Identification and expression profiling of MYB transcription factors related to l-theanine biosynthesis in Camellia sinensis

Abstract Background Sugarcane (Saccharum) is the most critical sugar crop worldwide. As one of the most enriched transcription factor families in plants, MYB genes display a great potential to contribute to sugarcane improvement by trait modification. We have identified the sugarcane MYB gene family at a whole-genome level through systematic evolution analyses and expression profiling. R2R3-MYB is a large subfamily involved in many plant-specific processes. Results A total of 202 R2R3-MYB genes (356 alleles) were identified in the polyploid Saccharum spontaneum genomic sequence and classified into 15 subgroups by phylogenetic analysis. The sugarcane MYB family had more members by a comparative analysis in sorghum and significant advantages among most plants, especially grasses. Collinearity analysis revealed that 70% of the SsR2R3-MYB genes had experienced duplication events, logically suggesting the contributors to the MYB gene family expansion. Functional characterization was performed to identify 56 SsR2R3-MYB genes involved in various plant bioprocesses with expression profiling analysis on 60 RNA-seq databases. We identified 22 MYB genes specifically expressed in the stem, of which RT-qPCR validated MYB43, MYB53, MYB65, MYB78, and MYB99. Allelic expression dominance analysis implied the differential expression of alleles might be responsible for the high expression of MYB in the stem. MYB169, MYB181, MYB192 were identified as candidate C4 photosynthetic regulators by C4 expression pattern and robust circadian oscillations. Furthermore, stress expression analysis showed that MYB36, MYB48, MYB54, MYB61 actively responded to drought treatment; 19 and 10 MYB genes were involved in response to the sugarcane pokkah boeng and mosaic disease, respectively. Conclusions This is the first report on genome-wide analysis of the MYB gene family in sugarcane. SsMYBs probably played an essential role in stem development and the adaptation of various stress conditions. The results will provide detailed insights and rich resources to understand the functional diversity of MYB transcription factors and facilitate the breeding of essential traits in sugarcane.

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MYB Transcription Factors in Chinese Pear (Pyrus bretschneideri Rehd.): Genome-Wide Identification, Classification, and Expression Profiling during Fruit Development

Frontiers in Plant Science ◽

10.3389/fpls.2016.00577 ◽

2016 ◽

Vol 7 ◽

Cited By ~ 40

Author(s):

Yunpeng Cao ◽

Yahui Han ◽

Dahui Li ◽

Yi Lin ◽

Yongping Cai

Keyword(s):

Transcription Factors ◽

Fruit Development ◽

Expression Profiling ◽

Myb Transcription Factors ◽

Genome Wide

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Systematic analysis of the R2R3-MYB family of transcription factors in Camellia sinensis: evidence for species-specific catechin biosynthesis regulation

10.1101/2021.07.21.453189 ◽

2021 ◽

Author(s):

Jingyi Li ◽

Shaoqun Liu ◽

Peifen Chen ◽

Jiarong Cai ◽

Song Tang ◽

...

Keyword(s):

Transcriptional Regulation ◽

Transcription Factors ◽

Camellia Sinensis ◽

Myb Transcription Factor ◽

Myb Transcription Factors ◽

Evolutionary Diversification ◽

Health Promoting ◽

Myb Genes ◽

Species Specific ◽

R2r3 Myb

Tea from Camellia sinensis is one of the most popular beverages worldwide, lauded for its charming flavors and health-promoting properties. C. sinensis produces an abundance of specialized metabolites, which makes it an excellent model for digging into the genetic regulation of plant-specific metabolite biosynthesis. The most abundant health-promoting metabolites in tea are galloylated catechins, and the most bioactive of the galloylated catechins, epigallocatechin gallate (EGCG), is exclusively found in C. sinensis. The R2R3-MYB transcription factor family regulates metabolism of phenylpropanoids, the precursors to catechins, in various plant lineages. However, the transcriptional regulation of galloylated catechin biosynthesis remains elusive. Species-expanded or specific MYB transcription factors may regulate species-specific metabolite biosynthesis. This study mined the R2R3-MYB transcription factors associated with galloylated catechin biosynthesis in C. sinensis. A total of 118 R2R3-MYB proteins, classified into 38 subgroups, were identified. R2R3-MYB subgroups specific to or expanded in C. sinensis were hypothesized to be essential to evolutionary diversification of tea-specific metabolites. Notably, nine of these R2R3-MYB genes were expressed preferentially in apical buds and young leaves, exactly where galloylated catechins accumulate. Three putative R2R3-MYB genes displayed strong correlation with key galloylated catechin biosynthesis genes, suggesting a role in regulating biosynthesis of epicatechin gallate (ECG) and EGCG. Overall, this study paves the way to reveal the transcriptional regulation of galloylated catechins in C. sinensis.

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