Cytokinin is a plant hormone and an important regulator of root growth. Reduced cytokinin levels increase root systems, which can be beneficial for crops grown on nutrient poor and/or dry soils. Our study analyzed the effects of increased cytokinin oxidase 5 (OsCKX5) expression in rice roots on root morphology, architecture, and nutrient uptake. We fused the OsCKX5 gene to the strong, root-specific RCc3 rice promoter and overexpressed it in rice plants. The root-specific expression of OsCKX5 in the transgenic plants resulted in positive effects on root development without compromising shoot growth. The root system of the transgenic plants exhibited greater volume, length, projection area, a higher number of tips, and enhanced surface area. OsCKX5 overexpression also resulted in an increased uptake ability of certain macro- and micronutrients, a greater root biomass, deeper root system, and a higher root:shoot ratio, when cultivated on low-fertility soils. We conclude that the enhanced root growth and development by root-specific expression of OsCKX5 could be advantageous for crops grown on oxidic soils in the tropical regions, with a low availability of certain nutrients, especially P and Zn.

细胞分裂素是一种植物激素，是根系生长的重要调节剂。细胞分裂素水平降低会增加根系，这对生长在营养贫乏和/或干燥土壤上的作物有益。我们的研究分析了水稻根中细胞分裂素氧化酶 5 ( OsCKX5 ) 表达增加对根形态、结构和养分吸收的影响。我们将OsCKX5基因与强的根特异性RCc3水稻启动子融合，并在水稻植株中过表达。OsCKX5的根特异表达在转基因植物中对根发育产生积极影响，而不会影响芽生长。转基因植物的根系表现出更大的体积、长度、投影面积、更多的尖端和增加的表面积。当在低肥力土壤上栽培时，OsCKX5过表达还导致某些宏量和微量营养素的吸收能力增加，根生物量更大，根系更深，根：茎比更高。我们得出结论，通过根系特异性表达OsCKX5促进根系生长和发育可能有利于在热带地区生长在氧化土壤上的作物，某些养分，尤其是 P 和 Zn 的可用性较低。