be an order of magnitude higher in roots than in shoots. In roots, the brassinosteroid lactones predominated, while in shoots, their biogenetic precursors, 6-ketones, were prevailing. The early-ripening variety Zhukovsky Early is characterized by a high content of almost all BS groups (first of all, brassinolide group) and a relatively high content of B-lactones in shoots. With aging, the content of B-lactones in plants decreases, while that of B-ketones grows up.
PMID: 31197590