Department of Agricultural Biotechnology, National Institute of Agricultural Sciences (NAS), RDA, Jeonju 54874, Korea.
Int J Mol Sci. 2022 Aug 4;23(15):8695. doi: 10.3390/ijms23158695.
Photosensory proteins known as photoreceptors (PHRs) are crucial for delineating light environments in synchronization with other environmental cues and regulating their physiological variables in plants. However, this has not been well studied in the Brassica genus, which includes several important agricultural and horticultural crops. Herein, we identified five major PHR gene families-phytochrome (PHY), cryptochrome (CRY), phototropin (PHOT), F-box containing flavin binding proteins (ZTL/FKF1/LKP2), and UV RESISTANCE LOCUS 8 (UVR8)-genomic scales and classified them into subfamilies based on their phylogenetic clustering with Arabidopsis homologues. The molecular evolution characteristics of Brassica PHR members indicated indirect expansion and lost one to six gene copies at subfamily levels. The segmental duplication was possibly the driving force of the evolution and amplification of Brassica PHRs. Gene replication retention and gene loss events of CRY, PHY, and PHOT members found in diploid progenitors were highly conserved in their tetraploid hybrids. However, hybridization events were attributed to quantitative changes in UVR8 and ZTL/FKF1/LKP2 members. All PHR members underwent purifying selection. In addition, the transcript expression profiles of PHR genes in different tissue and in response to exogenous ABA, and abiotic stress conditions suggested their multiple biological significance. This study is helpful in understanding the molecular evolution characteristics of Brassica PHRs and lays the foundation for their functional characterization.
光感受器（PHR）是一类感光蛋白，对于植物与其他环境信号同步感知光环境并调节其生理变量至关重要。然而，在包括几种重要农业和园艺作物的芸薹属中，这方面的研究还不够深入。本研究在基因组尺度上鉴定了 5 个主要的 PHR 基因家族（phytochrome，PHY；cryptochrome，CRY；phototropin，PHOT；F-box 富含黄素结合蛋白，ZTL/FKF1/LKP2；和 UV RESISTANCE LOCUS 8，UVR8），并根据与拟南芥同源物的系统发育聚类将它们分为亚家族。芸薹属 PHR 成员的分子进化特征表明，在亚家族水平上发生了间接扩张和 1 到 6 个基因拷贝的丢失。片段重复可能是芸薹属 PHR 进化和扩增的驱动力。在其同源四倍体杂种中，二倍体祖先中发现的 CRY、PHY 和 PHOT 成员的基因复制保留和基因丢失事件高度保守。然而，杂交事件归因于 UVR8 和 ZTL/FKF1/LKP2 成员的数量变化。所有 PHR 成员都经历了纯化选择。此外，PHR 基因在不同组织中的转录表达谱以及对外源 ABA 和非生物胁迫条件的响应表明了它们的多种生物学意义。本研究有助于理解芸薹属 PHR 的分子进化特征，并为其功能表征奠定了基础。
