《植物生理学报》 2023, 59(2): 303-314

梨PbSKOR基因参与植株K⁺吸收的功能分析

申长卫^1,*，袁敬平²，李道涵²，李鑫²，董彩霞³

¹河南科技学院资源与环境学院, 河南新乡453003；²河南科技学院园艺园林学院, 河南新乡453003；³南京农业大学江苏省固体有机废弃物资源化高技术研究重点实验室/江苏省有机固体废弃物协同创新中心/教育部资源节约型肥料工程技术研究中心/资源与环境科学学院, 南京210095

通信作者：申长卫；E-mail: changweishen@163.com

摘　要：

钾素(K)是保障梨果高产和优质的关键元素, 土壤缺钾会导致果实品质严重下降, 而钾离子通道基因在草本植物响应外界供钾水平、控制体内钾离子吸收和运输中起关键作用, 但在木本植物中该基因的功能和分子机制尚不清楚。本研究前期通过RNA-Seq技术从‘黄冠梨’中筛选到一个中柱外向整流型钾离子通道基因PbSKOR, 生物信息学表明PbSKOR蛋白质含有1个典型的离子跨膜结构域PF00520, 在烟草的瞬时表达发现该蛋白质定位在细胞膜上。系统发育分析表明该蛋白与苹果MdSKOR同源关系最近。研究发现在高钾和低钾胁迫下, PbSKOR-过表达拟南芥植株根系中PbSKOR基因的表达水平都显著高于叶片, 表明PbSKOR基因具有组织特异性表达的特点。无论低钾胁迫还是高钾胁迫下, PbSKOR-过表达拟南芥植株根系和叶片中的生物量、钾素含量和钾素积累量都显著高于野生型拟南芥和skor突变体拟南芥, 这说明PbSKOR过表达能够增强拟南芥植株应对外界高钾和低钾胁迫的能力, 提高K⁺吸收, 调节植株体内K⁺的平衡和渗透势。基于以上分析推测该基因将会在梨树钾素高效吸收新品种选育和应对外界非生物胁迫中发挥重要作用。

关键词：梨; PbSKOR; 钾通道蛋白; 过表达; 非生物胁迫

收稿：2022-10-10   修定：2022-11-28

资助：河南省青年科学基金(222300420160)和河南科技学院2017年高层次人才引进启动项目(2017034)。

Functional analysis of PbSKOR gene involved in K⁺ absorption in pear

SHEN Changwei^1,*, YUAN Jingping², LI Daohan², LI Xin², DONG Caixia³

¹School of Resources and Environmental Sciences, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China; ²School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Xinxiang, Henan 453003, China; ³Jiangsu Provincial Key Lab of Solid Organic Waste Utilization /Jiangsu Collaborative Innovation Center of Solid Organic Wastes / Educational Ministry Engineering Center of Resource-Saving Fertilizers / College of Resources & Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China

Corresponding author: SHEN Changwei; E-mail: changweishen@163.com

Abstract:

Potassium (K) is the key element that guarantees high yield and high quality of pear. Potassium deficiency in soil will lead to serious decline of fruit quality. Potassium channel genes play a key role in controlling potassium absorption and transport in herbaceous plants in response to external potassium supply levels, but the function and molecular mechanism in woody plants are not yet clear. In the previous study, a stelar K⁺ outward rectifier channel gene PbSKOR was screened from ‘Huangguan’ pear by RNA-Seq technique. Bioinformatics showed that this protein contains a typical ion transmembrane domain, PF00520, which is located on the cell membrane by transient expression in tobacco. Phylogenetic analysis showed that this protein has the highest homology with apple MdSKOR. It was found that the expression level of PbSKOR gene in roots of transgenic plants was significantly higher than that in leaves under high and low potassium stress, indicating that PbSKOR gene had the characteristics of tissue-specific expression. The root and leaf biomass, K⁺ content and K⁺ accumulation of PbSKOR-overexpression transgenic Arabidopsis were higher than those of wild-type and skor mutant Arabidopsis under low or high potassium stress, which indicated that PbSKOR-overexpression could enhance the response of Arabidopsis plants to external high and low potassium stress, improve K⁺ absorption, and regulate the balance and osmotic potential of K⁺. These results speculated that this gene will play an important role in the breeding of new pear varieties with high potassium absorption and response to external abiotic stress.

Key words: pear; PbSKOR; potassium channel; overexpression; abiotic stress