Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation, College of Life Science and Medicine, Zhejiang Sci-Tech University, Hangzhou, 310018, China.
Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, School of Life Sciences, Taizhou University, Taizhou, 318000, China.
BMC Genomics. 2024 Oct 13;25(1):952. doi: 10.1186/s12864-024-10882-2.
MYB transcription factors regulate anthocyanin biosynthesis across numerous plant species. However, comprehensive genome-wide investigations regarding the R2R3-MYB gene family and its involvement in regulating anthocyanin biosynthesis in the red and white fruit color morphs of Fragaria pentaphylla remain scarce.
A total of 101 FpR2R3-MYB genes were identified from the F. pentaphylla genome and were divided into 34 subgroups based on phylogenetic analysis. Gene structure (exon/intron) and protein motifs were particularly conserved among the FpR2R3-MYB genes, especially members within the same subgroup. The FpR2R3-MYB genes were distributed over seven F. pentaphylla chromosomes. Analysis of gene duplication events revealed five pairs of tandem duplication genes and 16 pairs of segmental duplication genes, suggesting that segmental duplications are the major pattern for expansion of the FpR2R3-MYB gene family expansion in F. pentaphylla. Cis-regulatory elements of the FpR2R3-MYB promoters were involved in cellular development, phytohormones, environmental stress and photoresponse. Based on the analysis of the FpR2R3-MYB gene family and transcriptome sequencing (RNA-seq) data, FpMYB9 was identified as a key transcription factor involved in the regulation of anthocyanin synthesis in F. pentaphylla fruits. The expression of FpMYB9 increases significantly during the ripening stage of red fruits, as confirmed by reverse transcription quantitative real-time PCR. In addition, subcellular localization experiments further confirmed the nuclear presence of FpMYB9, supporting its role as a transcription factor involved in anthocyanin biosynthesis.
Our results showed that the FpR2R3-MYB genes are highly conserved and play important roles in the anthocyanin biosynthesis in F. pentaphylla fruits. Our results also provide a compelling basis for further understanding of the regulatory mechanism underlying the role of FpMYB9 in anthocyanin formation in F. pentaphylla fruits.
MYB 转录因子调节着众多植物物种中花色苷生物合成。然而，关于 R2R3-MYB 基因家族及其在调控五叶草莓红、白果实颜色形态花色苷生物合成中的作用的全基因组范围的综合研究仍然很少。
从五叶草莓基因组中鉴定出 101 个 FpR2R3-MYB 基因，并根据系统发育分析将其分为 34 个亚组。FpR2R3-MYB 基因的基因结构（外显子/内含子）和蛋白基序特别保守，特别是同一亚组内的成员。FpR2R3-MYB 基因分布在七组五叶草莓染色体上。基因复制事件分析显示，有 5 对串联重复基因和 16 对片段重复基因，表明片段重复是 FpR2R3-MYB 基因家族在五叶草莓中扩张的主要模式。FpR2R3-MYB 启动子的顺式调控元件参与细胞发育、植物激素、环境胁迫和光响应。基于 FpR2R3-MYB 基因家族和转录组测序（RNA-seq）数据分析，鉴定出 FpMYB9 是参与五叶草莓果实花色苷合成调控的关键转录因子。通过反转录定量实时 PCR 证实，FpMYB9 在红果成熟阶段的表达显著增加。此外，亚细胞定位实验进一步证实了 FpMYB9 的核存在，支持其作为参与花色苷生物合成的转录因子的作用。
我们的研究结果表明，FpR2R3-MYB 基因高度保守，在五叶草莓果实花色苷生物合成中发挥重要作用。我们的研究结果还为进一步了解 FpMYB9 在五叶草莓果实花色苷形成中的作用的调控机制提供了有力依据。
