Jiangxi Key Laboratory for Postharvest Technology and Nondestructive Testing of Fruits & Vegetables, Collaborative Innovation Center of Post-Harvest Key Technology and Quality Safety of Fruits and Vegetables, Jiangxi Agricultural University, Nanchang 330045, China; Key Laboratory of Crop Physiology, Ecology, and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China.
Jiangxi Key Laboratory for Postharvest Technology and Nondestructive Testing of Fruits & Vegetables, Collaborative Innovation Center of Post-Harvest Key Technology and Quality Safety of Fruits and Vegetables, Jiangxi Agricultural University, Nanchang 330045, China.
Int J Biol Macromol. 2023 May 15;237:124071. doi: 10.1016/j.ijbiomac.2023.124071. Epub 2023 Mar 21.
The B-box (BBX) transcription factors are widely implicated in plant growth, development, and response to various biotic and abiotic stresses. However, their roles in the response of pepper to Phytophthora capsici infection (PCI) remain largely unexplored. Here, we report a total of 25 CaBBX genes with an uneven distribution were identified in pepper genome, and their characteristics, phylogenetic relationships, gene structures, conserved domains, and expression profiles were validated. CaBBXs were classified into five major clades (I to V) based on their phylogenetic relationships and conserved domains (presence of one or two B-box domains and a CCT domain). Gene duplication analysis demonstrated that there are two segmental duplication events but no tandem duplication event within pepper genome. Conserved motif and gene structure analysis revealed that the CaBBXs in the same clade have relatively similar motif arrangements and exon-intron patterns. Expression analysis revealed that the CaBBX genes have different expression levels in various tissues, and some of which were significantly induced during PCI and exogenous salicylic acid (SA) treatment. Among them, CaBBX14 displayed remarkable changed expression during PCI and SA treatment. The silencing of CaBBX14 increases pepper susceptibility to PCI, and also decreases in SA content and expression of pathogenesis-related (PR) and SA-related genes compared with control plants. Together, these findings advance our knowledge base on biological functions of CaBBXs in pepper during PCI through the SA signaling pathway, and we provide an example demonstrating that the potential of CaBBX14 to improve pepper resistance to PCI.
B 盒（BBX）转录因子广泛参与植物的生长、发育以及对各种生物和非生物胁迫的响应。然而，它们在辣椒对辣椒疫霉感染（PCI）的响应中的作用在很大程度上仍未得到探索。在这里，我们总共鉴定了 25 个辣椒 CaBBX 基因，它们在基因组中不均匀分布，验证了它们的特征、系统发育关系、基因结构、保守结构域和表达谱。根据系统发育关系和保守结构域（存在一个或两个 B 盒结构域和 CCT 结构域），将 CaBBX 分为五个主要分支（I 至 V）。基因复制分析表明，在辣椒基因组中存在两个片段复制事件，但没有串联复制事件。保守基序和基因结构分析表明，同一分支中的 CaBBX 具有相对相似的基序排列和外显子-内含子模式。表达分析表明，CaBBX 基因在不同组织中的表达水平不同，其中一些在 PCI 和外源水杨酸（SA）处理期间显著诱导。其中，CaBBX14 在 PCI 和 SA 处理过程中表现出显著变化的表达。CaBBX14 的沉默增加了辣椒对 PCI 的易感性，并且与对照植物相比，SA 含量和病程相关（PR）和 SA 相关基因的表达降低。总之，这些发现通过水杨酸信号通路，推进了我们对 CaBBX 在辣椒 PCI 期间的生物学功能的认识，为 CaBBX14 提高辣椒对 PCI 的抗性提供了一个潜在的例证。
