Mol Plant , IF:13.164 , 2021 Jul , V14 (7) : P1185-1198 doi: 10.1016/j.molp.2021.05.005
The miR166-SlHB15A regulatory module controls ovule development and parthenocarpic fruit set under adverse temperatures in tomato.
Institute of Plant Sciences Paris-Saclay, INRAE, CNRS, Universite Paris-Saclay, Orsay 91405, France.; Institut Jean-Pierre Bourgin, INRAE, Versailles, France.; HM Clause, Mas Saint-Pierre, Quartier La Galine, Saint-Remy de Provence 13210, France.; Hazera Seeds Ltd, Berurim M.P., Shikmim 7983700, Israel.; Institute of Plant Sciences Paris-Saclay, INRAE, CNRS, Universite Paris-Saclay, Orsay 91405, France. Electronic address: abdelhafid.bendahmane@inrae.fr.
Fruit set is inhibited by adverse temperatures, with consequences on yield. We isolated a tomato mutant producing fruits under non-permissive hot temperatures and identified the causal gene as SlHB15A, belonging to class III homeodomain leucine-zipper transcription factors. SlHB15A loss-of-function mutants display aberrant ovule development that mimics transcriptional changes occurring in fertilized ovules and leads to parthenocarpic fruit set under optimal and non-permissive temperatures, in field and greenhouse conditions. Under cold growing conditions, SlHB15A is subjected to conditional haploinsufficiency and recessive dosage sensitivity controlled by microRNA 166 (miR166). Knockdown of SlHB15A alleles by miR166 leads to a continuum of aberrant ovules correlating with parthenocarpic fruit set. Consistent with this, plants harboring an Slhb15a-miRNA166-resistant allele developed normal ovules and were unable to set parthenocarpic fruit under cold conditions. DNA affinity purification sequencing and RNA-sequencing analyses revealed that SlHB15A is a bifunctional transcription factor expressed in the ovule integument. SlHB15A binds to the promoters of auxin-related genes to repress auxin signaling and to the promoters of ethylene-related genes to activate their expression. A survey of tomato genetic biodiversity identified pat and pat-1, two historical parthenocarpic mutants, as alleles of SlHB15A. Taken together, our findings demonstrate the role of SlHB15A as a sentinel to prevent fruit set in the absence of fertilization and provide a mean to enhance fruiting under extreme temperatures.
PMID: 33964458
Ecol Lett , IF:9.492 , 2021 Jul doi: 10.1111/ele.13827
Global trends in phenotypic plasticity of plants.
Sustainability Research Centre, Life Sciences Faculty, Universidad Andres Bello, Santiago, Chile.; Departamento de Biologia, Universidad de La Serena, La Serena, Chile.; Laboratorio de Biologia Vegetal, Instituto de Ciencias Biologicas, Universidad de Talca, Talca, Chile.; Departamento de Biogeografia y Cambio Global, LINCGlobal, Museo Nacional de Ciencias Naturales, MNCN-CSIC, Madrid, Espana.; Area de Biodiversidad y Conservacion, Universidad Rey Juan Carlos, Mostoles, Madrid, Espana.; Departamento de Botanica, Universidad de Concepcion, Concepcion, Chile.
Predicting plastic responses is crucial to assess plant species potential to adapt to climate change, but little is known about which factors drive the biogeographical patterns of phenotypic plasticity in plants. Theory predicts that climatic variability would select for increased phenotypic plasticity, whereas evidence indicates that stressful conditions can limit phenotypic plasticity. Using a meta-analytic, phylogeny-corrected approach to global data on plant phenotypic plasticity, we tested whether latitude, climate, climatic variability and/or stressful conditions are predictors of plastic responses at a biogeographical scale. We found support for a positive association between phenotypic plasticity and climatic variability only for plasticity in allocation. Plasticity in leaf morphology, size and physiology were positively associated with mean annual temperature. We also found evidence that phenotypic plasticity in physiology is limited by cold stress. Overall, plant plastic responses to non-climatic factors were stronger than responses to climatic factors. However, while climatic conditions were associated with plant plastic responses to climatic factors, they generally did not relate to plastic responses to other abiotic or biotic factors. Our study highlights the need to consider those factors that favour and limit phenotypic plasticity in order to improve predictive frameworks addressing plant species' potential to adapt to climate change.
PMID: 34216183
Cell Rep , IF:9.423 , 2021 Jul , V36 (3) : P109397 doi: 10.1016/j.celrep.2021.109397
Integrated global analysis reveals a vitamin E-vitamin K1 sub-network, downstream of COLD1, underlying rice chilling tolerance divergence.
Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China.; State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; University of Chinese Academy of Sciences, Beijing 100049, China. Electronic address: chongk@ibcas.ac.cn.; Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China. Electronic address: jingyuzhang@ibcas.ac.cn.
Rice, a staple food with tropical/subtropical origination, is susceptible to cold stress, one of the major constraints on its yield and distribution. Asian cultivated rice consists of two subspecies with diverged chilling tolerance to adapt to different environments. The mechanism underlying this divergence remains obscure with a few known factors, including membrane protein CHILLING-TOLERANCE DIVERGENCE 1 (COLD1). Here, we reveal a vitamin E-vitamin K1 sub-network responsible for chilling tolerance divergence through global analyses. Rice genome regions responsible for tolerance divergence are identified with chromosome segment substitution lines (CSSLs). Comparative transcriptomic and metabolomic analysis of chilling-tolerant CSSL4-1 and parent lines uncovered a vitamin E-vitamin K1 sub-network in chloroplast with tocopherol (vitamin E) mediating chloroplast-to-nucleus signaling. COLD1, located in the substitution segment in CSSL4-1, is confirmed as its upstream regulator by transgenic material analysis. Our work uncovers a pathway downstream of COLD1, through which rice modulates chilling tolerance for thermal adaptation, with potential utility in crop improvement.
PMID: 34289369
J Exp Bot , IF:6.992 , 2021 Jul doi: 10.1093/jxb/erab334
Cold response and tolerance in cereal roots.
INRES, Institute of Crop Science and Resource Conservation, Crop Functional Genomics, University of Bonn, 53113 Bonn, Germany.
Cold stress adversely affects plant growth and is a limiting factor in crop productivity. Temperature volatility as a consequence of climate change will increase the effects of cold stress on crop cultivation. Low temperatures frequently occur early after planting in temperate climates and severely affect root development in cereals. In this review we address the question how cereal root systems respond to cold on different scales. First, we summarize the morphological, physiological and cellular responses of cereal roots to cold stress and how these processes are regulated by phytohormones. Subsequently, we highlight the status of the genetic and molecular dissection of cold tolerance with emphasis on the role of cold-responsive genes in improving cold tolerance in cereal roots. Finally, we discuss the role of beneficial microorganisms and mineral nutrients in ameliorating the effects of cold stress in cereal roots. A comprehensive knowledge of the molecular mechanisms underlying cold tolerance will ensure yield stability by enabling the generation of cold-tolerant crop genotypes.
PMID: 34270744
J Exp Bot , IF:6.992 , 2021 Jul doi: 10.1093/jxb/erab323
Tissue-level transcriptomic responses to local and distal chilling reveal potential chilling survival mechanisms in maize.
College of Plant Science, Jilin University, Changchun 130062, P.R. China.; Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.
Chilling is a major stress to plants of subtropical and tropical origins including maize (Zea mays L.). To reveal molecular mechanisms underlying chilling tolerance and survival, we investigated transcriptomic responses to chilling stress in differentiated leaves and roots as well as in crowns with meristem activity in maize. Chilling stress on shoots and roots is found to each contributes to seedling lethality in maize. Comparison of maize lines with different chilling tolerance capacities reveals that chilling survival is highly associated with upregulation of abscisic acid biosynthesis and response as well as transcriptional regulators in leaves and crowns. It is also associated with the downregulation of translation in leaves and heat response in crowns. Chilling treatment on whole or part of the plants reveals that response to distal-chilling is very distinct from, and sometimes opposite to, response to local- or whole-plant chilling in both leaves and roots, suggesting a communication between shoots and roots in environmental response. This study thus provides transcriptomic responses in leaves, roots and crowns under differential chilling stresses in maize and reveals potential chilling tolerance and survival mechanisms which lays ground for improving chilling tolerance in crop plants.
PMID: 34240135
Int J Mol Sci , IF:5.923 , 2021 Jul , V22 (14) doi: 10.3390/ijms22147269
Genome-Wide Identification, Structure Characterization, and Expression Pattern Profiling of the Aquaporin Gene Family in Betula pendula.
Universite Clermont Auvergne, INRAE, PIAF, 63000 Clermont-Ferrand, France.; Institute of Ecology and Earth Sciences, University of Tartu, 51005 Tartu, Estonia.; National Institute of Agronomy of Tunisia (INAT), Crop Improvement Laboratory, INRAT, Tunis CP 1004, Tunisia.; Laboratory of Plant Biotechnology, Ecology and Ecosystem Valorization, Faculty of Sciences, University Chouaib Doukkali, El Jadida 24000, Morocco.; State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, Harbin 150040, China.
Aquaporin water channels (AQPs) constitute a large family of transmembrane proteins present throughout all kingdoms of life. They play key roles in the flux of water and many solutes across the membranes. The AQP diversity, protein features, and biological functions of silver birch are still unknown. A genome analysis of Betula pendula identified 33 putative genes encoding full-length AQP sequences (BpeAQPs). They are grouped into five subfamilies, representing ten plasma membrane intrinsic proteins (PIPs), eight tonoplast intrinsic proteins (TIPs), eight NOD26-like intrinsic proteins (NIPs), four X intrinsic proteins (XIPs), and three small basic intrinsic proteins (SIPs). The BpeAQP gene structure is conserved within each subfamily, with exon numbers ranging from one to five. The predictions of the aromatic/arginine selectivity filter (ar/R), Froger's positions, specificity-determining positions, and 2D and 3D biochemical properties indicate noticeable transport specificities to various non-aqueous substrates between members and/or subfamilies. Nevertheless, overall, the BpePIPs display mostly hydrophilic ar/R selective filter and lining-pore residues, whereas the BpeTIP, BpeNIP, BpeSIP, and BpeXIP subfamilies mostly contain hydrophobic permeation signatures. Transcriptional expression analyses indicate that 23 BpeAQP genes are transcribed, including five organ-related expressions. Surprisingly, no significant transcriptional expression is monitored in leaves in response to cold stress (6 degrees C), although interesting trends can be distinguished and will be discussed, notably in relation to the plasticity of this pioneer species, B. pendula. The current study presents the first detailed genome-wide analysis of the AQP gene family in a Betulaceae species, and our results lay a foundation for a better understanding of the specific functions of the BpeAQP genes in the responses of the silver birch trees to cold stress.
PMID: 34298887
Int J Mol Sci , IF:5.923 , 2021 Jul , V22 (13) doi: 10.3390/ijms22137203
Effect of Short-Term Cold Treatment on Carbohydrate Metabolism in Potato Leaves.
Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences-SGGW, 02-776 Warsaw, Poland.; Biopolymer Analytics, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Str. 24-25 Building 20, 14476 Potsdam-Golm, Germany.
Plants are often challenged by an array of unfavorable environmental conditions. During cold exposure, many changes occur that include, for example, the stabilization of cell membranes, alterations in gene expression and enzyme activities, as well as the accumulation of metabolites. In the presented study, the carbohydrate metabolism was analyzed in the very early response of plants to a low temperature (2 degrees C) in the leaves of 5-week-old potato plants of the Russet Burbank cultivar during the first 12 h of cold treatment (2 h dark and 10 h light). First, some plant stress indicators were examined and it was shown that short-term cold exposure did not significantly affect the relative water content and chlorophyll content (only after 12 h), but caused an increase in malondialdehyde concentration and a decrease in the expression of NDA1, a homolog of the NADH dehydrogenase gene. In addition, it was shown that the content of transitory starch increased transiently in the very early phase of the plant response (3-6 h) to cold treatment, and then its decrease was observed after 12 h. In contrast, soluble sugars such as glucose and fructose were significantly increased only at the end of the light period, where a decrease in sucrose content was observed. The availability of the monosaccharides at constitutively high levels, regardless of the temperature, may delay the response to cold, involving amylolytic starch degradation in chloroplasts. The decrease in starch content, observed in leaves after 12 h of cold exposure, was preceded by a dramatic increase in the transcript levels of the key enzymes of starch degradation initiation, the alpha-glucan, water dikinase (GWD-EC 2.7.9.4) and the phosphoglucan, water dikinase (PWD-EC 2.7.9.5). The gene expression of both dikinases peaked at 9 h of cold exposure, as analyzed by real-time PCR. Moreover, enhanced activities of the acid invertase as well as of both glucan phosphorylases during exposure to a chilling temperature were observed. However, it was also noticed that during the light phase, there was a general increase in glucan phosphorylase activities for both control and cold-stressed plants irrespective of the temperature. In conclusion, a short-term cold treatment alters the carbohydrate metabolism in the leaves of potato, which leads to an increase in the content of soluble sugars.
PMID: 34281256
Front Plant Sci , IF:5.753 , 2021 , V12 : P676884 doi: 10.3389/fpls.2021.676884
Cold Stress in Wheat: Plant Acclimation Responses and Management Strategies.
School of Agronomy, Anhui Agricultural University, Hefei, China.; Department of Plant Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman.; Agronomy (Forage Production) Section, Ayub Agricultural Research Institute, Faisalabad, Pakistan.; Jiangsu Collaborative Innovation Centre for Modern Crop Production, Nanjing, China.
Unpredicted variability in temperature is associated with frequent extreme low-temperature events. Wheat is a leading crop in fulfilling global food requirements. Climate-driven temperature extremes influence the vegetative and reproductive growth of wheat, followed by a decrease in yield. This review describes how low temperature induces a series of modifications in the morphophysiological, biochemical, and molecular makeup of wheat and how it is perceived. To cope with these modifications, crop plants turn on their cold-tolerance mechanisms, characterized by accumulating soluble carbohydrates, signaling molecules, and cold tolerance gene expressions. The review also discusses the integrated management approaches to enhance the performance of wheat plants against cold stress. In this review, we propose strategies for improving the adaptive capacity of wheat besides alleviating risks of cold anticipated with climate change.
PMID: 34305976
Front Plant Sci , IF:5.753 , 2021 , V12 : P698525 doi: 10.3389/fpls.2021.698525
Genome-Wide Characterization of B-Box Gene Family and Its Roles in Responses to Light Quality and Cold Stress in Tomato.
College of Horticulture, Shenyang Agricultural University, Shenyang, China.; Key Laboratory of Protected Horticulture, Ministry of Education, Shenyang, China.; National & Local Joint Engineering Research Center of Northern Horticultural Facilities Design & Application Technology, Shenyang, China.; College of Land and Environment, Shenyang Agricultural University, Shenyang, China.; College of Agronomy, Jiangxi Agricultural University, Nanchang, China.; College of Forestry, Henan University of Science and Technology, Luoyang, China.
Perceiving incoming environmental information is critical for optimizing plant growth and development. Multiple B-box proteins (BBXs) play essential roles in light-dependent developmental processes in plants. However, whether BBXs function as a signal integrator between light and temperature in tomato plants remains elusive. In this study, 31 SlBBX genes were identified from the newly released tomato (Solanum lycopersicum) genome sequences and were clustered into five subgroups. Gene structure and protein motif analyses showed relatively high conservation of closely clustered SlBBX genes within each subgroup; however, genome mapping analysis indicated the uneven distribution of the SlBBX genes on tomato chromosomes. Promoter cis-regulatory elements prediction and gene expression indicated that SlBBX genes were highly responsive to light, hormones, and stress conditions. Reverse genetic approaches revealed that disruption of SlBBX7, SlBBX9, and SlBBX20 largely suppressed the cold tolerance of tomato plants. Furthermore, the impairment of SlBBX7, SlBBX9, and SlBBX20 suppressed the photosynthetic response immediately after cold stress. Due to the impairment of non-photochemical quenching (NPQ), the excess photon energy and electron flow excited by low temperature were not consumed in SlBBX7-, SlBBX9-, and SlBBX20- silenced plants, leading to the over reduction of electron carriers and damage of the photosystem. Our study emphasized the positive roles of light signaling transcription factors SlBBXs in cold tolerance in tomato plants, which may improve the current understanding of how plants integrate light and temperature signals to adapt to adverse environments.
PMID: 34290726
Plant Cell Physiol , IF:4.927 , 2021 Jul doi: 10.1093/pcp/pcab115
Characterization of Chromatin Accessibility and Gene Expression Upon Cold Stress Reveals the Transcription Factor RAV1 Functions in Cold Response in Vitis amurensis.
Beijing Key Laboratory of Grape Sciences and Enology, Key Laboratory of Plant Resource, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, PR China.; University of Chinese Academy of Sciences, Beijing 100049, PR China.; EGFV, Bordeaux Sciences Agro, INRA, Universite de Bordeaux, ISVV, 33140 Villenave d'Ornon, France.; Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, PR China.
Cold tolerance is regulated by a variety of transcription factors (TFs) and their target genes. Except for the well-characterized C-repeat binding factors (CBFs)-dependent transcriptional cascade, the mechanisms of cold tolerance mediated by other transcriptional regulatory networks are still largely unknown. Here we used the assay for transposase-accessible chromatin with sequencing (ATAC-seq) and RNA-seq to identify cold responsive TFs in Vitis amurensis, a grape species with high cold hardiness. A number of 9 TFs, including CBF4, RAV1 and ERF104, were identified after cold treatment. Weighted gene co-expression network analysis (WGCNA) and gene ontology (GO) analysis revealed that these TFs may regulate cold response through different pathways. As a prime candidate TF, overexpression of VaRAV1 in grape cells improved its cold tolerance. The transgenic cells exhibited low electrolyte leakage and malondialdehyde (MDA) content and high peroxidase (POD) activity. Moreover, the TF gene TCP8 and a gene involving in homogalacturonan biosynthesis were found to be regulated by VaRAV1, suggesting that the contribution of VaRAV1 to cold tolerance may be achieved by enhancing stability of cell membrane and regulating the expression of target genes involved in plant cell wall composition. Our work provides novel insights into plant response to cold stress and demonstrates the utility of ATAC-seq and RNA-seq for rapid identification of TFs in response to cold stress in grapevine. The VaRAV1 may play an important role in adaption to cold stress.
PMID: 34279666
Plant Cell Physiol , IF:4.927 , 2021 Jul doi: 10.1093/pcp/pcab103
Responses of the Plant Cell Wall to Sub-Zero Temperatures: A Brief Update.
Graduate School of Science & Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama 338-8570, Japan.; Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA.; Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA.; Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI 48824, USA.; Obihiro University of Agricultural and Veterinary Medicine, Nishi 2-11, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.; USDA and Department of Crop Science, North Carolina State University, Raleigh, NC 27695, USA.
Our general understanding of plant responses to sub-zero temperatures focuses on mechanisms that mitigate stress to the plasma membrane. The plant cell wall receives comparatively less attention and questions surrounding its role in mitigating freezing injury remains unresolved. Despite recent molecular discoveries that provide insight into acclimation responses, the goal of reducing freezing injury in herbaceous and woody crops remains elusive. This is likely due to the complexity associated with adaptations to low temperatures. Understanding how leaf cell walls of herbaceous annuals promote tissue tolerance to ice does not necessarily lead to understanding how meristematic tissues are protected from freezing by tissue-level barriers formed by cell walls in overwintering tree buds. In this mini-review, we provide an overview of biological ice nucleation and explain how plants control the spatiotemporal location of ice formation. We discuss how sugars and pectin side chains alleviate adhesive injury that develops at sub-zero temperatures between the matrix polysaccharides and ice. The importance of site-specific cell wall elasticity to promote tissue expansion for ice accommodation and control of porosity to impede ice growth and promote supercooling will be presented. How specific cold-induced proteins modify plant cell walls to mitigate freezing injury will also be discussed. The opinions presented in this report emphasize the importance of a plant's developmental physiology when characterizing mechanisms of freezing survival.
PMID: 34240199
Plant Cell Physiol , IF:4.927 , 2021 Jul , V62 (3) : P502-514 doi: 10.1093/pcp/pcab013
Natural Variation among Arabidopsis Accessions in the Regulation of Flavonoid Metabolism and Stress Gene Expression by Combined UV Radiation and Cold.
Max-Planck-Institut fr Molekulare Pflanzenphysiologie, Am Mhlenberg 1, Potsdam 14476, Germany.; MetaSysX GmbH, Am Mhlenberg 11, Potsdam 14476, Germany.; Graduate School of Biological Science, Nara Institute of Science and Technology (NAIST), Ikoma, 630-0192 Japan.; Research Unit Environmental Simulation, Institute of Biochemical Plant Pathology, Helmholtz Zentrum Mnchen, German Research Center for Environmental Health, Ingolstdter Landstr. 1, Neuherberg 85764, Germany.; Deutsches Patent- und Markenamt, Zweibrckenstr. 12, Mnchen 80331, Germany.; Institute of Biochemical Plant Pathology, Helmholtz Zentrum Mnchen, German Research Center for Environmental Health, Ingolstdter Landstr. 1, Neuherberg 85764, Germany.
Plants are constantly exposed to stressful environmental conditions. Plant stress reactions were mainly investigated for single stress factors. However, under natural conditions plants may be simultaneously exposed to different stresses. Responses to combined stresses cannot be predicted from the reactions to the single stresses. Flavonoids accumulate in Arabidopsis thaliana during exposure to UV-A, UV-B or cold, but the interactions of these factors on flavonoid biosynthesis were unknown. We therefore investigated the interaction of UV radiation and cold in regulating the expression of well-characterized stress-regulated genes, and on transcripts and metabolites of the flavonoid biosynthetic pathway in 52 natural Arabidopsis accessions that differ widely in their freezing tolerance. The data revealed interactions of cold and UV on the regulation of stress-related and flavonoid biosynthesis genes, and on flavonoid composition. In many cases, plant reactions to a combination of cold and UV were unique under combined stress and not predictable from the responses to the single stresses. Strikingly, all correlations between expression levels of flavonoid biosynthesis genes and flavonol levels were abolished by UV-B exposure. Similarly, correlations between transcript levels of flavonoid biosynthesis genes or flavonoid contents, and freezing tolerance were lost in the presence of UV radiation, while correlations with the expression levels of cold-regulated genes largely persisted. This may indicate different molecular cold acclimation responses in the presence or absence of UV radiation.
PMID: 33544865
Physiol Plant , IF:4.5 , 2021 Jul doi: 10.1111/ppl.13506
Assessing growth, frost tolerance and acclimation of pine seedlings with contrasted dormancy strategies as influenced by organic nitrogen supply.
Departamento de Sistemas y Recursos Naturales, ETS Ingenieros de Montes, Forestal y del Medio Natural, Universidad Politecnica de Madrid, Madrid, Spain.; Forest Plantations and Agroforestry Program. Campo Experimental Valle del Guadiana. Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias (INIFAP), Durango, Mexico.; Forest Ecology and Restoration Group. Departamento de Ciencias de la Vida. Universidad de Alcala. Apdo, Madrid, Spain.
Freezing stress is a critical environmental factor affecting survival, distribution, and evolution of plants. Although there is evidence that nitrogen (N) affects frost tolerance of juvenile conifers, the magnitude and direction of such effect can diverge among species. The influence of the N source on frost tolerance has been barely studied. Particularly, how organic N sources could affect the cold acclimation dynamics of seedlings is poorly understood. We studied morpho-physiological responses to organic N supply (amino acids) in comparison to inorganic N in seedlings of two Mediterranean pine species: Pinus halepensis and P. sylvestris. Fertilization was applied at low and high N doses (30 and 130 mg N seedling(-1) ) in the first growing season. Then, tolerance of seedlings to freezing stress was evaluated through the cold season. This study confirmed that organic N supply promotes growth of both species as effectively as inorganic N sources. At low N availability, seedlings had acute P deficiencies when grown with inorganic N, but not with organic N. Likewise, high organic-N availability improved chlorophylls concentration. Both species increased their frost tolerance through time, especially during late autumn. Although organic N supply did not show clear benefits on frost tolerance, it seemed to enhance cold acclimation via increases of compatible solutes, such as soluble sugars and proline, particularly in P. halepensis. Thus, the effects of organic N supply could depend on the extent that such osmolytes contribute to the dormancy strategy of the species. Other species-specific mechanisms to cope with freezing stress are further discussed. This article is protected by copyright. All rights reserved.
PMID: 34287917
Sci Rep , IF:4.379 , 2021 Jul , V11 (1) : P14429 doi: 10.1038/s41598-021-93383-6
Expression profiling of the Dof gene family under abiotic stresses in spinach.
College of Agriculture, Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.; Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.; Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA. rayming@illinois.edu.
DNA-binding with one finger (Dof) are plant-specific transcription factors involved in numerous pathways of plant development, such as abiotic stresses responses. Although genome-wide analysis of Dof genes has been performed in many species, but these genes in spinach have not been analyzed yet. We performed a genome-wide analysis and characterization of Dof gene family in spinach (Spinacia oleracea L.). Twenty-two Dof genes were identified and classified into four groups with nine subgroups, which was further corroborated by gene structure and motif analyses. Ka/Ks analysis revealed that SoDofs were subjected to purifying selection. Using cis-acting elements analysis, SoDofs were involved in plant growth and development, plant hormones, and stress responses. Expression profiling demonstrated that SoDofs expressed in leaf and inflorescence, and responded to cold, heat, and drought stresses. SoDof22 expressed the highest level in male flowers and under cold stress. These results provided a genome-wide analysis of SoDof genes, their gender- and tissue-specific expression, and response to abiotic stresses. The knowledge and resources gained from these analyses will benefit spinach improvement.
PMID: 34257328
Ann Bot , IF:4.357 , 2021 Jul doi: 10.1093/aob/mcab091
Revision of the relationship between anther morphology and pollen sterility by cold stress at the booting stage in rice.
Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.; National Agriculture and Food Research Organization Hokkaido Agricultural Research Center, Sapporo, Japan.
BACKGROUND AND AIMS: Cold stress in rice (Oryza sativa) plants at the reproductive stage prevents normal anther development and causes pollen sterility. Tapetum hypertrophy in anthers has been associated with pollen sterility in response to cold at the booting stage. Here, we reexamined whether the relationships between anther abnormality and pollen sterility caused by cold stress at the booting stage in rice can be explained by a monovalent factor such as tapetum hypertrophy. METHODS: After exposing plants to a 4-day cold treatment at the booting stage, we collected and processed anthers for transverse sectioning immediately and at the flowering stage. We anatomically evaluated the effect of cold treatment on anther internal morphologies, pollen fertilities and pollen numbers in the 13 cultivars with various cold sensitivities. KEY RESULTS: We observed four types of morphological anther abnormalities at each stage. Pollen sterility was positively correlated with the frequency of undeveloped locules, but not with tapetum hypertrophy as commonly believed. In cold-sensitive cultivars grown at low temperatures, pollen sterility was more frequent than anther morphological abnormalities, and some lines showed remarkably high pollen sterility without any anther morphological alterations. Most morphological anomalies occurred only in specific areas within large and small locules. Anther length tended to shorten in response to cold treatment and was positively correlated with pollen number. One cultivar showed a considerably reduced pollen number, but fertile pollen grains under cold stress. We propose three possible relationships to explain anther structure and pollen sterility and reduction due to cold stress. CONCLUSIONS: The pollen sterility caused by cold stress at the booting stage was correlated with the frequency of entire locule-related abnormalities, which might represent a phenotypic consequence, but not a direct cause of pollen abortion. Multivalent factors might underly the complicated relationships between anther abnormality and pollen sterility in rice.
PMID: 34232290
Plant Physiol Biochem , IF:4.27 , 2021 Jul , V166 : P1054-1064 doi: 10.1016/j.plaphy.2021.07.011
Abscisic acid and putrescine synergistically regulate the cold tolerance of melon seedlings.
Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, College of Horticulture, Shenyang Agricultural University, National and Local Joint Engineering Research Centre of Northern Horticultural, Facilities Design and Application Technology (Liaoning), Shenyang, 110866, Liaoning, PR China.; Department of Life Science, Dezhou University, Dezhou, 253023, Shandong, PR China.; Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, College of Horticulture, Shenyang Agricultural University, National and Local Joint Engineering Research Centre of Northern Horticultural, Facilities Design and Application Technology (Liaoning), Shenyang, 110866, Liaoning, PR China. Electronic address: taoliu@syau.edu.cn.; Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, College of Horticulture, Shenyang Agricultural University, National and Local Joint Engineering Research Centre of Northern Horticultural, Facilities Design and Application Technology (Liaoning), Shenyang, 110866, Liaoning, PR China. Electronic address: qihongyan@syau.edu.cn.
Low temperature in early spring severely endangers the growth and development of melon seedlings. Abscisic acid (ABA) and polyamines (PAs) are important signal molecules in plant response to stress. However, the issue of whether they interact to regulate melon cold tolerance remains largely uncharacterized. Here, we identified a total of 14 key genes related to ABA and PAs biosynthesis, including four CmNCEDs, and ten genes in PA pathway (one CmADC, one CmODC, four CmSAMDCs, two CmSPDSs, and two CmSPAMs). Two oriental melon cultivars (IVF571, cold-tolerant; IVF004, cold-sensitive) were selected to explore the difference of ABA and PAs biosynthesis under cold stress (15 degrees C/6 degrees C, day/night). Results showed that the expressions of CmNCED3, CmNCED3-2, CmADC, CmSAMDCs, CmSPDS2 and CmSPMS1 were significantly up-regulated. ABA and putrescine levels were significantly increased in IVF571 under cold stress. Inhibiting the biosynthesis of endogenous ABA with nordihydroguaiaretic acid (NDGA) or Put with D-Arginine (D-Arg) dramatically decreased the levels of each other and aggravated the cold injury of melon seedlings. In addition, spraying with exogenous 75 muM ABA or 1 mM Put improved the activities of superoxide dismutase, catalase and ascorbate peroxidase, and reduced the membrane lipid peroxidation damage of melon seedlings under cold stress. In all, the higher cold tolerance of IVF571 seedlings than that of IVF004 seedlings might be related to the increase in ABA and Put levels triggered by cold stress. ABA and Put could regulate the biosynthesis of each other and might act as signals to trigger the antioxidant system, thereby increasing melon cold tolerance.
PMID: 34293605
Plant Mol Biol , IF:4.076 , 2021 Jul doi: 10.1007/s11103-021-01169-1
The lincRNA XH123 is involved in cotton cold-stress regulation.
Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China.; College of Agriculture, Engineering Research Center of Ministry of Cotton Education, Xinjiang Agricultural University, 311 Nongda East Road, Urumqi, 830052, China.; Hainan Institute of Zhejiang University, Building 11, Yonyou Industrial Park, Yazhou Bay Science and Technology City, Yazhou District, Sanya, 572025, Hainan, China.; Zhejiang Provincial Key Laboratory of Crop Genetic Resources, Institute of Crop Science, Plant Precision Breeding Academy, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, China. xueyingguan@zju.edu.cn.
KEY MESSAGE: We characterize a functional lincRNA, XH123 in cotton seedling in defense of cold stress. The silencing of XH123 leads to increased sensitivity to cold stress and the decay of chloroplast. Cotton, which originated from the arid mid-American region, is one of the most important cash crops worldwide. Cultivated cotton is now widely spread throughout high-altitude regions such as those in the far northwest of Asia. In such areas, spring temperatures below 12 impose cold stress on cotton seedlings, with concomitant threat of lost yield and productivity. It is documented that cold stress can induce differential expression of long noncoding RNAs (lncRNAs) in cotton; however, it is not yet clear if these cold-responsive lncRNAs are actively involved with tolerance of cold stress at the molecular level. Here, we select ten long intergenic non-coding RNAs as candidate genes and use virus-induced gene silencing and additional cold treatments to examine their roles in the response to cold stress during the cotton seedling stage. One such gene, XH123, was revealed to be involved in tolerance of cold stress. Specifically, XH123-silenced plants demonstrated sensitivity to cold stress, exhibiting chloroplast damage and increased endogenous levels of reactive oxygen species. The transcriptome profile of XH123-silenced seedlings was similar to that of cold-stressed seedlings having the known cold stress gene PIF3 silenced. These results imply that the lincRNA XH123 is actively involved with cold stress regulation in cotton during the seedling stage.
PMID: 34224063
Protoplasma , IF:3.356 , 2021 Jul doi: 10.1007/s00709-021-01682-6
Winter survival of the unicellular green alga Micrasterias denticulata: insights from field monitoring and simulation experiments.
Department of Biosciences, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria.; Institute of Pharmacology, University of Linz, Huemerstrasse 3-5, 4020, Linz, Austria.; Department of Biosciences, University of Salzburg, Hellbrunnerstrasse 34, 5020, Salzburg, Austria. mail@o.buchner.co.uk.; Department of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria.
Peat bog pools around Tamsweg (Lungau, Austria) are typical habitats of the unicellular green alga Micrasterias denticulata. By measurement of water temperature and irradiation throughout a 1-year period (2018/2019), it was intended to assess the natural environmental strain in winter. Freezing resistance of Micrasterias cells and their ability to frost harden and become tolerant to ice encasement were determined after natural hardening and exposure to a cold acclimation treatment that simulated the natural temperature decrease in autumn. Transmission electron microscopy (TEM) was performed in laboratory-cultivated cells, after artificial cold acclimation treatment and in cells collected from field. Throughout winter, the peat bog pools inhabited by Micrasterias remained unfrozen. Despite air temperature minima down to -17.3 degrees C, the water temperature was mostly close to +0.8 degrees C. The alga was unable to frost harden, and upon ice encasement, the cells showed successive frost damage. Despite an unchanged freezing stress tolerance, significant ultrastructural changes were observed in field-sampled cells and in response to the artificial cold acclimation treatment: organelles such as the endoplasmic reticulum and thylakoids of the chloroplast showed distinct membrane bloating. Still, in the field samples, the Golgi apparatus appeared in an impeccable condition, and multivesicular bodies were less frequently observed suggesting a lower overall stress strain. The observed ultrastructural changes in winter and after cold acclimation are interpreted as cytological adjustments to winter or a resting state but are not related to frost hardening as Micrasterias cells were unable to improve their freezing stress tolerance.
PMID: 34304308