Expression pattern of drought stress marker genes in soybean roots under two water deficit systems

Abstract

The study of tolerance mechanisms for drought stress in soybean is fundamental to the understanding and development of tolerant varieties. Using in silicoanalysis, four marker genes involved in the classical ABA-dependent and ABA-independent pathwaysofdrought response were identified in theGlycine maxgenomein the present work. The expression profiles of the marker genesERD1-like, GmaxRD20A-like, GmaxRD22-likeand GmaxRD29B-like were investigated by qPCR in root samples of drought sensitive and tolerant soybean cultivars (BR 16 and Embrapa 48, respectively), submitted to water deficit conditions in hydroponic and pot-based systems. Among the four putative soybean homologs toArabidopsisgenes investigated herein, onlyGmaxRD29B-like was not regulated by water deficit stress. Distinct expression profiles and different induction levels were observed among the genes, as well as between the two drought-inducing systems. Our results showed contrasting gene expression responses for the GmaxRD20A-like and GmaxRD22-like genes. GmaxRD20A-like was highly induced by continuous drought acclimating conditions, whereas GmaxRD22-like responses decreased after abrupt water deprivation. GmaxERD1-like showed a different expression profile for the cultivars in each system. Conversely, GmaxRD20A-like and GmaxRD22-like genes exhibited similar expression levels in tolerant plants in both systems. © 2012, Sociedade Brasileira de Genética.