Inducing dehydration tolerance in rice by regulated expression of genes for transcription factors

摘要

Drought, salinity, and cold cause a reduction in the growth and productivity of crops. Most of the genes that respond to drought, salinity, and cold stress are also induced by exogenous abscisic acid (ABA). Transcription factors CBF/DREBs and ABFs arerelated to ABA-independent and ABA-dependent stress-signaling pathways in Arabidopsis, respectively. They are known to bind cis-regulatory elements, DREs, and ABREs and induce the expression of dehydration-related genes, including cor15a, rd29A, kin1, kin2,ere10, and cor6.6, making plants tolerant of such a stress. To make dehydration-tolerant transgenic rice, we have designed several constructs that can drive expression of either CBF3 (= DREB1A) or ABFs, transcription factors that respond to dehydration. We also made a fusion gene in which the two cDNAs encoding CBF3 and ABFs were ligated in a frame mediated by the 2A sequence from FMDA, By transactivation assay using the particle bombardment method, we validated that CBF3/DREB1A from Arabidopsis induces the cor15a promoter that contains DRE and ABRE in rice, suggesting that the CBF3/DREB1A and cor15a promoter can work with a rice transcription apparatus. Several transgenic rice plants for each construct were produced by cocultivating embryogenic calli with Agrobacterium, Analysis of the plants is under way.