DataSheet1_Unraveling the genomic reorganization of polygalacturonase-inhibiting proteins in chickpea.docx

Polygalacturonase-inhibiting proteins (PGIPs) are cell wall proteins that inhibit pathogen polygalacturonases (PGs). PGIPs, like other defense-related proteins, contain extracellular leucine-rich repeats (eLRRs), which are required for pathogen PG recognition. The importance of these PGIPs in plant defense has been well documented. This study focuses on chickpea (Cicer arietinum) PGIPs (CaPGIPs) owing to the limited information available on this important crop. This study identified two novel CaPGIPs (CaPGIP3 and CaPGIP4) and computationally characterized all four CaPGIPs in the gene family, including the previously reported CaPGIP1 and CaPGIP2. The findings suggest that CaPGIP1, CaPGIP3, and CaPGIP4 proteins possess N-terminal signal peptides, ten LRRs, theoretical molecular mass, and isoelectric points comparable to other legume PGIPs. Phylogenetic analysis and multiple sequence alignment revealed that the CaPGIP1, CaPGIP3, and CaPGIP4 amino acid sequences are similar to the other PGIPs reported in legumes. In addition, several cis-acting elements that are typical of pathogen response, tissue-specific activity, hormone response, and abiotic stress-related are present in the promoters of CaPGIP1, CaPGIP3, and CaPGIP4 genes. Localization experiments showed that CaPGIP1, CaPGIP3, and CaPGIP4 are located in the cell wall or membrane. Transcript levels of CaPGIP1, CaPGIP3, and CaPGIP4 genes analyzed at untreated conditions show varied expression patterns analogous to other defense-related gene families. Interestingly, CaPGIP2 lacked a signal peptide, more than half of the LRRs, and other characteristics of a typical PGIP and subcellular localization indicated it is not located in the cell wall or membrane. The study’s findings demonstrate CaPGIP1, CaPGIP3, and CaPGIP4’s similarity to other legume PGIPs and suggest they might possess the potential to combat chickpea pathogens.

多聚半乳糖醛酸酶抑制蛋白（Polygalacturonase-inhibiting proteins, PGIPs）是一类可抑制病原菌多聚半乳糖醛酸酶（pathogen polygalacturonases, PGs）的细胞壁蛋白。与其他防卫相关蛋白类似，PGIPs含有胞外富亮氨酸重复序列（extracellular leucine-rich repeats, eLRRs），该结构是识别病原菌PG所必需的。这类PGIPs在植物防卫中的重要性已得到充分证实。本研究聚焦于鹰嘴豆（Cicer arietinum）PGIPs（CaPGIPs），原因在于这一重要作物相关的研究信息仍较为有限。本研究鉴定出两个新型CaPGIPs（CaPGIP3与CaPGIP4），并对该基因家族全部4个CaPGIPs进行了计算生物学表征，其中包括此前已报道的CaPGIP1与CaPGIP2。研究结果显示，CaPGIP1、CaPGIP3与CaPGIP4蛋白均带有N端信号肽，包含10个LRR结构域，其理论分子量与等电点均与其他豆科PGIPs相近。系统发育分析与多序列比对结果表明，CaPGIP1、CaPGIP3与CaPGIP4的氨基酸序列与已报道的其他豆科PGIPs具有较高相似性。此外，CaPGIP1、CaPGIP3与CaPGIP4基因的启动子区域中存在多种典型顺式作用元件，涵盖病原菌响应、组织特异性活性、激素响应以及非生物胁迫相关元件。亚细胞定位实验结果显示，CaPGIP1、CaPGIP3与CaPGIP4定位于细胞壁或细胞膜。对未处理条件下的CaPGIP1、CaPGIP3与CaPGIP4基因转录水平进行分析，结果显示其表达模式存在差异，且与其他防卫相关基因家族的表达模式类似。值得注意的是，CaPGIP2缺乏信号肽、超过半数的LRR结构域以及典型PGIP的其他特征，且亚细胞定位结果表明其并未定位于细胞壁或细胞膜。本研究结果证实CaPGIP1、CaPGIP3与CaPGIP4与其他豆科PGIPs具有相似特征，提示它们可能具备抵御鹰嘴豆病原菌的潜力。