| Summary: | 碩士 === 國立中興大學 === 生物科技學研究所 === 100 === 英文摘要
Viral diseases inflict severe economical losses in the production of cucurbit crops. Aside from the control of insect vectors by chemical or physical methods, the breeding and cultivation of virus-resistant varieties are among the most effective means for the management of viral diseases in cucurbits. Previous collaborative studies with Taiwan Agriculture Research Institute on the RNA virus-resistant wax-gourd variety, TVI4204, have identified a 14-3-3 family protein positively correlated to the virus-resistance phenotype. The 14-3-3 family genes have recently been shown to be involved in the pathogenesis of viruses in other plants, either enhancing or reducing the disease severity. To further explore the possible anti-viral functions in muskmelons, the 14-3-3 family protein genes, designated Cm14-3-3 genes, were cloned and characterized in this study. Degenerate primers were designed based on the consensus sequences of 14-3-3 family genes from different dicotyledonous plants and used to amplify the corresponding genes in muskmelons. Three different 14-3-3 family genes, #4, #15, and #39, have been identified. The full-length transcripts of these genes were further cloned by 5’- and 3’-RACE. Currently, #4, #15 and #39 have been fully sequenced and sub-cloned for over-expression in bacteria. The three Cm14-3-3 genes share less than 81 % nucleotide sequence similarities, demonstrating that there are at least three different Cm14-3-3 family genes present in muskmelon genome. These different Cm14-3-3 proteins have been expressed in Escherichia coli, purified, and used to raise specific antisera with potential applications in future breeding programs against viral diseases. The involvement of different Cm14-3-3 proteins in virus-resistance phenotype will further be analyzed by semi-quantitative PCR in different varieties of wax-gourd, squash, and muskmelon. It is expected that these 14-3-3 family proteins may serve as molecular markers for breeding programs and provide further insights into the mechanisms of resistance against viral infections.
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