2018年11月18日 星期日
中华猕猴桃品种‘Hort16A’果肉颜色形成的分子机制
Molecular mechanism of flesh color formation of Actinidia chinensis ‘Hort16A’
2018年 第27卷 第3期 页码[1-10]
摘要

对中华猕猴桃(Actinidia chinensis Planch.)品种‘Hort16A’果实发育过程(花后2~140 d及采后7~16 d)中果肉颜色的变化进行了观察,并对果实采后果肉中叶绿素和类胡萝卜素含量以及叶绿素和类胡萝卜素生物合成和降解相关基因的表达进行了研究。结果表明:花后2~140 d,中华猕猴桃品种‘Hort16A’的果肉为绿色;采后7~16 d,果肉颜色由绿变黄,果肉中叶绿素含量先升高后显著降低,类胡萝卜素含量无显著变化;类胡萝卜素/叶绿素比在采后16 d显著升高。采后12 d果肉中叶绿素生物合成相关基因中CAO1、GluTR1、LHCB1、LHCB2、CBR1和CLH1基因的相对表达量较采后7 d显著升高,之后显著降低;采后12~16 d果肉中叶绿素降解相关基因中PAO1、PAO2、PPH1、PPH2、PPH3、SGR1和SGR2基因的相对表达量总体上显著高于采后7 d,说明果肉中叶绿素含量降低是叶绿素的生物合成减少及其降解增加共同作用的结果。采后12~16 d果肉中类胡萝卜素生物合成相关基因中CrtISO1、ZISO1、LCYB2、CYP1和CHY1基因的相对表达量较采后7 d显著升高,类胡萝卜素降解相关基因中NCED1、NCED2、ZEP1和CCD2基因的相对表达量也显著升高,说明类胡萝卜素生物合成和降解达到平衡,导致类胡萝卜素含量无显著变化。相关性分析结果显示:中华猕猴桃品种‘Hort16A’果实采后果肉中叶绿素含量与PAO2基因的相对表达量在0.05水平上显著正相关,但与SGR1基因的相对表达量显著负相关;类胡萝卜素含量与LCYB2和CYP1基因的相对表达量在0.05水平上显著正相关;个别叶绿素和类胡萝卜素生物合成和降解相关基因相对表达量间的相关性在0.05或0.01水平上显著。研究结果显示:中华猕猴桃品种‘Hort16A’果实采后果肉中叶绿素的生物合成减少及其降解增加是导致叶绿素含量降低和果肉变黄的主要原因。

 

Abstract

Flesh color change during fruit development process (2-140 d after flowering and 7-16 d after harvesting) of Actinidia chinensis ‘Hort16A’ were observed, and contents of chlorophyll and carotenoid and expressions of their biosynthesis and degradation related genes from flesh of postharvest fruit were studied. The results show that flesh of A. chinensis ‘Hort16A’ is green during 2-140 d after flowering. During 7-16 d after harvesting, flesh color changes from green to yellow, chlorophyll content in flesh first increases and then decreases significantly, carotenoid content shows no significant variation, and carotenoid/chlorophyll ratio increases significantly at 16 d after harvesting. Relative expression levels of CAO1, GluTR1, LHCB1, LHCB2, CBR1, and CLH1 genes of chlorophyll biosynthesis related genes from flesh at 12 d after harvesting increase significantly compared with those from flesh at 7 d after harvesting, and then decrease significantly; relative expression levels of PAO1, PAO2, PPH1, PPH2, PPH3, SGR1, and SGR2 genes of chlorophyll degradation related genes from flesh at 12-16 d after harvesting are significantly higher than those from flesh at 7 d after harvesting in general, indicating that decrease of chlorophyll content in flesh is the combination effects of biosynthesis decrease of chlorophyll and its degradation increase. Relative expression levels of CrtISO1, ZISO1, LCYB2, CYP1, and CHY1 genes of carotenoid biosynthesis related genes from flesh during 12-16 d after harvesting increase significantly compared with those from flesh at 7 d after harvesting, and relative expression levels of NCED1, NCED2, ZEP1, and CCD2 genes of carotenoid degradation related genes also increase significantly, indicating that biosynthesis and degradation of carotenoid reach a balance, which lead to no significant variation of carotenoid content. The correlation analysis result shows that chlorophyll content in flesh of postharvest fruit of A. chinensis ‘Hort16A’ shows a significantly positive correlation with relative expression level of PAO2 gene at 0.05 level, but shows a significantly negative correlation with relative expression level of SGR1 gene at 0.05 level; carotenoid content shows significantly positive correlations with relative expression levels of LCYB2 and CYP1 genes at 0.05 level; correlations among relative expression levels of several biosynthesis and degradation related genes of chlorophyll and carotenoid are significant at 0.05 or 0.01 level. It is suggested that biosynthesis decrease of chlorophyll and its degradation increase in flesh of postharvest fruit of A. chinensis ‘Hort16A’ are the major causes which lead to decrease of chlorophyll content and yellow of flesh.
 

关键词中华猕猴桃品种‘Hort16A’; 果肉颜色; 叶绿素; 类胡萝卜素; 基因表达
Key wordsActinidia chinensis ‘Hort16A’; flesh color; chlorophyll; carotenoid; gene expression
作者张计育, 潘德林, 贾展慧, 王刚, 王涛, 翟敏, 郭忠仁
所在单位江苏省中国科学院植物研究所(南京中山植物园)
点击量217
基金项目江苏省自然科学基金资助项目(BK20171328)