Zou Lina, Wang Linna, He Jinhua, Yao Zixian, Zhang Shunran, Xiang Yan
Anhui Provincial Key Laboratory of Forest Resources and Silviculture, Anhui Agricultural University, Hefei 2300119, China.
Anhui Provincial Key Laboratory of Forest Resources and Silviculture, Anhui Agricultural University, Hefei 2300119, China.
Plant Sci. 2025 Jul 11;359:112662. doi: 10.1016/j.plantsci.2025.112662.
The basic helix-loop-helix (bHLH) gene family plays vital roles across various plant species. However, the bHLH family has not been reported in pean (Carya illinoinensis). In this study, 164 CibHLHs were identified, exhibiting high evolutionary conservation as revealed by gene structure, conserved motifs, domains, and collinearity analyses. Promoter analysis revealed that many CibHLHs contain cis-acting elements related to abiotic stress responses. CibHLH141 and CibHLH127 were significantly upregulated in both leaves and roots of pecan under iron deficiency. The subcellular localization investigation confirmed that CibHLH141 and CibHLH127 are nuclear localization proteins. Transcriptional activity assays demonstrated that both possess transcriptional activity, with the active region located at the N-terminus. Transient overexpression in tobacco and stable overexpression in Arabidopsis confirmed their positive roles in enhancing tolerance to iron deficiency. Furthermore, in vivo and in vitro assays revealed stable interactions between CibHLH141, CibHLH127 and CibHLH119, with CibHLH119 also implicated in the iron regulatory network. Overall, these findings advance our understanding of the CibHLH gene family and lay a foundation for elucidating the molecular mechanisms of iron homeostasis in pecan. Moreover, this study offers theoretical support for breeding stress-resilient pecan cultivars, enhancing their ecological and economic value.
基本螺旋-环-螺旋（bHLH）基因家族在各种植物物种中发挥着至关重要的作用。然而，山核桃（Carya illinoinensis）中尚未报道过bHLH家族。在本研究中，共鉴定出164个CibHLH基因，通过基因结构、保守基序、结构域和共线性分析表明它们具有高度的进化保守性。启动子分析显示，许多CibHLH基因含有与非生物胁迫响应相关的顺式作用元件。缺铁条件下，山核桃叶片和根系中的CibHLH141和CibHLH127均显著上调。亚细胞定位研究证实，CibHLH141和CibHLH127是核定位蛋白。转录活性分析表明，二者均具有转录活性，且活性区域位于N端。在烟草中的瞬时过表达和在拟南芥中的稳定过表达证实了它们在增强缺铁耐受性方面的积极作用。此外，体内和体外实验揭示了CibHLH141、CibHLH127和CibHLH119之间存在稳定的相互作用，CibHLH119也参与了铁调节网络。总体而言，这些发现增进了我们对CibHLH基因家族的理解，为阐明山核桃中铁稳态的分子机制奠定了基础。此外，本研究为培育抗逆性山核桃品种提供了理论支持，提高了其生态和经济价值。
