Key Laboratory of Biology and Genetic Improvement of Oil Crops, The Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China.
College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
Int J Mol Sci. 2021 Nov 26;22(23):12792. doi: 10.3390/ijms222312792.
The proteins of membrane transporters (MTs) are embedded within membrane-bounded organelles and are the prime targets for improvements in the efficiency of water and nutrient transportation. Their function is to maintain cellular homeostasis by controlling ionic movements across cellular channels from roots to upper plant parts, xylem loading and remobilization of sugar molecules from photosynthesis tissues in the leaf (source) to roots, stem and seeds (sink) via phloem loading. The plant's entire source-to-sink relationship is regulated by multiple transporting proteins in a highly sophisticated manner and driven based on different stages of plant growth and development (PG&D) and environmental changes. The MTs play a pivotal role in PG&D in terms of increased plant height, branches/tiller numbers, enhanced numbers, length and filled panicles per plant, seed yield and grain quality. Dynamic climatic changes disturbed ionic balance (salt, drought and heavy metals) and sugar supply (cold and heat stress) in plants. Due to poor selectivity, some of the MTs also uptake toxic elements in roots negatively impact PG&D and are later on also exported to upper parts where they deteriorate grain quality. As an adaptive strategy, in response to salt and heavy metals, plants activate plasma membranes and vacuolar membrane-localized MTs that export toxic elements into vacuole and also translocate in the root's tips and shoot. However, in case of drought, cold and heat stresses, MTs increased water and sugar supplies to all organs. In this review, we mainly review recent literature from Arabidopsis, halophytes and major field crops such as rice, wheat, maize and oilseed rape in order to argue the global role of MTs in PG&D, and abiotic stress tolerance. We also discussed gene expression level changes and genomic variations within a species as well as within a family in response to developmental and environmental cues.
膜转运蛋白（MTs）的蛋白质嵌入在膜结合的细胞器中，是提高水和养分运输效率的主要目标。它们的功能是通过控制细胞通道中的离子运动来维持细胞内环境的稳定，这些通道从根部到植物上部、木质部装载和从光合作用组织中糖分子的再动员（源）到根部、茎和种子（汇），通过韧皮部装载。植物的整个源到汇关系是通过多种转运蛋白以高度复杂的方式调节的，并根据植物生长和发育（PG&D）的不同阶段和环境变化来驱动。MTs 在 PG&D 中起着至关重要的作用，可增加植物高度、分枝/分蘖数、增强每株植物的数量、长度和充实的穗数、种子产量和谷物质量。动态气候变化扰乱了植物中的离子平衡（盐、干旱和重金属）和糖供应（冷和热应激）。由于选择性差，一些 MTs 也在根部吸收有毒元素，对 PG&D 产生负面影响，随后也被运到上部，在那里它们会恶化谷物质量。作为一种适应策略，植物会对盐和重金属做出反应，激活质膜和液泡膜定位的 MTs，将有毒元素输出到液泡中，并在根部尖端和茎部进行转运。然而，在干旱、寒冷和热应激的情况下，MTs 会增加所有器官的水分和糖供应。在这篇综述中，我们主要回顾了来自拟南芥、盐生植物和主要大田作物（如水稻、小麦、玉米和油菜）的最新文献，以论证 MTs 在 PG&D 和非生物胁迫耐受性方面的全球作用。我们还讨论了基因表达水平变化和物种内以及家族内的基因组变异，以响应发育和环境线索。
