Isolation and functional characterization of salt-stress induced RCI2-like genes from Medicago sativa and Medicago truncatula

Radish is a kind of moderately salt-sensitive vegetable. Salt stress seriously decreases the yield and quality of radish. The plasma membrane Na+/H+ antiporter protein Salt Overly Sensitive 1 (SOS1) plays a crucial role in protecting plant cells against salt stress, but the biological function of the RsSOS1 gene in radish remains to be elucidated. In this study, the RsSOS1 gene was isolated from radish genotype ‘NAU-TR17’, and contains an open reading frame of 3414 bp encoding 1137 amino acids. Phylogenetic analysis showed that RsSOS1 had a high homology with BnSOS1, and clustered together with Arabidopsis plasma membrane Na+/H+ antiporter (AtNHX7). The result of subcellular localization indicated that the RsSOS1 was localized in the plasma membrane. Furthermore, RsSOS1 was strongly induced in roots of radish under 150 mmol/L NaCl treatment, and its expression level in salt-tolerant genotypes was significantly higher than that in salt-sensitive ones. In addition, overexpression of RsSOS1 in Arabidopsis could significantly improve the salt tolerance of transgenic plants. Meanwhile, the transformation of RsSOS1△999 could rescue Na+ efflux function of AXT3 yeast. In summary, the plasma membrane Na+/H+ antiporter RsSOS1 plays a vital role in regulating salt-tolerance of radish by controlling Na+ homeostasis. These results provided useful information for further functional characterization of RsSOS1 and facilitate clarifying the molecular mechanism underlying salt stress response in radish.

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Genome-wide identification and expression profiling of glutathione S-transferase family under multiple abiotic and biotic stresses in Medicago truncatula L.

PLoS ONE ◽

10.1371/journal.pone.0247170 ◽

2021 ◽

Vol 16 (2) ◽

pp. e0247170

Author(s):

Md. Soyib Hasan ◽

Vishal Singh ◽

Shiful Islam ◽

Md. Sifatul Islam ◽

Raju Ahsan ◽

...

Keyword(s):

Medicago Truncatula ◽

Expression Profiling ◽

Developmental Stages ◽

Functional Characterization ◽

Drought Treatment ◽

Specific Expression ◽

Abiotic And Biotic Stresses ◽

Biotic Stresses ◽

Genome Wide

Glutathione transferases (GSTs) constitute an ancient, ubiquitous, multi-functional antioxidant enzyme superfamily that has great importance on cellular detoxification against abiotic and biotic stresses as well as plant development and growth. The present study aimed to a comprehensive genome-wide identification and functional characterization of GST family in one of the economically important legume plants—Medicago truncatula. Here, we have identified a total of ninety-two putative MtGST genes that code for 120 proteins. All these members were classified into twelve classes based on their phylogenetic relationship and the presence of structural conserved domain/motif. Among them, 7 MtGST gene pairs were identified to have segmental duplication. Expression profiling of MtGST transcripts revealed their high level of organ/tissue-specific expression in most of the developmental stages and anatomical tissues. The transcripts of MtGSTU5, MtGSTU8, MtGSTU17, MtGSTU46, and MtGSTU47 showed significant up-regulation in response to various abiotic and biotic stresses. Moreover, transcripts of MtGSTU8, MtGSTU14, MtGSTU28, MtGSTU30, MtGSTU34, MtGSTU46 and MtGSTF8 were found to be highly upregulated in response to drought treatment for 24h and 48h. Among the highly stress-responsive MtGST members, MtGSTU17 showed strong affinity towards its conventional substrates reduced glutathione (GSH) and 1‐chloro‐2,4‐dinitrobenzene (CDNB) with the lowest binding energy of—5.7 kcal/mol and -6.5 kcal/mol, respectively. Furthermore, the substrate-binding site residues of MtGSTU17 were found to be highly conserved. These findings will facilitate the further functional and evolutionary characterization of GST genes in Medicago.

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