Drought tolerance mechanisms and their molecular basis

Verslues, Paul E.; Bhaskara, Govinal Badiger; Kesari, Ravi; Nagaraj, Kumar M.

doi:10.1002/9781118764374.ch2

Cited by 16 publications

(16 citation statements)

References 158 publications

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“…At 56 DAT, there were no differences among cultivars, and Fv/Fm was altered by water deficit in only two cultivars. The smallest variation of this characteristic at 56 days compared with 28 DAT may have been due to the osmotic adjustment process whereby plants, under water deficit conditions, actively accumulate sugars, organic acids and ions in the cell cytosol to decrease the osmotic potential and therefore maintain the water potential and turgor of the cells near their optimum level (VERSLUES et al, 2014;LAKSMANAN;ROBINSON, 2014).…”

Section: Discussionmentioning

confidence: 99%

Water stress effects on chlorophyll fluorescence and chlorophyll content in sugarcane cultivars with contrasting tolerance

2018

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One way to minimize the impacts caused by water deficit (WD) in agriculture is the use of tolerant cultivars. The physiological evaluation of plants through the potential quantum efficiency of photosystem II (Fv/Fm) and estimated chlorophyll content (SPAD index) can be an effective tool in the selection and recommendation of water deficit-tolerant cultivars. Within this context, the aim of this study was to evaluate the physiological responses of sugarcane cultivars classified as tolerant or susceptible to water deficit. The experiment was carried out near the city of Jaú, SP, Brazil in a greenhouse, between July and December 2013. The experimental design was completely randomized in a 4 x 2 factorial arrangement, with four replications. We studied four sugarcane cultivars: RB72454, RB855453 (prone to WD), SP81-3250 and SP83-2847 (WD-tolerant) in two water management regimes (with and without deficit). WD reduced stems dry mass of all cultivars, however, the greatest decreases were observed in susceptible cultivars to WD, where the decrease was 58.3 and 74.5% for cultivars RB855443 and RB72454, respectively. As for the SP81-3250 and SP83-2847 cultivars (tolerant), the reduction was 44.1 and 47.7%, respectively. For water deficit-tolerant cultivars, there was lower reduction in potential quantum efficiency of photosystem II and SPAD index; therefore, the physiological characteristics (Fv/Fm and SPAD index) are features that can aid the identification and selection of water deficit tolerant cultivars, and also help the recommendation of these cultivars for harsh environments, minimizing the effects of water deficit on stem yield on the sugarcane crop.

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Section: Discussionmentioning

confidence: 99%

Water stress effects on chlorophyll fluorescence and chlorophyll content in sugarcane cultivars with contrasting tolerance

2018

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“…We therefore can conclude that, stomata patterning is only one of the traits 511 contributing to the optimization of WUE. A large array of molecular and physiological 512 reactions is indeed known to contribute to tolerance to drought stress (Krasensky & Jonak,513 2012; Verslues et al, 2013). The close vicinity of the chromosome 2 QTL to a non-514 synonymous mutation in a gene encoding an LEA protein, known to act as a chaperone when 515 cells dehydrate, suggests one possible mechanism by which WUE might be optimized 516 independently of stomata size and density (Candat et al, 2014;Eriksson, Kutzer, Procek, 517 the presence of drought stress or in nutrient acquisition in the root are also among the 519 physiological mechanism that appear to have contributed to improve drought stress tolerance 520 in this species (Campitelli et al, 2016;Kesari et al, 2012).…”

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Natural variation in stomata size contributes to the local adaptation of water-use efficiency in Arabidopsis thaliana

Dittberner

Korte

Mettler‐Altmann

et al. 2018

Preprint

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A b s t r a c t Stomata control gas exchanges between the plant and the atmosphere. How natural variation in stomata size and density contributes to resolve trade-offs between carbon uptake and water-loss in response to local climatic variation is not yet understood. We developed an automated confocal microscopy approach to characterize natural genetic variation in stomatal patterning in 330 fully-sequenced Arabidopsis thaliana ecotypes collected throughout the European range of the species. We compared this to variation in water-use efficiency, measured as carbon isotope discrimination (δ 13 C). Combined with public genomic and environmental resources, we show that genetic variation for stomata size and density is pervasive in Arabidopsis thaliana. A positive correlation between stomata size and δ 13 C further shows that this variation has consequences on water-use efficiency. Genome-wide association analyses reveal that many loci of small effect contribute not only to variation in stomata patterning but also to its co-variation with carbon uptake parameters. Yet, we report two novel QTL affecting δ 13 C independently of stomata patterning. This suggests that, in A. thaliana, both morphological and physiological variants contribute to genetic variance in water-use efficiency. Patterns of regional differentiation and co-variation with climatic parameters indicate that natural selection has contributed to shape some of this variation, especially in Southern Sweden, where water availability is comparatively more limited in Spring.

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“…Many hypotheses of how plants sense water loss center on detection of mechanical stimuli generated by loss of turgor and cell shrinkage. This includes changes in membrane shape or disruption of cell wall-cell membrane connections possibly detected by proteins, such as mechanosensitive channels or receptor-like kinases that bind cell wall components (4)(5)(6)(7)(8)(9). Proteins that induce or detect membrane curvature are known in mammalian cells (10) but have been little considered in plants.…”

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At14a-Like1 participates in membrane-associated mechanisms promoting growth during drought in Arabidopsis thaliana

Kumar

Hsieh

Verslues

2015

Proc. Natl. Acad. Sci. U.S.A.

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Limited knowledge of how plants regulate their growth and metabolism in response to drought and reduced soil water potential has impeded efforts to improve stress tolerance. Increased expression of the membrane-associated protein At14a-like1 (AFL1) led to increased growth and accumulation of the osmoprotective solute proline without negative effects on unstressed plants. Conversely, inducible RNA-interference suppression of AFL1 decreased growth and proline accumulation during low water potential while having no effect on unstressed plants. AFL1 overexpression lines had reduced expression of many stress-responsive genes, suggesting AFL1 may promote growth in part by suppression of negative regulatory genes. AFL1 interacted with the endomembrane proteins protein disulfide isomerase 5 (PDI5) and NAI2, with the PDI5 interaction being particularly increased by stress. PDI5 and NAI2 are negative regulatory factors, as pdi5, nai2, and pdi5-2nai2-3 mutants had increased growth and proline accumulation at low water potential. AFL1 also interacted with Adaptor protein2-2A (AP2-2A), which is part of a complex that recruits cargo proteins and promotes assembly of clathrin-coated vesicles. AFL1 colocalization with clathrin light chain along the plasma membrane, together with predictions of AFL1 structure, were consistent with a role in vesicle formation or trafficking. Fractionation experiments indicated that AFL1 is a peripheral membrane protein associated with both plasma membrane and endomembranes. These data identify classes of proteins (AFL1, PDI5, and NAI2) not previously known to be involved in drought signaling. AFL1-predicted structure, protein interactions, and localization all indicate its involvement in previously uncharacterized membrane-associated drought sensing or signaling mechanisms.E ven relatively mild drought that causes reduced soil water potential (ψ w ) can result in dramatically reduced plant growth and agricultural productivity. Physiological analyses have shown that plant growth is actively down-regulated during drought and is not limited by carbon supply (1-3). Reductions of growth help ensure survival by conserving water but can be undesirable for agriculture, as plant productivity is reduced more than need be if growth were less sensitive to changes in water status (3). Also, specific metabolic pathways, such as proline metabolism, are stress regulated and contribute to drought tolerance.The sensing and signaling mechanisms controlling growth and metabolic responses to drought remain unclear. Many hypotheses of how plants sense water loss center on detection of mechanical stimuli generated by loss of turgor and cell shrinkage. This includes changes in membrane shape or disruption of cell wall-cell membrane connections possibly detected by proteins, such as mechanosensitive channels or receptor-like kinases that bind cell wall components (4-9). Proteins that induce or detect membrane curvature are known in mammalian cells (10) but have been little considered in plants. Also, in analogy to mammal...

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Drought tolerance mechanisms and their molecular basis

Cited by 16 publications

References 158 publications

Water stress effects on chlorophyll fluorescence and chlorophyll content in sugarcane cultivars with contrasting tolerance

Water stress effects on chlorophyll fluorescence and chlorophyll content in sugarcane cultivars with contrasting tolerance

Natural variation in stomata size contributes to the local adaptation of water-use efficiency in Arabidopsis thaliana

At14a-Like1 participates in membrane-associated mechanisms promoting growth during drought in Arabidopsis thaliana

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