Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education & National Engineering Laboratory for Breeding of Endangered Medicinal Materials, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Hainan Provincial Key Laboratory of Resources Conservation and Development of Southern Medicine & Key Laboratory of State Administration of Traditional Chinese Medicine for Agarwood Sustainable Utilization, Hainan Branch of the Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Haikou, China.
PLoS One. 2023 Nov 16;18(11):e0294358. doi: 10.1371/journal.pone.0294358. eCollection 2023.
The endangered tree species of the Aquilaria genus produce agarwood, a high value material produced only after wounding; however, conservation of Aquilaria seeds is difficult. The B3 transcription factor family has diverse important functions in plant development, especially in seed development, although their functions in other areas, such as stress responses, remain to be revealed. Here germination tests proved that the seeds of A. sinensis were recalcitrant seeds. To provide insights into the B3 superfamily, the members were identified and characterized by bioinformatic approaches and classified by phylogenetic analysis and domain structure. In total, 71 members were identified and classified into four subfamilies. Each subfamily not only had similar domains, but also had conserved motifs in their B3 domains. For the seed-related LAV subfamily, the B3 domain of AsLAV3 was identical to that of AsVALs but lacked a typical zf-CW domain such as VALs. AsLAV5 lacks a typical PHD-L domain present in Arabidopsis VALs. qRT-PCR expression analysis showed that the LEC2 ortholog AsLAV4 was not expressed in seeds. RAVs and REMs induced after wound treatment were also identified. These findings provide insights into the functions of B3 genes and seed recalcitrance of A. sinensis and indicate the role of B3 genes in wound response and agarwood formation.This is the first work to investigate the B3 family in A. sinensis and to provide insights of the molecular mechanism of seed recalcitrance.This will be a valuable guidance for studies of B3 genes in stress responses, secondary metabolite biosynthesis, and seed development.
沉香属濒危树种产生沉香，这是一种只有在受伤后才会产生的高价值物质；然而，沉香种子的保存却很困难。B3 转录因子家族在植物发育中具有多种重要功能，特别是在种子发育中，尽管它们在其他领域的功能，如应激反应，仍有待揭示。这里的萌发试验证明，白木香种子是顽拗型种子。为了深入了解 B3 超家族，我们采用生物信息学方法鉴定和特征化了该家族的成员，并通过系统发生分析和结构域分类进行了分类。总共鉴定出 71 个成员，并分为四个亚家族。每个亚家族不仅具有相似的结构域，而且在 B3 结构域中也具有保守的基序。对于与种子相关的 LAV 亚家族，AsLAV3 的 B3 结构域与 AsVALs 相同，但缺乏 VALs 典型的 zf-CW 结构域。AsLAV5 缺乏拟南芥 VALs 中存在的典型 PHD-L 结构域。qRT-PCR 表达分析表明，LEC2 同源物 AsLAV4 在种子中不表达。还鉴定了创伤处理后诱导的 RAVs 和 REMs。这些发现为 B3 基因的功能和白木香种子的顽拗性提供了深入的了解，并表明 B3 基因在创伤反应和沉香形成中的作用。这是首次对白木香中 B3 家族进行研究，并为研究种子顽拗性的分子机制提供了线索。这将为 B3 基因在应激反应、次生代谢物生物合成和种子发育中的研究提供有价值的指导。
