Monitoring transcriptomic changes in root tissue leading to develop drought stress tolerant plants: the smart way of plants protection from abiotic stresses

S. Rasheed; K. Bashir; J M KIM; M Ando; A Matsui; M Tanaka; M Seki

Climatic changes such as global surface temperature produce abiotic stresses. So, it is very important to understand the molecular mechanisms of plant response to drought. This research was aimed to develop transgenic plants overexpressing the genes in acetic acid biosynthesis pathway under the control of a promoter with low expression at normal condition and specifically inducible by drought stress in roots and shoots. Microarray analysis of Arabidopsis roots and shoots was performed at 0, 1, 3, 5, 7 and 9th day of drought stress treatment. Microarray data was analyzed on Gene Spring. Soil moisture content was measured. In roots, 47 genes were upregulated at least 4 times at 3, 5, 7 and 9th day of drought condition (Rasheed et al, 2017). Among these highly upregulated genes, PDC1 and ALDH2B7 were found to be good candidates showing inducible expression at early stages as well as during later stages of drought. Expression of drought inducible gene in the early time period of drought is fundamentally important to produce drought-tolerant plants. For this strategy upregulation of the TSPO gene by drought stress was observed. qPCR, as well as GUS analysis of the promoter, confirmed the up-regulation of TSPO by drought stress in Arabidopsis roots and shoots. Thus, the TSPO promoter was used to drive drought-responsive expression of ALDH2B7 and PDC1. It was found that manipulation of acetic acid biosynthesis pathway was effective for enhancing drought stress tolerance (Kim et al. 2017). So, transgenic Arabidopsis plants expressing the acetic acid biosynthesis genes (AtPDC1 and/or AtALDH2B7) under the control of TSPO promoters were developed. These transgenic lines were found to be drought tolerant (Rasheed et al, 2018). qPCR analysis confirmed that the expression of PDC1 and ALDH2B7 was up-regulated, relative to WT plants, by drought stress in homozygous pTSPO-PDC1 and pTSPO-ALDH2B7 plants.