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Accueil du site → Doctorat → Australie → 2020 → Understanding the drought mechanism and designing strategies to mitigate drought stress in chickpea (Cicer arietinum L. )

RMIT University (2020)

Understanding the drought mechanism and designing strategies to mitigate drought stress in chickpea (Cicer arietinum L. )

BADHAN Sapna

Titre : Understanding the drought mechanism and designing strategies to mitigate drought stress in chickpea (Cicer arietinum L. )

Auteur : BADHAN Sapna

Université de soutenance : RMIT University

Grade : Doctor of Philosophy (PhD) 2020

Résumé partiel
Chickpea (Cicer arietinum L.) is a valued pulse crop that is consumed globally and is becoming increasingly important as agricultural productivity is predicted to drastically affected by climate change in coming years. Chickpea is also important as a nitrogen-fixing leguminous crop cultivated in rotation with cereal crops such as wheat and barley. This rotation strategy replenishes soil nitrogen whilst providing a break from pests and diseases. Abiotic stresses such as drought, salinity and heat are key factors limiting chickpea productivity worldwide. Drought is the major cause of the global decline in chickpea production. In plants, extreme drought conditions adversely affect growth, physiology and reproduction leading to reduced yield. To date, research has provided only limited insight into different genetic pathways related to drought tolerance/response. The aims of this thesis were first, to conduct RNA sequencing of leaf tissues from drought-tolerant and sensitive chickpea genotypes and identify candidate genes and pathways associated with drought tolerance/sensitivity. Secondly, to identify DNA methylation patterns that potentially regulate drought tolerance/sensitivity of selected chickpea genotypes. Thirdly, to perform gene knockout of selected drought tolerance associated genes using modern technique CRISPR/Cas9 DNA free editing to understand their role in drought tolerance. The first chapter of the thesis comprises the literature review discussing the challenges in chickpea production and examines the different mechanisms currently known to confer drought tolerance. The experimental chapter 2 describes the identification of drought tolerance associated genes by RNA sequencing of the leaf tissue from two contrasting chickpea genotypes under drought stress. In Chapter 2, to identify the genes/pathways that are differentially expressed under drought stress in the leaves of drought-tolerant and sensitive genotypes, leaf tissue from the shoot apical meristem developmental stage of drought-tolerant (ICC8261) and drought-sensitive (ICC283) genotypes were analysed using RNA sequencing. It was found that in the tolerant genotype, genes associated with ethylene response, MYB-related protein, xyloglucan endotransglycosylase, alkane hydroxylase MAH-like, BON-1-related, peroxidase 3-related, a cysteine-rich and transmembrane domain, vignain and mitochondrial uncoupling were explicitly upregulated, while in the sensitive genotype, the same genes were observed to be downregulated. The results confirm that the sensitive genotype was more affected by the drought stress compared to the tolerant genotype.

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