Functional Characterization of Cotton GaMYB62L, a Novel R2R3 TF in Transgenic Arabidopsis

<div><p>Drought stress can trigger the production of ABA in plants, in response to adverse conditions, which induces the transcript of stress-related marker genes. The R2R3 MYB TFs are implicated in regulation of various plants developmental, metabolic and multiple environmental stress responses. Here, a R2R3-MYB cloned gene, <i>GaMYB62L</i>, was transformed in Arabidopsis and was functionally characterized. The <i>GaMYB62L</i> protein contains two SANT domains with a conserved R2R3 imperfect repeats. The <i>GaMYB62L</i> cDNA is 1,017 bp with a CDS of 879, encodes a 292-residue polypeptide with MW of 38.78 kD and a pI value of 8.91. Overexpressed <i>GaMYB62L</i> transgenic Arabidopsis have increased proline and chlorophyll content, superior seed germination rate under salt and osmotic stress, less water loss rate with reduced stomatal apertures, high drought avoidance as compared to WT on water deprivation and also significant plant survival rates at low temperature. In addition, overexpressed <i>GaMYB62L</i> lines were more sensitive to ABA mediated germination and root elongation assay. Moreover, ABA induced <i>GaMYB62L</i> overexpression, enhanced the expression of ABA stress related marker genes like <i>RD22</i>, <i>COR15A</i>, <i>ADH1</i>, and <i>RD29A</i>. Together, overexpression of <i>GaMYB62L</i> suggested having developed better drought, salt and cold tolerance in transgenic Arabidopsis and thus presented it as a prospective candidate gene to achieve better abiotic stress tolerance in cotton crop.</p></div>