Table_2_Identification of QTL controlling volatile terpene contents in tea plant (Camellia sinensis) using a high-aroma ‘Huangdan’ x ‘Jinxuan’ F1 population.xlsx

Aroma is an important factor affecting the character and quality of tea. The improvement of aroma trait is a crucial research direction of tea plant breeding. Volatile terpenes, as the major contributors to the floral odors of tea products, also play critical roles in the defense responses of plants to multiple stresses. However, previous studies have largely focused on the aroma formation during the manufacture of tea or the comparison of raw tea samples. The mechanisms causing different aroma profiles between tea cultivars have remained underexplored. In the current study, a high-density genetic linkage map of tea plant was constructed based on an F1 population of ‘Huangdan’ × ‘Jinxuan’ using genotyping by sequencing. This linkage map covered 1754.57 cM and contained 15 linkage groups with a low inter-marker distance of 0.47 cM. A total of 42 QTLs associated with eight monoterpene contents and 12 QTLs associated with four sesquiterpenes contents were identified with the average PVE of 12.6% and 11.7% respectively. Furthermore, six candidate genes related to volatile terpene contents were found in QTL cluster on chromosome 5 by RNA-seq analysis. This work will enrich our understanding of the molecular mechanism of volatile terpene biosynthesis and provide a theoretical basis for tea plant breeding programs for aroma quality improvement.

香气是影响茶叶品质与特性的重要因素。提升香气特性是茶树育种研究中的关键方向。挥发性萜烯类物质，作为茶叶产品花香的主要贡献者，亦在植物对多种胁迫的防御反应中扮演着至关重要的角色。然而，过往研究主要集中于茶叶制造过程中的香气形成或原生茶样的比较。导致不同茶树品种间香气谱差异的机制尚未得到充分探究。在本研究中，基于‘黄丹’ב金萱’的F1群体，利用测序分型技术构建了茶树的高密度遗传连锁图谱。此连锁图谱覆盖了1754.57 cM，包含15个连锁群，标记间距离低至0.47 cM。通过关联分析，共鉴定出与八种单萜含量相关的42个QTL和与四种倍半萜含量相关的12个QTL，其平均PVE分别为12.6%和11.7%。此外，通过RNA-seq分析，在染色体5的QTL簇中发现了与挥发性萜烯含量相关的六个候选基因。本研究将丰富我们对挥发性萜烯生物合成分子机制的理解，并为提升茶叶香气品质的育种计划提供理论依据。