Unraveling abiotic stress tolerance mechanisms – getting genomics going

Bohnert, Hans J.; Gong, Qingqiu; Li, Pinghua; Ma, Shisong

doi:10.1016/j.pbi.2006.01.003

Cited by 383 publications

(235 citation statements)

References 81 publications

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“…In particular, the Arabidopsis cytosolic ascorbate peroxidase gene (APX1) has been shown not only to be heat upregulated, but also to contain a functional heat shock element (HSE) in its 5'-promoter region. As heat stress tolerance is a polygenic trait (controlled by different sets of genes), various different components of tolerance are critical at different developmental stages or in different tissues of plant; hence, it shows spacio-temporal mechanism and regulation [77]. Thus, the use of genetic stocks with different degrees of heat tolerance, correlation and co-segregation analyses, molecular biology techniques and molecular markers to identify tolerance QTLs are promising approaches to dissect the genetic basis of plant's thermotolerance [78].…”

Section: Mechanisms Of Thermotolerancementioning

confidence: 99%

Heat Stress Responses and Thermotolerance

Hemantaranjan¹,

Bhanu²,

Singh³

et al. 2014

APAR

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climate change is that most agricultural regions will experience additional extreme environmental fluctuations [2]. Direct injuries due to high temperatures include protein denaturation and aggregation and increased fluidity of membrane lipids. Indirect or slower heat injuries include inactivation of enzymes in chloroplast and mitochondria, inhibition of protein synthesis, protein degradation and loss of membrane integrity [3]. Heat stress also affects the organization of microtubules by splitting and/or elongation of spindles, formation of microtubule asters in mitotic cells and elongation of phragmoplast microtubules [4].The unfavourable effects of heat stress can be mitigated by developing crop plants with improved thermotolerance using an assortment of genetic approaches. For this reason, a thorough understanding of physiological responses of plants to high temperature, mechanisms of heat tolerance and possible strategies for improving crop thermotolerance is crucial. Acquiring thermotolerance is a lively progression by which considerable amounts of plant resources are diverted to structural and functional maintenance to escape damages caused by heat stress. Although biochemical and molecular aspects of thermotolerance in plants are relatively well understood, additional studies focused on phenotypic flexibility and assimilate partitioning under heat stress and factors modulating crop heat tolerance are imperative. High temperature during seed germination may slow down or totally inhibit germination, depending on plant species and the intensity of the stress [5]. At later stages, high IntroductionFuture global climate change, with predicted 1.5-5.8 °C increases in temperatures by 2100 has to cause heat stress to create threats to agricultural production [1]. An increase in global temperature ranging from 1.1 to 6.4 °C depending on global emissions scenarios, will accompany the rises in atmospheric CO 2 . Though high temperature and other abiotic stresses are clearly limiting factors for crops cultivated on marginal lands, crop productivity far and wide is often at the mercy of random environmental fluctuations. Existing assumption about global Heat Stress Responses and Thermotolerance AbstractThe rising ambient temperature by plant cells is crucial for the timely activation of various molecular defences before the appearance of heat damage. The heat-threshold level varies considerably at different developmental stages. With a view to survive under heat stress, mechanisms of regulation at the molecular level enable plants to prosper. Traditional breeding contributed for improving heat tolerance meagrely. The genetic transformation approach needs to be accelerated that can mitigate harmful effects by developing improved thermotolerance of crop plants. In this background, a thorough understanding of physiological responses of plants to high temperature, mechanisms of heat tolerance and possible strategies is vital. Temperature changes are sensed through cellular responses due to signal transduction into the c...

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Section: Mechanisms Of Thermotolerancementioning

confidence: 99%

Heat Stress Responses and Thermotolerance

Hemantaranjan¹,

Bhanu²,

Singh³

et al. 2014

APAR

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“…To some extent, the advent of genomics has shifted away the focus on abiotic stress biology in species that show natural tolerance. Essential requisites for abiotic stress are being assembled on a genome-wide scale in an anthological way rather than by hypothesis-driven experimentation (Bohnert et al, 2006). This information is necessary for the elucidation of abiotic stress interactive pathways.…”

Section: Global Expression Profiling -Abiotic Stressmentioning

confidence: 99%

Genetic approaches towards overcoming water deficit in plants - special emphasis on LEAs

Khurana

Vishnudasan

Chhibbar

2008

Physiol Mol Biol Plants

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Water deficit arises as a result of low temperature, salinity and dehydration, thereby affecting plant growth adversely and making it imperative for plants to surmount such situations by acclimatizing/adapting at various levels. Water deficit stress results in significant changes in gene expression, mediated by interconnected signal transduction pathways that may be triggered by calcium, and regulated via ABA dependent and/or independent pathways. Hence, adaptation of plants to such stresses involves maintaining cellular homeostasis, detoxification of harmful elements and also growth alterations. Stress in general cause excess production of reactive oxygen species (ROS) and the plants overcome the same by either preventing the accumulation of ROS or by eliminating the ROS formed. Ion homeostasis includes processes such as cellular uptake, sequestration and export in conjunction with long distance transport. Requisite amounts of osmolytes are hence synthesized under stress to maintain turgor along with maintaining the macromolecular structures and also for scavenging ROS. Another noteworthy response is the accumulation of novel proteins, including enzymes involved in the biosynthesis of osmoprotectants, heat-shock proteins (HSPs), late embryogenesis abundant (LEA) proteins, antifreeze proteins, chaperones, detoxification enzymes, transcription factors, kinases and phosphatases. The LEAs belong to a redundant protein family and are highly hydrophilic, boiling-soluble, non-globular and therefore have been defined and classified accordingly. The precise function of LEAs is still unknown, but substantial evidence indicates their involvement in dessication tolerance as the expression of LEAs confers increased resistance to stress in heterologous yeast system and also significantly improves water deficit tolerance in transgenic plants. Genetic manipulation of plants towards conferring abiotic stress tolerance is a daunting task, as the abiotic stress tolerance mechanism is highly complex and various strategies have been exploited to address and evaluate the stress tolerance mechanism, and the molecular responses to water deficit via complex signaling networks. Genomic technologies have recently been useful in integrating the multigenicity of the plant stress responses through, transcriptomics, proteomics and metabolite profilling and their interactions. This review deals with the recent developments on genetic approaches for water stress tolerance in plants, with special emphasis on LEAs.

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“…Despite this complexity, most salt-tolerant cultivars seem to posses only a few of these mechanisms, signifying the prospects for developing highly tolerant rice varieties through combining superior alleles of genes controlling these traits. Recent advances in molecular biology and genomics have led to a more detailed understanding of the genes and pathways involved in the salt stress response in rice, including those involved in ion transport and homeostasis, osmoregulation, and oxidative stress protection (Blumwald et al 2000;Mäser et al 2002;Garciadeblás et al 2003;Chinnusamy et al 2004;Horie and Schroeder 2004;Nakayama et al 2005;Bohnert et al 2006;Rodriguez-Navarro and Rubio 2006;Sahi et al 2006;Martinoia et al 2007;Munns and Tester 2008;Singh and Flowers 2010) The vast genetic variability reported in rice in response to salinity makes it amenable to genetic manipulation to further enhance its tolerance (Akbar et al 1972;Flowers and Yeo 1981). Breeders have long made use of the high level of salinity tolerance in landraces like Nona Bokra and Pokkali.…”

Section: Introductionmentioning

confidence: 99%

Characterizing the Saltol Quantitative Trait Locus for Salinity Tolerance in Rice

Thomson

Ocampo

Egdane

et al. 2010

Rice

423

370

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This study characterized Pokkali-derived quantitative trait loci (QTLs) for seedling stage salinity tolerance in preparation for use in marker-assisted breeding. An analysis of 100 SSR markers on 140 IR29/Pokkali recombinant inbred lines (RILs) confirmed the location of the Saltol QTL on chromosome 1 and identified additional QTLs associated with tolerance. Analysis of a series of backcross lines and near-isogenic lines (NILs) developed to better characterize the effect of the Saltol locus revealed that Saltol mainly acted to control shoot Na + /K + homeostasis. Multiple QTLs were required to acquire a high level of tolerance. Unexpectedly, multiple Pokkali alleles at Saltol were detected within the RIL population and between backcross lines, and representative lines were compared with seven Pokkali accessions to better characterize this allelic variation. Thus, while the Saltol locus presents a complex scenario, it provides an opportunity for markerassisted backcrossing to improve salt tolerance of popular varieties followed by targeting multiple loci through QTL pyramiding for areas with higher salt stress.

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Unraveling abiotic stress tolerance mechanisms – getting genomics going

Cited by 383 publications

References 81 publications

Heat Stress Responses and Thermotolerance

Heat Stress Responses and Thermotolerance

Genetic approaches towards overcoming water deficit in plants - special emphasis on LEAs

Characterizing the Saltol Quantitative Trait Locus for Salinity Tolerance in Rice

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