佛手果形发育观察及果形相关基因表达分析

通过超景深显微镜和扫描电镜观察不同发育阶段的佛手（Citrus medica L. var. sarcodactylisSwingle）花芽形态，发现佛手指状部分并非发育自柱头，而是来自雌蕊子房。同时，在佛手中分离了CmsSUN20、CmsOFP7、CmsOFP12 和CmsYABBY5 等4 个果形相关基因的全长，与甜橙序列比对的相似性大于95%，构建进化树分析发现其与甜橙聚在一个分支。收集佛手和香橼（C. medica L.）果实发育相同阶段不同组织（叶片，花瓣，雌蕊，雄蕊）材料，以qRT-PCR 法分析了上述4 个基因的表达。结果表明CmsSUN20 在佛手雌蕊的表达显著高于香橼，在其他组织中差异不显著或相反，表明该基因可能与佛手雌蕊发育有关。CmsYABBY5 在佛手雌蕊和雄蕊中都显著高表达，而在叶片中却显著低表达，表明CmsYABBY5 有可能对佛手雌蕊和雄蕊发育有重要作用。而CmsOFP7 和CmsOFP12 在佛手叶片、雌蕊和雄蕊中均高表达，由于并非特异在雌蕊中高表达，所以可能并不对佛手果形建成起决定作用。

Fruit Morphogenesis Observation and Expression Analysis of Fruit-shaping related Genes in Fingered Citron

The fruit morphology of fingered citron（Citrus medica L. var. sarcodactylis Swingle）wastracked from the stage of flower primodium to mature fruit by super depth of field microscope andscanning electron microscope. It was found that fingered citron fruit fingers were originated from theovary rather than stigma. Meanwhile，CmsSUN20，CmsOFP7，CmsOFP12 and CmsYABBY5 were isolatedfrom fingered citron，which cDNA sequence showed 95% identity with those of sweet orange，as well asthe specific homologous relationships with sweet orange. Furthermore，the phylogenetic tree indicated thatthey were clustered with sweet orange in one group，respectively. The expression levels of those four genesin different tissues（leaf，petal，pistil and stamen）were analyzed by quantitative real-time PCR betweenthe two accessions. CmsSUN20 mRNA levels in fingered citron pistil were significantly higher than that inXiangyuan，or named as citron（C. medica L.），while slightly different in other tissues. This result indicated that CmsSUN20 gene may be associated with the fruit development of fingered citron.CmsYABBY5 gene was highly expressed in both pistil and stamen of fingered citron，but lowly expressedin leaf，implying CmsYABBY5 play a role during the development of pistil and stamen in fingered citron.Both the expression levels of CmsOFP7 and CmsOFP12 were higher in four tissues of fingered citronthan those in Xiangyuan，indicating the two genes have insignificant contribution to fruit shaping.