Expression characteristics of <i>CsPG23</i> in citrus and analysis of its interacting protein

Exploring the resistance genes of citrus to Huanglongbing (HLB) is the foundation and key to citrus disease-resistant breeding. Through the analysis of comparative transcriptome data, we identified six cell wall degradation genes that respond to citrus infection with <i>Ca</i>Las. We selected one of the genes with high differential expression levels and cloned it, naming it <i>CsPG23</i>. The subcellular localization results of tobacco indicated that the <i>CsPG23</i> protein is localized in the nucleus, cytoplasm, and cell membrane. Real-time fluorescence quantitative PCR (RT-qPCR) analysis showed that the expression of <i>CsPG23</i> is related to variety tolerance, tissue location, and symptom development. In addition, we constructed overexpression and silencing vectors for <i>CsPG23</i> and obtained <i>CsPG23</i> silencing plants, overexpression and silencing hairy roots, and analyzed the expression characteristics of <i>CsPG23</i> in response to SA, JA, MeSA and H₂O₂ induction through RT-qPCR. Using Protein–Protein Interaction (PPI) to predict and screen for a citrus protein CsAGD8 that may interact with CsPG23, and preliminarily verifying its interaction with CsPG23 protein through Yeast Two-hybrid (Y2H). We constructed overexpression and silencing vectors for <i>CsAGD8</i> and obtained <i>CsAGD8</i> overexpression and silencing hairy roots. In summary, it is indicated that CsPG23 may interact with CsAGD8 in response to <i>Ca</i>Las infection.探索柑橘抗黄龙病（Huanglongbing, HLB）的抗性基因是柑橘抗病育种的基础与核心。本研究通过比较转录组数据分析，鉴定出6个响应柑橘受*Ca*Las侵染的细胞壁降解基因。从中选取1个差异表达水平较高的基因进行克隆，将其命名为*CsPG23*。烟草亚细胞定位实验结果显示，*CsPG23*蛋白定位于细胞核、细胞质与细胞膜。实时荧光定量PCR（Real-time fluorescence quantitative PCR, RT-qPCR）分析表明，*CsPG23*的表达与品种耐性、组织定位及症状发育密切相关。此外，本研究构建了*CsPG23*的过表达与沉默载体，获得了*CsPG23*沉默植株、过表达及沉默毛状根，并通过RT-qPCR分析了*CsPG23*在水杨酸（SA）、茉莉酸（JA）、水杨酸甲酯（MeSA）及过氧化氢（H₂O₂）诱导下的表达特性。通过蛋白质相互作用（Protein–Protein Interaction, PPI）预测筛选出可与CsPG23互作的柑橘蛋白CsAGD8，并借助酵母双杂交（Yeast Two-hybrid, Y2H）技术初步验证了二者的互作关系。本研究还构建了*CsAGD8*的过表达与沉默载体，获得了*CsAGD8*过表达及沉默毛状根。综上，结果表明CsPG23可能与CsAGD8互作以响应*Ca*Las侵染。