29.レタスDELLA遺伝子の特徴付け(口頭発表)

概要

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We isolated two cDNAs (LsDELLA1 and LsDELLA2) encoding DELLA proteins (570 and 591amino acids, respectively), negative regulators of gibberellin (GA) signals, from Lettuce (Lactuca sativa L. cv. Grand Rapids). We have also identified a cDNA derived from a splicing-variant mRNA of LsDELLA1 (LsDELLA1sv). LsDELLA1sv mRNA encoded a truncated protein (357amino acids) missing C-terminus GRAS domain as a result of frame-shift caused by 82bp splicing. In this study, we characterized the LsDELLA1, 2 and 1sv transcripts. We first isolated two lettuce cDNAs (LsGID1a and LsGID1b) encoding GID1s, soluble gibberellin receptors, for binding assay and pull-down assay. Binding assay and pull-down assay showed that both of recombinant LsGID1a and b bound physiologically active GA in the presence of recombinant LsDELLA1 or 2, and interacted to the recombinant LsDELLAs. The recombinant LsDELLA1sv, truncated LsDELLA1, also interacted to the recombinant LsGID1s, accompanied with GA binding. QRT-PCR analysis indicated that transcript levels of LsDELLA1 and LsDELLA2 were higher in early-stage flowering organs than those in other organs examined. On the other hands, transcript levels of LsDELLA1sv were higher not only in early-stage and but also in late-stage flowering organs. We will show the phenotype of transgenic Arabidopsis plants expressing LsDELLA1, 2 or LsDELLA1sv.
2009-10-06