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A study of soybeanvsp gene expression in transgenic Arabidopsis: Induction by methyl jasmonate
Abstract
Two genes, vspA and vspB2 encoding VSP$\alpha$ and VSP$\beta$, respectively, were isolated from soybean genomic libraries. The primary sequence determination revealed that the two genes contained two exons and three introns. The transcription start sites were also determined, and the TATA-box and the G-box motif were located. It was concluded, based upon the Southern blot hybridization analysis, that there are two copies of vspB gene (vspB1 and vspB2) and a single copy of vspA gene in the soybean genome. When intact vspB2 was transformed into tobacco, no vspB expression was observed as determined by immunogenic protein blotting. To closely examine vsp gene expression, the GUS reporter structural gene was connected to the vspA and vspB promoters. The fused DNAs were tested in transient expression systems. Both promoters were highly active in electroporated tobacco protoplasts even without any treatment to induce these genes. Methyl jasmonate treatment did not increase gene expression in the transient system, suggesting the constitutive expression level was near the maximum. Several attempts to suppress the constitutive gene expression by treating the tobacco suspension cells with lipoxygenase inhibitors (presumably to inhibit biosynthesis of jasmonic acid that may be triggered by apparent wounding resulting from the protoplasting) and by cocultivating the suspension cells with Agrobacteria (to transfer the promoter-gus constructs to cells without making protoplasts) were not successful. In transgenic Arabidopsis, methyl jasmonate treatment resulted in GUS expression in the leaf veins and the petioles. The vspA gene expression induced by methyl jasmonate was primarily localized in cells associated with the vascular system, as in soybean. The epidermal cells, however, were not competent to express vspA in Arabidopsis. Promoter deletions established that the G-box, which was previously shown to be sufficient for induction of vspB and potato proteinase inhibitor II gene by methyl jasmonate treatment in tobacco, was insufficient for induction by methyl jasmonate in Arabidopsis. Nucleotides further upstream from the G-box motif were needed to confer maximum level of vspA expression by methyl jasmonate.
Subject Area
Molecular biology
Recommended Citation
Rhee, Yoon, "A study of soybeanvsp gene expression in transgenic Arabidopsis: Induction by methyl jasmonate" (1994). ETD collection for University of Nebraska-Lincoln. AAI9425304.
https://digitalcommons.unl.edu/dissertations/AAI9425304