Liu Qingchun, Song Yi, Liu Yanfeng, Xu Xiao, Shao An, Wei Meng, He Yang, Zhang Xinpei, Wang Wei
School of Resources and Environmental Engineering, Ludong University, Yantai, China.
School of Horticulture, Ludong University, Yantai, China.
Ecotoxicol Environ Saf. 2025 Jul 28;302:118753. doi: 10.1016/j.ecoenv.2025.118753.
B-box (BBX) proteins, a subfamily of zinc-finger transcription factors, play a crucial role in regulating various physiological and developmental processes in plants, as well as in mediating stress responses. However, comprehensive characterization of the BBX gene family in perennial ryegrass has not been performed, and their potential functions in response to abiotic stress remain unclear. In the present study, we systematically identified 26 BBX genes in the perennial ryegrass genome and classified them into five distinct groups based on their phylogenetic relationships. These classifications were further supported by their gene structures and conserved protein motifs. Collinearity analysis revealed that segmental duplication events have been a primary driver for the expansion of the LpBBX family, with duplicated genes exhibiting strong signatures of purifying selection throughout evolution. Numerous cis-regulatory elements associated with hormonal signaling and abiotic stress response were identified in the promoter regions of LpBBXs. Transcription factor regulatory network analysis predicted several key families, including ERF, MYB, and NAC, as potential upstream regulators of LpBBX genes. Transcriptome analysis showed that LpBBXs exhibited diverse expression patterns in different tissues and responded positively to drought stress. Finally, functional analysis revealed that LpBBX3 possessed transcriptional activation activity and was localized in the nucleus. Heterologous expression of LpBBX3 significantly improved both drought and salt tolerance of yeast cells. These findings provide valuable genetic resources and insight into the LpBBX family, laying a crucial foundation for elucidating their biological functions in abiotic stress adaptation mechanisms in perennial ryegrass.
B-box（BBX）蛋白是锌指转录因子的一个亚家族，在调节植物的各种生理和发育过程以及介导应激反应中起着关键作用。然而，多年生黑麦草中BBX基因家族的全面表征尚未进行，其在应对非生物胁迫中的潜在功能仍不清楚。在本研究中，我们在多年生黑麦草基因组中系统地鉴定出26个BBX基因，并根据它们的系统发育关系将它们分为五个不同的组。这些分类进一步得到它们的基因结构和保守蛋白基序的支持。共线性分析表明，片段重复事件是LpBBX家族扩张的主要驱动力，在整个进化过程中，重复基因表现出强烈的纯化选择特征。在LpBBXs的启动子区域鉴定出许多与激素信号传导和非生物胁迫反应相关的顺式调控元件。转录因子调控网络分析预测了几个关键家族，包括ERF、MYB和NAC，作为LpBBX基因的潜在上游调控因子。转录组分析表明，LpBBXs在不同组织中表现出不同的表达模式，并对干旱胁迫有积极响应。最后，功能分析表明，LpBBX3具有转录激活活性，定位于细胞核。LpBBX3的异源表达显著提高了酵母细胞的耐旱性和耐盐性。这些发现为LpBBX家族提供了有价值的遗传资源和见解，为阐明它们在多年生黑麦草非生物胁迫适应机制中的生物学功能奠定了关键基础。
