Abstract:

【Objective】 Cucumber chlorophyll-deficient mutant is an ideal material for studies on the photosynthetic system and genetic breeding. To make clear on the mechanism of the leaf colour transformation in yellow leaf mutant will provide a theoretical basis for quantitative trait loci gene mapping and gene cloning. 【Method】 A cucumber chlorophyll-deficient mutant named 9110Gt and its wild type named 9110G were used as materials in this study. The photosynthetic pigment components, contents and Pchl contents in 9110Gt and 9110G were analysed. cDNA-AFLP and cDNA-Ad-SRAP were employed to detect the differentially expressed genes. 【Result】 Spectral analysis showed that there was no significant difference in the pigment components between 9110Gt and 9110G, but the contents of photosynthetic pigment and protochlorophyll in 9110Gt were lower than in wild type in yellow period. Nine candidate transcript derived fragments (TDFs) were obtained. The candidate transcript derived fragments had highly identities with cucumber mitochondrial and chloroplast genome sequence. 【Conclusion】 It was concluded that there was a blockage in the protochlorophyllide biosynthesis, then leading to lower chlorophyll content and make changes in the proportion of photosynthetic pigment of mutant. The leaf colour mutant was may be due to gene mutations in chloroplast development and chlorophyll biosynthesis.

Key words: cucumber (Cucumis sativus L.), chlorophyll-deficient mutant, photosynthetic pigment, differential expression sequence