Department of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, P.O. Box No. 6, Palampur, HP, 176061, India.
Academy of Scientific and Innovative Research (AcSIR), CSIR-HRDC Campus, Ghaziabad, Uttar Pradesh, 201 002, India.
Sci Rep. 2021 Jan 13;11(1):1244. doi: 10.1038/s41598-020-80437-4.
Purple-tea, an anthocyanin rich cultivar has recently gained popularity due to its health benefits and captivating leaf appearance. However, the sustainability of purple pigmentation and anthocyanin content during production period is hampered by seasonal variation. To understand seasonal dependent anthocyanin pigmentation in purple tea, global transcriptional and anthocyanin profiling was carried out in tea shoots with two leaves and a bud harvested during in early (reddish purple: S1_RP), main (dark gray purple: S2_GP) and backend flush (moderately olive green: S3_G) seasons. Of the three seasons, maximum accumulation of total anthocyanin content was recorded in S2_GP, while least amount was recorded during S3_G. Reference based transcriptome assembly of 412 million quality reads resulted into 71,349 non-redundant transcripts with 6081 significant differentially expressed genes. Interestingly, key DEGs involved in anthocyanin biosynthesis [PAL, 4CL, F3H, DFR and UGT/UFGT], vacuolar trafficking [ABC, MATE and GST] transcriptional regulation [MYB, NAC, bHLH, WRKY and HMG] and Abscisic acid signaling pathway [PYL and PP2C] were significantly upregulated in S2_GP. Conversely, DEGs associated with anthocyanin degradation [Prx and lac], repressor TFs and key components of auxin and ethylene signaling pathways [ARF, AUX/IAA/SAUR, ETR, ERF, EBF1/2] exhibited significant upregulation in S3_G, correlating positively with reduced anthocyanin content and purple coloration. The present study for the first-time elucidated genome-wide transcriptional insights and hypothesized the involvement of anthocyanin biosynthesis activators/repressor and anthocyanin degrading genes via peroxidases and laccases during seasonal induced leaf color transition in purple tea. Futuristically, key candidate gene(s) identified here can be used for genetic engineering and molecular breeding of seasonal independent anthocyanin-rich tea cultivars.
紫茶是一种富含花青素的品种，因其具有健康益处和迷人的叶片外观而受到广泛关注。然而，在生产过程中，紫色素和花青素含量的可持续性受到季节性变化的影响。为了了解紫茶季节性依赖的花青素着色，在早期（红紫色：S1_RP）、主季（深灰色紫色：S2_GP）和后季（中等橄榄绿色：S3_G）收获的有两片叶子和一个芽的茶芽中进行了全球转录组和花青素分析。在这三个季节中，S2_GP 中总花青素含量的积累最大，而 S3_G 中积累最少。基于参考的 4.12 亿个质量读数的转录组组装产生了 71349 个非冗余转录本，其中 6081 个基因有显著差异表达。有趣的是，参与花青素生物合成的关键 DEGs [PAL、4CL、F3H、DFR 和 UGT/UFGT]、液泡运输 [ABC、MATE 和 GST]、转录调控 [MYB、NAC、bHLH、WRKY 和 HMG] 和脱落酸信号通路 [PYL 和 PP2C] 在 S2_GP 中显著上调。相反，与花青素降解相关的 DEGs [Prx 和 lac]、抑制性 TF 和生长素和乙烯信号通路的关键成分 [ARF、AUX/IAA/SAUR、ETR、ERF、EBF1/2] 在 S3_G 中显著上调，与花青素含量和紫色着色减少呈正相关。本研究首次阐明了全基因组转录组学的见解，并假设在紫茶季节性诱导的叶片颜色转变过程中，花青素生物合成激活剂/抑制剂和花青素降解基因通过过氧化物酶和漆酶参与。从长远来看，这里鉴定的关键候选基因可以用于遗传工程和具有季节性的富含花青素的茶树品种的分子育种。
