红肉菠萝蜜果实中“紫黄质”代谢关键基因分离鉴定

Jackfruit (Artocarpus heterophyllus Lam.) is a typical tropic fruit. The carotenoids composition in flesh is an important component of quality traits, determining the color and nutrition of fruit, making the “Red-flesh” become a new focus in Jackfruit breeding and consumption. However, the red pigment and its biosynthetic mechanism were poorly understood. Our previous study indicated that the total carotenoid content as well as the main components in Red-flesh Jackfruit were superior to that of Yellow-flesh. The products of violaxanthin cleavage dioxygenization (β-citraurin) and derivatization (luteoxanthin) were specific pigments in Red-flesh, accounting for over 80% of the total content. In this project, based on the difference in violaxanthin-metabolism, we will evaluate the transcriptome changes between Red-flesh ‘Sijihong’ and Yellow-flesh ‘Qiongyin 1’ using comparative transcriptome analysis. The genes involved in pigment accumulation in flesh of Red-flesh Jackfruit will be isolated by comparing the expression patterns of carotenoid metabolism related genes, analyzing the relationship of transcripts with the accumulation of differential pigments during perianth development. To further characterize the role of the pigmentation-related genes, enzyme functional analyses and gene structural alignment will be performed. The results of this research will enrich the theory of carotenoid mechanism, laying the foundation for quality breeding in Jackfruit.

菠萝蜜是典型的热带水果，类胡萝卜素是其果实品质构成的重要因子，影响果肉的色泽和营养特性，红肉菠萝蜜是当前市场需求和育种研究的新焦点。前期研究发现，红肉品种类胡萝卜素总体含量及种类高于黄肉品种，紫黄质前体裂解产物及其下游衍生化产物为红色果肉中特有呈色组分，占类胡萝卜素总量的80%以上。为进一步鉴定红肉呈色关键基因，本项目基于“紫黄质”代谢差异，以菠萝蜜红肉品种‘四季红’为研究材料，黄肉品种‘琼引1号’为对照，开展不同色泽果肉的比较转录组学研究，根据类胡萝卜素代谢相关基因在不同材料间的表达差异，以及这些差异与呈色组分积累模式之间的关系，初步筛选类胡萝卜素代谢候选关键基因。在此基础上，通过关键基因的功能分析及不同材料间基因结构比对，鉴定红肉呈色基因。研究结果将丰富植物类胡萝卜素代谢理论，对菠萝蜜品质改良的育种研究有理论和实践意义。