Phylogenomic Analysis of R2R3 MYB Transcription Factors in Sorghum and their Role in Conditioning Biofuel Syndrome

Background : Large scale cultivation of sorghum for food, feed, and biofuel requires concerted efforts for engineering multipurpose cultivars with optimised agronomic traits. Due to their vital role in regulating the biosynthesis of phenylpropanoid-derived compounds, biomass composition, biotic, and abiotic stress response, R2R3-MYB family transcription factors are ideal targets for improving environmental resilience and economic value of sorghum. Methods: We used diverse computational biology tools to survey the sorghum genome to identify R2R3-MYB transcription factors followed by their structural and phylogenomic analysis. We used inhouse generated as well as publicly available high throughput expression data to analyse the R2R3 expression patterns in various sorghum tissue types. Results: We have identified a total of 134 R2R3-MYB genes from sorghum and developed a framework to predict gene functions. Collating information from the physical location, duplication, structural analysis, orthologous sequences, phylogeny, and expression patterns revealed the role of duplications in clade-wise expansion of the R2R3-MYB family as well as intra-clade functional diversification. Using publicly available and in-house generated RNA sequencing data, we provide MYB candidates for conditioning biofuel syndrome by engineering phenylpropanoid biosynthesis and sugar signalling pathways in sorghum. Conclusion: The results presented here are pivotal to prioritize MYB genes for functional validation and optimize agronomic traits in sorghum.

Download Full-text

Origins and Stepwise Expansion of R2R3-MYB Transcription Factors for the Terrestrial Adaptation of Plants

Frontiers in Plant Science ◽

10.3389/fpls.2020.575360 ◽

2020 ◽

Vol 11 ◽

Author(s):

Xiaojun Chang ◽

Shupeng Xie ◽

Lanlan Wei ◽

Zhaolian Lu ◽

Zhong-Hua Chen ◽

...

Keyword(s):

Transcription Factors ◽

Land Plants ◽

Monophyletic Group ◽

Myb Transcription Factors ◽

Genes Encoding ◽

Terrestrial Environments ◽

Myb Genes ◽

Myb Proteins ◽

R2r3 Myb ◽

R2r3 Myb Transcription Factors

The R2R3-MYB transcription factors play critical roles in various processes in embryophytes (land plants). Here, we identified genes encoding R2R3-MYB proteins from rhodophytes, glaucophytes, Chromista, chlorophytes, charophytes, and embryophytes. We classified the R2R3-MYB genes into three subgroups (I, II, and III) based on their evolutionary history and gene structure. The subgroup I is the most ancient group that includes members from all plant lineages. The subgroup II was formed before the divergence of charophytes and embryophytes. The subgroup III genes form a monophyletic group and only comprise members from land plants with conserved exon–intron structure. Each subgroup was further divided into multiple clades. The subgroup I can be divided into I-A, I-B, I-C, and I-D. The I-A, I-B, and I-C are the most basal clades that have originated before the divergence of Archaeplastida. The I-D with the II and III subgroups form a monophyletic group, containing only green plants. The II and III subgroups form another monophyletic group with Streptophyta only. Once on land, the subgroup III genes have experienced two rounds of major expansions. The first round occurred before the origin of land plants, and the second round occurred after the divergence of land plants. Due to significant gene expansion, the subgroup III genes have become the predominant group of R2R3-MYBs in land plants. The highly unbalanced pattern of birth and death evolution of R2R3-MYB genes indicates their important roles in the successful adaptation and massive radiation of land plants to occupy a multitude of terrestrial environments.

Download Full-text

Expression pattern analysis of three R2R3-MYB transcription factors for the production of anthocyanin in different vegetative stages of Arabidopsis leaves

Applied Biological Chemistry ◽

10.1186/s13765-020-00584-0 ◽

2021 ◽

Vol 64 (1) ◽

Author(s):

Yeonjong Koo ◽

R. Scott Poethig

Keyword(s):

Transcription Factors ◽

Developmental Stages ◽

Myb Transcription Factors ◽

Expression Pattern Analysis ◽

Myb Genes ◽

R2r3 Myb ◽

Post Transcriptional Regulation ◽

Anthocyanin Production ◽

R2r3 Myb Transcription Factors

AbstractAnthocyanin is a type of flavonoid that appears purple in plants. PAP1, PAP2, and MYB113 are the three major R2R3-MYB transcription factors that regulate flavonoid biosynthesis in Arabidopsis thaliana. In this study, we found that the three MYB genes regulate anthocyanin accumulation in different leaf stages. Under limited nutrient conditions, PAP1 and PAP2 genes were highly induced in juvenile leaves. Conversely, MYB113 was expressed mainly in adult leaves. In addition, we investigated the role of trans-acting siRNA4 (TAS4) in the post-transcriptional regulation of anthocyanin expression in Arabidopsis leaves. In plant growth, the inhibition of PAP1 and PAP2 gene expression by TAS4 was observed only in juvenile leaves, and MYB113 inhibition was observed in adult leaves. In conclusion, we found that transcription and transcript repression of the three MYB genes is differentially regulated by TAS4 in leaf developmental stages. Our results improve the understanding of the regulation of plant anthocyanin production under stress conditions.

Download Full-text