National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China.
National Key Laboratory of Crop Genetic Improvement, National Center of Plant Gene Research (Wuhan), Huazhong Agricultural University, Wuhan 430070, China; Hubei Hongshan Laboratory, Wuhan 430070, China.
J Adv Res. 2023 Mar;45:43-57. doi: 10.1016/j.jare.2022.05.010. Epub 2022 May 29.
Cadmium (Cd), one of the major toxic heavy metals, causes severe deleterious effects on all living organisms from prokaryotes to eukaryotes. Cadmium deposition affects bacterial diversity and bacterial population in soil. Cadmium accumulation in plants is mainly controlled by transporters and the resulting Cd enrichment gives rise to phytotoxicity.
This study aimed to mine transporters that control Cd import or accumulation in rice and uncover the underlying mechanisms that how accumulated Cd poses risks to host plant and leaf bacteria.
RNA-seq analysis, histochemical assays, and elemental quantification were carried out to reveal the biological roles of OsABCG43 for Cd import. Pathogen inoculation, IC value, and bacterial virulence assays were conducted to disclose the effects of Cd on leaf bacteria.
OsABCG43 is characterized as a Cd importer controlling Cd accumulation in rice. OsABCG43 was induced under Cd stress and specifically expressed in the vasculature of leaves and roots. Overexpression of OsABCG43 caused Cd accumulation which inhibits photosynthesis and development and alters the antioxidant system, resulting in phytotoxicity. Moreover, overexpression of OsABCG43 resulted in retarded plant growth and enhanced rice sensitivity to Cd stress. Numerous differentially expressed genes were identified via RNA-seq analysis between the OsABCG43-overexpressing plants and wild type, which functioned in Cd or reactive oxygen species (ROS) homeostasis. In addition, OsABCG43 transcripts were induced by leaf bacteria Xanthomonas oryzae pv. oryzicola (Xoc) and X. oryzae pv. oryzae (Xoo). The enriched Cd directly impaired the formation of virulence factors for the leaf bacteria, preventing colonization or proliferation of Xoc or Xoo in rice leaves.
This work reveals that OsABCG43 is expressed specifically in the vascular and plasma membrane-localized OsABCG43 functions as a Cd importer. OsABCG43-mediated import of Cd is harmful for both rice and the corresponding leaf bacteria.
镉（Cd）是主要的有毒重金属之一，对原核生物到真核生物等所有生物都有严重的有害影响。镉的沉积会影响土壤中的细菌多样性和种群。植物对镉的积累主要受转运蛋白的控制，而积累的 Cd 会导致植物毒性。
本研究旨在挖掘控制水稻中 Cd 摄取或积累的转运蛋白，并揭示积累的 Cd 如何对宿主植物和叶片细菌构成风险的潜在机制。
进行 RNA-seq 分析、组织化学测定和元素定量，以揭示 OsABCG43 对 Cd 摄取的生物学作用。进行病原体接种、IC 值和细菌毒力测定，以揭示 Cd 对叶片细菌的影响。
OsABCG43 是一种 Cd 转运蛋白，控制水稻中 Cd 的积累。OsABCG43 在 Cd 胁迫下被诱导，并特异性表达在叶片和根部的脉管系统中。过表达 OsABCG43 导致 Cd 积累，从而抑制光合作用和发育，并改变抗氧化系统，导致植物毒性。此外，过表达 OsABCG43 导致植物生长迟缓，增强了水稻对 Cd 胁迫的敏感性。通过 OsABCG43 过表达植物与野生型之间的 RNA-seq 分析，鉴定出许多在 Cd 或活性氧（ROS）稳态中发挥作用的差异表达基因。此外，OsABCG43 转录本被叶片细菌稻黄单胞菌 pv。oryzicola（Xoc）和稻黄单胞菌 pv。oryzae（Xoo）诱导。富集的 Cd 直接损害了叶片细菌毒力因子的形成，阻止了 Xoc 或 Xoo 在水稻叶片中的定殖或增殖。
本研究揭示了 OsABCG43 特异性表达在血管和质膜中，OsABCG43 作为 Cd 转运蛋白发挥作用。OsABCG43 介导的 Cd 摄取对水稻和相应的叶片细菌都有害。
