Investigation of the effects of overexpression of Novel_105 miRNA in contrasting potato cultivars during separate and combined drought and heat stresses

Potato (Solanum tuberosum L.) growth, development and production are sensitive to abiotic stress conditions, yet studies about investigation of stress response of potato plants in regulation of gene expression level are limited. The aim of this study was to identify the role of newly identified Novel_105 miRNA in contrasting potato cultivars (tolerant Unica and sensitive Russet Burbank) in response to heat, drought and combined heat and drought stresses using transgenic approach. Transgenic plants of Unica and Russet Burbank were generated with overexpression of pre-miRNA of Novel_105 and both wild type and transgenic T0 lines were subjected to stress. Physiological parameters (gaseous exchange, leaf temperature, chlorophyll content and relative water content) were observed along with biochemical parameters including proline, malondialdehyde and hydrogen peroxide. The overexpression of Novel_105 improved physiobiochemical functions of the both cultivars under single or combined stress conditions. The increase in Novel_105 miRNA expression was observed along with a decreased expression in its predicted target E3 ubiquitin-protein ligase XBAT35, that is responsible for cell death in potato. This is a preliminary study for the development of abiotic stress resilient potato cultivars proving the overexpression of Novel_105 miRNA increased abiotic stress tolerance presumably by repressing the expression of XBAT35 responsible from promoting cell death.