Biotechnology Research Institute, Chinese Academy of Agricultural Science, Beijing 100081, China; Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China; Key Laboratory of Forage and Endemic Crop Biotechnology, Ministry of Education, School of Life Sciences, Inner Mongolia University, Hohhot, China.
Key Laboratory of Hainan Province for Postharvest Physiology and Technology of Tropical Horticultural Products, South Subtropical Crops Research Institute, Chinese Academy of Tropical Agricultural Sciences, Zhanjiang, China.
Plant Physiol Biochem. 2024 May;210:108623. doi: 10.1016/j.plaphy.2024.108623. Epub 2024 Apr 11.
Folates are essential to the maintenance of normal life activities in almost all organisms. Proton-coupled folate transporter (PCFT), belonging to the major facilitator superfamily, is one of the three major folate transporter types widely studied in mammals. However, information about plant PCFTs is limited. Here, a genome-wide identification of maize PCFTs was performed, and two PCFTs, ZmMFS_1-62 and ZmMFS_1-73, were functionally investigated. Both proteins contained the typical 12 transmembrane helixes with N- and C-termini located in the cytoplasm, and were localized in the plasma membrane. Molecular docking analysis indicated their binding activity with folates via hydrogen bonding. Interference with ZmMFS_1-62 and ZmMFS_1-73 in maize seedlings through virus-induced gene silencing disrupted folate homeostasis, mainly in the roots, and reduced tolerance to drought and salt stresses. Moreover, a molecular chaperone protein, ZmHSP20, was found to interact with ZmMFS_1-62 and ZmMFS_1-73, and interference with ZmHSP20 in maize seedlings also led to folate disruption and increased sensitivity to drought and salt stresses. Overall, this is the first report of functional identification of maize PCFTs, which play essential roles in salt and drought stress tolerance, thereby linking folate metabolism with abiotic stress responses in maize.
叶酸对于几乎所有生物体的正常生命活动都是必不可少的。质子偶联叶酸转运蛋白（PCFT）属于主要易化超家族，是哺乳动物中广泛研究的三种主要叶酸转运蛋白类型之一。然而，关于植物 PCFT 的信息有限。本研究进行了玉米 PCFT 的全基因组鉴定，并对其中的两个 PCFT，ZmMFS_1-62 和 ZmMFS_1-73，进行了功能研究。这两种蛋白均含有典型的 12 个跨膜螺旋，N 端和 C 端位于细胞质中，定位于质膜上。分子对接分析表明它们通过氢键与叶酸结合。通过病毒诱导的基因沉默干扰玉米幼苗中的 ZmMFS_1-62 和 ZmMFS_1-73 会破坏叶酸稳态，主要在根部，并降低对干旱和盐胁迫的耐受性。此外，还发现一种分子伴侣蛋白 ZmHSP20 与 ZmMFS_1-62 和 ZmMFS_1-73 相互作用，干扰玉米幼苗中的 ZmHSP20 也会导致叶酸紊乱，并增加对干旱和盐胁迫的敏感性。总之，这是首次对玉米 PCFT 的功能进行鉴定，它们在耐盐和耐旱性方面发挥着重要作用，从而将叶酸代谢与玉米的非生物胁迫反应联系起来。
