Yu Junpeng, Wu Ze, Liu Xinyue, Fang Qianqian, Pan Xue, Xu Sujuan, He Man, Lin Jinxing, Teng Nianjun
Key Laboratory of Landscaping, Ministry of Agriculture and Rural Affairs, Key Laboratory of Biology of Ornamental Plants in East China, National Forestry and Grassland Administration, College of Horticulture, Nanjing Agricultural University, No. 1, Weigang, Xuanwu District, Nanjing 210095, China.
Lily Science and Technology Backyard Qixia of Jiangsu/Jiangsu Graduate Workstation, Waisha Village, Baguazhou Street, Qixia District, Nanjing 210043, China.
Hortic Res. 2024 Dec 4;12(3):uhae339. doi: 10.1093/hr/uhae339. eCollection 2025 Mar.
The homeostasis of gibberellin (GA) is crucial for the normal development of anthers, but its underlying regulatory mechanisms are not clear. The GA-induced v-Myb myeloblastosis viral oncogene homolog (MYB) transcription factor LoMYB65 is involved in anther development. In this study, we screened and identified an interacting protein of LoMYB65, Oriental Hybrids BEL1-Like Homeodomain6 (LoBLH6). LoBLH6 was localized in both the nucleus and cytoplasm, and it interacted with LoMYB65 through its BELL domain, exhibiting transcriptional repression activity. was continuously expressed during anther development, with particularly high expression in the mid and late stages. hybridization revealed high expression of in the tapetum and microspores, with the same tissue specificity as . Silencing of in lilies resulted in abnormal anther development, reduced pollen, and increased GA content. The application of GA-induced phenotypes in the anthers and pollen of lily that were similar to the silencing of . Further research showed that LoBLH6 directly binds to the promoter of Oriental Hybrids () to suppress its expression, and coexpression with LoMYB65 enhances this repression. Additionally, GA treatment enhanced the interaction between LoBLH6 and LoMYB65 and their complex's inhibitory effect on downstream target genes. During the transition from microspores to mature pollen grains in lily anthers, GA levels maintain a steady state, which is disrupted by silencing , leading to abnormal pollen development. Overall, our results reveal that the interaction between LoBLH6 and LoMYB65 regulates anther development through feedback regulation of GA synthesis.
赤霉素（GA）的稳态对于花药的正常发育至关重要，但其潜在的调控机制尚不清楚。GA诱导的v-Myb髓细胞白血病病毒癌基因同源物（MYB）转录因子LoMYB65参与花药发育。在本研究中，我们筛选并鉴定了LoMYB65的一个相互作用蛋白，东方百合BEL1样同源结构域6（LoBLH6）。LoBLH6定位于细胞核和细胞质中，它通过其BELL结构域与LoMYB65相互作用，表现出转录抑制活性。在花药发育过程中持续表达，在中后期表达量特别高。原位杂交显示在绒毡层和小孢子中高表达，与具有相同的组织特异性。百合中LoBLH6的沉默导致花药发育异常、花粉减少和GA含量增加。GA的施用在百合的花药和花粉中诱导出与LoBLH6沉默相似的表型。进一步研究表明，LoBLH6直接结合东方百合GA20氧化酶（LoGA20ox）的启动子以抑制其表达，与LoMYB65共表达增强这种抑制作用。此外，GA处理增强了LoBLH6与LoMYB65之间的相互作用以及它们的复合物对下游靶基因的抑制作用。在百合花药从小孢子向成熟花粉粒转变过程中，GA水平保持稳定状态，而LoBLH6沉默会破坏这种状态，导致花粉发育异常。总体而言，我们的结果表明，LoBLH6与LoMYB65之间的相互作用通过对GA合成的反馈调节来调控花药发育。
