Citrus Lea promoter confers fruit-preferential and stress-inducible gene expression in Arabidopsis

Kim, Lee, J., Han, J.-A., Kim, C.-S. and Hur, Y. 2011. Citrus Lea promoter confers fruit-preferential and stress-inducible gene expression in Arabidopsis. Can. J. Plant Sci. 91: 459-466. A genomic clone encoding a group 5 late embryogenesis abundant protein (Lea5) was isolated from Citrus unshiu. Approximately 600 bp region upstream of the CuLea5 gene with putative cis-elements was fused to the beta-glucuronidase (GUS) gene in pBI121. The LeaP(600)::GUS construct was then introduced to Arabidopsis by Agrobacterium-mediated transformation. The transgenic Arabidopsis plants showed higher expression levels of GUS transcript in silique than in other tissues such as leaves and roots. The level of GUS transcripts increased according to silique development and the maximum was observed in yellowish silique. In addition, histochemical localization of GUS activity was detected only in the valve and septum defined as the fruit part of silique, but not in the seed and replum. The GUS expression in transgenic Arabidopsis leaves was enhanced by phytohormones, ABA and NAA, and abiotic stresses, cold and drought treatment. Thus, CuLea5 promoter confers the fruit-preferential and stress-responsive expression of a gene in plants.