College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China.
College of Horticulture, China Agricultural University, Beijing, 100193, PR China; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (Nutrition and Physiology), Ministry of Agriculture and Rural Affairs, Beijing, 100193, PR China.
Plant Physiol Biochem. 2022 Oct 15;189:94-103. doi: 10.1016/j.plaphy.2022.08.017. Epub 2022 Aug 27.
Iron (Fe) deficiency affects plant growth and development. The proton pump interactor (PPI) in plants responds to multiple abiotic stresses, although it has not been well characterized under Fe deficiency stress. In this study, we systematically identified and analyzed the PPI gene family in apple. Three PPI candidate genes were found, and they contained 318-1349 amino acids and 3-7 introns. Under Fe deficiency stress, we analyzed the expression of all the PPI genes in roots of apple rootstock Malus xiaojinensis. Expression of the gene MD11G1247800, designated PPI1, is obviously induced by Fe deficiency treatment in M. xiaojinensis. We first cloned MxPPI1 from M. xiaojinensis and determined its subcellular localization, which indicated that it is localized in the cell membrane and nucleus in tobacco. We found that the level of expression of the MxPPI1 protein increased significantly under Fe deficiency stress in apple calli. Moreover, overexpressing MxPPI1 in apple calli enhanced the activities of ferric chelate reductase and H-ATPase, H secretion, MxHA2 gene expression and total Fe content when compared with the wild type calli. We further found that MxPPI1 interacted with MxHA2 using bimolecular fluorescence complementation and luciferase complementation assays. Overall, we demonstrated that MxPPI1 interacts with MxHA2 to enhance the activity of H-ATPase to regulate Fe absorption in M. xiaojinensis.
铁（Fe）缺乏会影响植物的生长和发育。质子泵相互作用蛋白（PPI）在植物中对多种非生物胁迫作出响应，尽管在 Fe 缺乏胁迫下其特征尚未得到很好的描述。在本研究中，我们系统地鉴定和分析了苹果中的 PPI 基因家族。发现了 3 个 PPI 候选基因，它们包含 318-1349 个氨基酸和 3-7 个内含子。在 Fe 缺乏胁迫下，我们分析了苹果砧木小金海棠根系中所有 PPI 基因的表达。基因 MD11G1247800 的表达，命名为 PPI1，在小金海棠中明显被 Fe 缺乏处理诱导。我们首次从小金海棠中克隆了 MxPPI1，并确定了其亚细胞定位，表明它定位于烟草的细胞膜和细胞核中。我们发现，在苹果愈伤组织中，MxPPI1 蛋白的表达水平在 Fe 缺乏胁迫下显著增加。此外，与野生型愈伤组织相比，在苹果愈伤组织中过表达 MxPPI1 增强了铁螯合还原酶和 H-ATPase 的活性、H 分泌、MxHA2 基因表达和总 Fe 含量。我们进一步发现 MxPPI1 与 MxHA2 相互作用，使用双分子荧光互补和荧光素酶互补测定法。总的来说，我们证明了 MxPPI1 与 MxHA2 相互作用，增强了 H-ATPase 的活性，从而调节小金海棠中铁的吸收。
