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Structural and functional characterization of two novel durum wheat annexins genes in response to abiotic stress
Abiotic stress results in massive loss of crop productivity throughout the world. Understanding of the plant gene regulatory mechanisms involved in stress responses are very important. Annexins are a conserved multigene family of calcium-dependent, phospholipid binding proteins with suggested functions in response to environmental stresses and signaling during plant growth and development. Annexins function to counteract oxidative stress, maintain cell redox homeostasis, and enhance drought tolerance. A full-length cDNA of two genes (TdAnn6 and TdAnn12) encoding annexin proteins were isolated and characterized from Tunisian durum wheat varieties (cv. Mahmoudi). Analyses of the deduced proteins encoded by annexin cDNAs (TdAnn6 and TdAnn12) indicate the presence of the characteristic four repeats of 70 to 75 amino acids and the motifs proposed to be involved in Ca2+ binding. Gene expression patterns obtained by real-time PCR revealed differential temporal and spatial regulation of the two annexin genes in durum wheat under different abiotic stress conditions such as salt (NaCl 150 mM), osmotic (10% PEG 8000), ionic (LiCl 10 mM), oxidative (H2O2), abscisic acid (100 µM), salicylic acid (10 mM), cold (4°C) and Heat (37°C). The two annexin genes were not regulated by heavy metal stress (CdCl2 150 µM). Moreover, heterologous expression of TdAnn6 and TdAnn12 in yeast improves its tolerance to abiotic stresses suggesting its involvement in theses stress tolerance mechanisms. Taken together, our results show that the two newly isolated wheat annexin might play an active role in modulating the plant cell responses to abiotic stress responses.
FP17212 Accepted 12 November 2017
© CSIRO 2017