Abstract

Main conclusion  A normal tea plant with one albino branch was discovered. RNA sequencing, albinism phenotype and ultrastructural observations provided a valuable understanding of the albino mechanism in tea plants.

Tea plants with a specific color (white or yellow) have been studied extensively. A normal tea plant (Camellia sinensis cv. quntizhong) with one albino branch was discovered in a local tea plantation in Huangshan, Anhui, China. The pure albino leaves on this special branch had accumulated a fairly high content of amino acids, especially theanine (45.31 mg/g DW), and had a low concentration of polyphenols and an extremely low chlorophyll (Chl) content compared with control leaves. Ultrastructural observation of an albino leaf revealed no chloroplasts, whereas it was viable in the control leaf. RNA sequencing and differentially expressed gene (DEG) analysis were performed on the albino leaves and on control leaves from a normal green branch. The related genes involved in theanine and polyphenol biosynthesis were also investigated in this study. DEG expression patterns in Chl biosynthesis or degradation, carotenoid biosynthesis or degradation, chloroplast development, and biosynthesis were influenced in the albino leaves. Chloroplast deletion in albino leaves had probably destroyed the balance of carbon and nitrogen metabolism, leading to a high accumulation of free amino acids and a low concentration of polyphenols in the albino leaves. The obtained results can provide insight into the mechanism underlying this special albino branch phenotype, and are a valuable contribution toward understanding the albino mechanism in tea plants.

 后记

       又一个白化特异资源的研究。含有特异性状的材料不仅在育种应用方面具有潜在的利用价值，同样也是进行基础研究的好材料。对于茶树来说，白化（黄化）的材料一般都具有较高的氨基酸含量，这对于培育高茶氨酸茶树品种价值巨大，从“黄金芽”、“安吉白茶”等品种的市场欢迎度就可见一斑。然而对于它们的白化机制仍然不清楚，虽然以“黄金芽”、“安吉白茶”等为材料进行了大量研究，包括转录组、蛋白组、代谢组以及翻译后修饰等，但是因为缺乏统一的参考基因组，这些不同的研究很难整合到一块，所以大部分的研究都变成了“烂尾楼”——发完文章就完事。如今两大类栽培种茶树的基因组都已公布，虽然质量并不是很高，但是毕竟有了统一的参考，不至于再出现你有你的命名，我有我的命名，这次有这次的命名，下次又是另一个命名。能不能把前期的数据重新比对参考基因组重新分析呢？这样会不会有新的发现？（不成熟的一点想法）

相关阅读：

转录组与代谢组分析洞察“黄金芽”氨基酸代谢

茶树品种“黄金芽”叶片颜色与黄酮类和类胡萝卜素合成基因表达的分子联系

安吉白茶“变色”之谜

安吉白茶周期性白化阶段光合作用和次生代谢物合成途径的乙酰化蛋白质组学研究

转录组揭示“白鸡冠”茶树叶片光照响应调控网络