应用病毒诱导基因沉默技术研究棉花GhAKT1和GhKT2基因的功能  

Functional Characterization of GhAKT1 and GhKT2 in Cotton(Gossypium hirsutum L.)Using Virus-Induced Gene Silencing

作　　者：穆春[1] 安静[1] 李婷婷[1] 王逸茹[1] 张明才[1] 田晓莉[1] Mu Chun An Jing Li Tingting Wang Yim Zhang Mingcai Tian Xiaoli(State Key Laboratory of Plant Physiology and Biochemistry / Engineering Research Center of Plant Growth Regulator, Ministry of Education / College of Agronomy, China Agricultural University, Beijing 100193, China)

机构地区：[1]植物生理学与生物化学国家重点实验室/植物生长调节剂教育部工程研究中心/中国农业大学农学院,北京100193

出　　处：《棉花学报》2017年第1期40-49,共10页Cotton Science

基　　金：国家科技重大专项--转基因生物新品种培育(2014ZX08005-004-008)

摘　　要：【目的】本研究旨在揭示棉花钾离子(K^+)吸收机制。【方法】以国欣棉3号和中棉所41为材料,应用病毒诱导基因沉默技术研究棉花K^+通道基因GhAKT1和K^+转运体基因GhKT2的功能。【结果】在低水平供K^+(0.1 mmol·L^(-1))和充分供K^+(2.5 mmol·L^(-1))条件下,沉默GhAKT1和GhKT2基因使棉花幼苗的K^+积累量分别降低15%左右和25%以上。此外,沉默GhAKT1和GhKT2基因导致棉花幼苗对K^+的最大吸收速率和亲和能力出现不同程度的下降。药理学试验结果表明,在外界K^+浓度低于250μmol·L^(-1)的条件下,高亲和系统对棉花K^+吸收的贡献大于K^+通道;而且GhAKT1蛋白可能是1个对NH4+比较敏感的组分。【结论】棉花K^+通道蛋白GhAKT1和K^+转运体蛋白GhKT2具有吸收K^+的功能,而且表现出双亲和吸收K^+的特性,可作为改善棉花钾营养的候选基因。[Objective] The objective of this study was to reveal the mechanism underlying potassium （K＋） uptake in cotton. [Method] We used virus-induced gene silencing to examine the functions of the K＋ channel （GbAKT1） and K＋ transporter （GhKT2） genes in two cotton cultivars, namely Guoxin 3 and CCRI 41. [Results] The silencing of these two genes decreased K＋ levels by about 15% and more than 25% at low （0.1 mmol·L-1） and sufficient （2.5 mmol·L-1） K＋ concentrations, respectively. Regarding the parameters affecting K＋ uptake kinetics, the silencing of GhAKTI and GhKT2 decreased Imax （per root dry weight）, but increased Km to varying levels. Additionally, the results of pharmacological tests indicated that the contribution of a high-affinity K＋ uptake system to the absorption of K＋ is greater than that of K＋ channels in cotton at external K＋ concentrations below 250 μmol. L-1. Furthermore, GhAKT1 activity may be sensitive to NH4＋. [Conclusion] These results suggest that GhAKT1 and GhKT2 are associated with low- and high-affinity K＋ uptake in cotton. These genes may be useful for increasing cotton K＋ contents.

关 键 词：棉花 GhAKT1 GhKT2 K+吸收 

分 类 号：S562[农业科学—作物学]