Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA.
BioDiscovery Institute, University of North Texas, Denton, TX 76203, USA.
J Exp Bot. 2023 Nov 21;74(21):6860-6873. doi: 10.1093/jxb/erad355.
MYZUS PERSICAE-INDUCED LIPASE1 (MPL1) encodes a lipase in Arabidopsis thaliana that is required for limiting infestation by the green peach aphid (GPA; Myzus persicae), an important phloem sap-consuming insect pest. Previously, we demonstrated that MPL1 expression was up-regulated in response to GPA infestation, and GPA fecundity was higher on the mpl1 mutant, compared with the wild-type (WT), and lower on 35S:MPL1 plants that constitutively expressed MPL1 from the 35S promoter. Here, we show that the MPL1 promoter is active in the phloem and expression of the MPL1 coding sequence from the phloem-specific SUC2 promoter in mpl1 is sufficient to restore resistance to GPA. The GPA infestation-associated up-regulation of MPL1 requires CYCLOPHILIN 20-3 (CYP20-3), which encodes a 12-oxo-phytodienoic acid (OPDA)-binding protein that is involved in OPDA signaling, and is required for limiting GPA infestation. OPDA promotes MPL1 expression to limit GPA fecundity, a process that requires CYP20-3 function. These results along with our observation that constitutive expression of MPL1 from the 35S promoter restores resistance to GPA in the cyp20-3 mutant, and MPL1 acts in a feedback loop to limit OPDA levels in GPA-infested plants, suggest that an interplay between MPL1, OPDA, and CYP20-3 contributes to resistance to GPA.
桃蚜诱导的脂肪酶 1（MPL1）在拟南芥中编码一种脂肪酶，该酶对于限制绿桃蚜（GPA；Myzus persicae）的侵害是必需的，GPA 是一种重要的韧皮部汁液消耗性害虫。此前，我们证明 MPL1 的表达在受到 GPA 侵害时会上调，与野生型（WT）相比，mpl1 突变体上的 GPA 繁殖力更高，而组成型表达 MPL1 的 35S：MPL1 植株上的 GPA 繁殖力更低，MPL1 来自 35S 启动子。在这里，我们表明 MPL1 启动子在韧皮部中具有活性，并且在 mpl1 中从韧皮部特异性 SUC2 启动子表达 MPL1 编码序列足以恢复对 GPA 的抗性。MPL1 的 GPA 侵害相关上调需要细胞色素 P45020-3（CYP20-3），它编码一种 12-氧-植物二烯酸（OPDA）结合蛋白，该蛋白参与 OPDA 信号传导，并且对于限制 GPA 的侵害是必需的。OPDA 促进 MPL1 的表达以限制 GPA 的繁殖力，这一过程需要 CYP20-3 功能。这些结果以及我们观察到从 35S 启动子组成型表达 MPL1 可在 cyp20-3 突变体中恢复对 GPA 的抗性，并且 MPL1 在反馈回路中作用以限制 GPA 感染植物中的 OPDA 水平，表明 MPL1、OPDA 和 CYP20-3 之间的相互作用有助于对 GPA 的抗性。
