Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, 835215, Jharkhand, India.
Division of Genetics, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
Protoplasma. 2023 May;260(3):723-739. doi: 10.1007/s00709-022-01808-4. Epub 2022 Sep 13.
The TRANSPORT INHIBITOR RESPONSE 1/AUXIN SIGNALING F-BOX (TIR1/AFB) protein serves as auxin receptor and links with Aux/IAA repressor protein leading to its degradation via SKP-Cullin-F box (SCF) complex in the auxin signaling pathway. Present study revealed 11 TIR1/AFB genes in wheat by genome-wide search using AFB HMM profile. Phylogenetic analysis clustered these genes in two classes. Several phytohormone, abiotic, and biotic stress responsive cis-elements were detected in promoter regions of TIR1/AFB genes. These genes were localized on homoeologous chromosome groups 2, 3, and 5 showing orthologous relation with other monocot plants. Most genes were interrupted by introns and the gene products were localized in cytoplasm, nucleus, and cell organelles. TaAFB3, TaAFB5, and TaAFB8 had nuclear localization signals. The evolutionary constraint suggested paralogous sister pairs and orthologous genes went through strong purifying selection process and are slowly evolving at protein level. Functional annotation revealed all TaAFB genes participated in auxin activated signaling pathway and SCF-mediated ubiquitination process. Furthermore, in silico expression study revealed their diverse expression profiles during various developmental stages in different tissues and organs as well as during biotic and abiotic stress. QRT-PCR based studies suggested distinct expression pattern of TIR1-1, TIR1-3, TaAFB1, TaAFB2, TaAFB3, TaAFB4, TaAFB5, TaAFB7, and TaAFB8 displaying maximum expression at 24 and 48 h post inoculation in both susceptible and resistant near isogenic wheat lines infected with leaf rust pathogen. Importantly, this also reflects coordinated responses in expression patterns of wheat TIR1/AFB genes during progression stages of leaf rust infection.
转运抑制剂反应 1/生长素信号 F-box（TIR1/AFB）蛋白作为生长素受体，与Aux/IAA 阻遏蛋白结合，导致其通过生长素信号通路中的 SKP-Cullin-F 盒（SCF）复合物降解。本研究通过使用 AFB HMM 轮廓对小麦基因组进行全基因组搜索，发现了 11 个 TIR1/AFB 基因。系统发育分析将这些基因分为两类。在 TIR1/AFB 基因启动子区检测到几种植物激素、非生物和生物胁迫响应顺式元件。这些基因定位于同源染色体组 2、3 和 5 上，与其他单子叶植物具有同源关系。大多数基因被内含子打断，基因产物定位于细胞质、细胞核和细胞细胞器中。TaAFB3、TaAFB5 和 TaAFB8 具有核定位信号。进化约束表明，旁系姐妹对和直系基因经历了强烈的纯化选择过程，在蛋白质水平上缓慢进化。功能注释表明，所有 TaAFB 基因都参与了生长素激活的信号通路和 SCF 介导的泛素化过程。此外，计算机表达研究表明，它们在不同组织和器官的不同发育阶段以及生物和非生物胁迫下表现出多样化的表达谱。基于 QRT-PCR 的研究表明，TIR1-1、TIR1-3、TaAFB1、TaAFB2、TaAFB3、TaAFB4、TaAFB5、TaAFB7 和 TaAFB8 在感染叶锈病病原体的感病和抗病近等基因系小麦中的表达模式存在明显差异，在接种后 24 和 48 小时达到最大值。重要的是，这也反映了小麦 TIR1/AFB 基因在叶锈病感染进展阶段表达模式的协调反应。
