Studies on expression analysis of DREB and IGS gene in sugarcane under water stress condition with semi-quantitative RT-PCR

Abstract

Drought stress is a major abiotic constraint limiting sugarcane productivity, necessitating the identification of reliable molecular markers for drought tolerance. The present study investigated the expression patterns of dehydration-responsive element-binding (DREB) and indole-3-glycerol phosphate synthase (IGS) genes in sugarcane under drought stress using semi-quantitative RT-PCR. Twenty-two sugarcane genotypes were subjected to water deficit at the grand growth stage by withholding irrigation for 14 days, with well-watered plants serving as controls. Soil moisture content and relative leaf water content confirmed effective stress imposition. Gene expression analysis revealed significant genotype-dependent variation, with drought-tolerant genotypes showing strong upregulation of both DREB and IGS genes compared to sensitive lines. Enhanced DREB expression indicated activation of ABA-independent transcriptional stress-response pathways, while increased IGS expression suggested involvement in indole metabolism, auxin-mediated root adaptation, and stress-associated metabolic regulation. Genotypes CoM 22016, CoM 22018, Co 86032, CoM 0265, PDN 15012 and Co 740 consistently exhibited higher expression of both genes, correlating with superior drought adaptability. The study highlights the coordinated role of physiological and molecular mechanisms in sugarcane drought tolerance and identifies DREB and IGS as potential molecular markers for use in drought-resilient breeding programs.