Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Comparative proteomics and metabolomics studies in the xero halophyte Salvadora Persica L for elucidation of drought tolerance mechanisms

Auteur : Rangani Jaykumar Rameshbhai

Université de soutenance : Academy of Scientific and Innovative Research (AcSIR)

Grade : Doctor of Philosophy (PhD) 2021

Résumé
The xero-halophyte Salvadora persica L. is well adapted to survive in arid and semiarid areas of the world. With an aim to evaluate its drought tolerance mechanisms, alterations in growth, photosynthesis, ion homeostasis, chlorophyll fluorescence, ROS and antioxidative defense system, metabolite dynamics and alterations in chloroplast protein were examined in S. persica subjected to drought stress and recovery. The results showed that there was a significant reduction in growth, photosynthesis, and chlorophyll content, without any significant alterations in leaf RWC and Fv/Fm ratio. Upon recovery, the growth, chlorophyll, and photosynthesis were recovered to control level within 7 d. The ionomics studies revealed that S. persica was able to maintain Na+ , K+ , Ca2+, B, Cu2+, Fe2+, Mo, and Zn2+ content in leaf during drought period. Unaffected MDA and electrolyte leakage suggested that effective coordination of enzymatic and non-enzymatic antioxidant scavenge stress generated ROS. The metabolite profiling identified a total of 68 metabolites in S. persica leaf, including organic acids, amino acids, sugars, sugar alcohols, hormones, and polyphenols. The results showed that higher cellular osmolality under drought stress were accompanied by accumulations of several osmoprotectants like sugars, polyols, organic acids, and amino acids. In addition, efficient stress signaling was provided by ABA and JA to achieve early drought tolerance. Moreover, upregulation of phenyl alanine metabolism provides antioxidants like coumarin, gallic acid, and chlorogenic acid for combating against drought-induced oxidative stress. Thylakoid protein complex analysis revealed that PSII-LHCII supercomplexes and PSI, PSII dimer, and ATP synthase were significantly increased under drought stress and recovery condition. In addition, stable fates of core proteins D1 and D2 under drought and recovery condition enables functional maintenance of PSII core complex. The increased association of PSI and PSII enables the efficient quenching of excess energy by PSI from PSII. The knowledge obtained from this study will enable to formulate strategy for the development of drought tolerance in crop plants using genetic engineering and breeding approaches

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