Abstract

Moisture deficit stress, one of the abiotic stresses, affects sugarcane growth and development and reduces cane and sugar yields. Transcription Factors (TFs) are master regulatory proteins in all living cells which have the capability of activating or repressing transcription of stress responsive genes in order to activate the stress tolerance mechanism. Study of expression profiles of TF genes which regulate the expression of stress responsive genes help to elucidate the regulatory biology of stress tolerance. Expression of 17 sugarcane TF genes in moisture deficit stress sensitive and tolerant varieties under different moisture deficit stress conditions were quantified in quantitative real-time PCR. Expression of seven TF genes namely, WRKY, NAC, bZIP, DREB, G2 like, Homeobox and TUB showed significant difference between the stress tolerant and susceptible varieties under both moderate and severe moisture deficit stress conditions. In stress tolerant variety, of these seven TF genes, bZIP showed highest expression both under moderate (22.39 fold) and severe stress (13.45 fold) conditions than other TF genes. Expression of bZIP gene in moisture deficit stress susceptible variety was significantly low under moderate (1.09 fold) and severe (3.63 fold) moisture deficit stress condition. GRAS TF gene under moderate stress condition (4 fold) and Homeobox gene under severe stress condition (6.06 fold) showed highest expressions than other TF genes in moisture stress susceptible variety. These differentially expressed TFs among the moisture stress tolerant and sensitive varieties hold promise for improving abiotic stress tolerance in sugarcane through their use as the potential candidate genes in marker assisted selection and in genetic transformation.

Key words: Transcription factors, moisture deficit stress, qRT- PCR, sugarcane.