Glycerophosphodiester phosphodiesterase 1 (GDPD1) plays an important function in the abiotic stress responses and participates in the accumulation of sn-glycerol-3-phosphate (G3P) in plants, which is key to plant systemic acquired resistance (SAR). However, the role of GDPD1 in plant responses to biotic stress remains poorly understood. This study characterized the antivirus function of the GDPD1 gene (designated as ClGDPD1) from Eureka lemon. ClGDPD1 is located in the membrane and endoplasmic reticulum, where it interacts with the citrus yellow vein clearing virus (CYVCV) coat protein (CP). Compared to individually express ClGDPD1 or co-expressed ClGDPD1 + CP140-326, transiently co-expressed ClGDPD1 + CP or ClGDPD1 + CP1-139 significantly up-regulated the key substance contents and genes expression involved in glycerophospholipid metabolism. Over-expression of ClGDPD1 significantly facilitated the accumulation of G3P, up-regulated the expression of SAR-related genes, and increased the resistance of transgenic Eureka lemon to CYVCV infection. Furthermore, exogenous glycerol treatment and over-expression of ClGPDH increased the G3P content and reduced CYVCV titers in plants or hairy roots. These results indicated that the enhanced resistance of ClGDPD1 transgenic Eureka lemon to CYVCV may be due to facilitating G3P accumulation through the interaction of ClGDPD1 with CP. Our findings provide novel insights into the role of ClGDPD1 as an important regulatory center in mediating the citrus defense response to viral infections.

中文翻译：

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甘油磷酸二酯磷酸二酯酶 1 介导尤里卡柠檬对柑橘黄脉清除病毒的抗性 G3P 积累


甘油磷酸二酯磷酸二酯酶 1 （GDPD1） 在非生物胁迫反应中起重要作用，并参与植物体内 sn-甘油-3-磷酸 （G3P） 的积累，这是植物系统获得性抗性 （SAR） 的关键。然而，GDPD1 在植物对生物胁迫的反应中的作用仍然知之甚少。本研究表征了尤里卡柠檬 GDPD1 基因 （指定为 ClGDPD1） 的抗病毒功能。ClGDPD1 位于膜和内质网中，与柑橘黄静脉清除病毒 （CYVCV） 外壳蛋白 （CP） 相互作用。与单独表达 ClGDPD1 或共表达 ClGDPD1 + CP140-326 相比，瞬时共表达 ClGDPD1 + CP 或 ClGDPD1 + CP1-139 显着上调参与甘油磷脂代谢的关键物质含量和基因表达。ClGDPD1 的过表达显著促进了 G3P 的积累，上调了 SAR 相关基因的表达，并增加了转基因 Eureka 柠檬对 CYVCV 感染的抵抗力。此外，外源甘油处理和 ClGPDH 过表达增加了植物或毛状根中的 G3P 含量并降低了 CYVCV 滴度。这些结果表明，ClGDPD1 转基因 Eureka 柠檬对 CYVCV 的抗性增强可能是由于 ClGDPD1 与 CP 的相互作用促进了 G3P 积累。我们的研究结果为 ClGDPD1 作为介导柑橘对病毒感染的防御反应中的重要调节中心的作用提供了新的见解。