Abstract
Genes involved in defense systems against various types of stress particularly prone to alternative splicing in higher plants. We demonstrated that Arabidopsis splicing factors, atSR30 and atSR45a, are predicted to participate in regulation of the alternative splicing under high-light stress (Plant Cell Physiol. 48: 1036-1049, 2007). Here, we characterized T-DNA insertion mutants of atSR30 (KO-sr30) and atSR45a (KO-sr45a), and their double knockout mutants (WKO-sr30/sr45a). The transcript levels of atSR45a and atSR30 increased in KO-sr30 and KO-sr45a, respectively, under high-light stress. WKO-sr30/sr45a showed a dwarf phenotype, although KO-sr30 and KO-sr45a showed no difference in the phenotypes compared with wild-type plants. The transcript levels of various heat shock proteins (HSP), including HSP70, HSP17.4 and HSP101, decreased in WKO-sr30/sr45a. These results suggest that atSR30 and atSR45a coordinately function in the regulation of alternative splicing for genes involved in the induction of HSPs expression.
