CsMYB184 regulates caffeine biosynthesis in tea plants

• DOI: 10.1111/pbi.13814
• Publication Date: 2022-03-25T09:00:14Z
• Authors: Penghui Li; Zhili Ye; Jiamin Fu; Yujie Xu; Yihua Shen; Yanrui Zhang; Dingkun Tang; Ping Li; Hao Zuo; Wei Tong; Shucai Wang; Alisdair R. Fernie; Jian Zhao
• Keywords: 0301 basic medicine; 03 medical and health sciences; Tea; Caffeine; Brief Communications; Camellia sinensis

As the most well-known and globally consumed central nervous system stimulant, caffeine is a purine alkaloid natural product usually derived from tea coffee. Caffeine has wide range of health benefits on human body, plays crucial roles in pollination, resistance to herbivore attacks, pathogen infections plants (Zhao et al., 2020). While biosynthetic pathways have been extensively studied (Camellia sinensis L) coffee plants, regulation biosynthesis not understood Tea Synthase1 (TCS1) first N-methyltransferase gene reported plant, possessing 1-N methyltransferase activity responsible for converting theobromine (Kato 2000). Studies structure–activity TCS1 genetic variations plant populations supported that determination enzyme content (Jin 2016). To explore biosynthesis, 23 candidate transcription factors (TFs) Weighted Gene Co-expression Network Analysis were screened luciferase reporter activation driven by promoter (Figure S1). MYB184 (TEA029017) showed highest with 4.7-fold 1a). Yeast one-hybrid assay −828 −1670 bp region promoter, which contains an MYBCORE fused MYB1AT-MYBPLANT, was critically required recognition 1b). In planta trans-activation assays further confirmed regions binding activating be between −1596 1c). EMSA performed validate MYB1AT-MYBPLANT motif vitro 1d–f). We then examined function regulating synthesis plants. An antisense oligodeoxynucleotide (asODN) interference experiment shoot tips knock down expression (MYB184-KD) 1g). Accordingly, contents significantly reduced MYB184-KD compared senseODN control 1h–i). However, overexpression (MYB184OE) transgenic hairy root lines up-regulated thereby increased as wild-type controls 1j–m). KeKecha ptilophylla, KKC short), belonging Thea section, had lower but higher 1n). Although previous study NMT modern cultivars 2016), we detected level than other 1o). understand why down-regulated, cloned sequences SCZ. alignment did show critical Indels or SNPs MYB sites 1p). On hand, transcriptome analyses only ~14-fold 1q,r). thus proposed transcript might cause level. (proMYB184KKC), it those cultivars. A 437-bp long terminal repeat (LTR) insertion identified proMYB184KKC at site −982 bp, these promoters cultivars, verified both cloning detection PCR primers specific LTR 1s). leads suppression (Xia 2020), may explain Indeed, GUS exhibited clearly four representative without 1t). concluded resulted suppressed expression, leading KKC. expand Camellia species, several wild relatives are known contain levels 1u). They also containing (Figures 1v,w S2). This supports indispensable role C. sinensis. summary, characterized major activator production ptilophylla explained its low content. Our offer molecular tool breeding low-caffeine varieties meet market demands. The work National Natural Science Foundation China (32002089), Key Research Development Program (2018YFD1000601), Anhui Province (18030701155), funding Agricultural University State Laboratory Plant Biology Utilization. authors declare no conflict interest. J.Z. conceived research. P.H.L., J.M.F., Z.L.Y., Y.J.X., Y.H.S., Y.R.Z., D.K.T., P.L., H.Z, W.T. experiments J.Z., S.C.W., F.R.A. wrote manuscript. Figure S1 regulator screening S2 Specific pathway Please note: publisher functionality any supporting information supplied authors. Any queries (other missing content) should directed corresponding author article.