Isolation and molecular characterization of genes associated with shoot regeneration of mustard (Brassica juncea) in vitro

Abstract

The process of shoot regeneration is very complex and the regulatory mechanism is not well understood. The main aims of this study are to identify and characterize genes associated with shoot regeneration in vitro. Using mRNA differential display, 87 partial cDNA sequences were identified. The full-length cDNAs of six members (BjGSTF1-6) of the glutathione S-transferase (GST) gene and a Raf-like MAPKKK (SRKKK) from mustard were also isolated. Characterization of these cDNAs showed that expression of these genes might be regulated both spatially and temporally, and in response to a variety of exogenous stimuli. Transgenic studies indicated that GST was important to shoot regeneration and tolerance to paraquat and HgCl2, while SRKKK might be involved in glutathione and/or jasmonate related signaling pathway. Functional analysis of the BjGSTF2 promoter indicated that GST expression might be regulated transcriptionally at the promoter during plant growth and development and in response to external stimuli.