Homologous Cloning of Potassium Channel Genes From the Superior Apple Rootstock Line 12-2, Which is Tolerant to Apple Replant Disease.

Yunfei Mao,Xiafei Su,Haiyan Wang,Yangbo Liu,Xiang Shen,Yanli Hu,Yijun Yin,Xiaoqiong Qin ,Xueli Cui

doi:10.3389/fgene.2022.803160

Abstract

Potassium channels are important ion channels that are responsible for the absorption of potassium in the plant nutrient uptake system. In this study, we used homologous molecular cloning to obtain 8 K+ channel genes from the superior apple rootstock line 12-2 (self-named): MsAKT1-1, MsKAT3-2, MsKAT1-3, MsK2P3-4, MsK2P3-5, MsK2P5-6, MsK2P3-7, and MsK2P3-8. Their lengths varied from 942 bp (MsK2P5-6) to 2625 bp (MsAKT1-1), and the number of encoded amino acids varied from 314 (MsK2P5-6) to 874 (MsAKT1-1). Subcellular localization predictions showed that MsAKT1-1, MsKAT3-2, and MsKAT1-3 were localized on the plasma membrane, and MsK2P3-4, MsK2P3-5, MsK2P5-6, MsK2P3-7, and MsK2P3-8 were localized on the vacuole and plasma membrane. The 8 K+ channel proteins contained α helices, extended strands, β turns, and random coils. MsKAT1-3 had four transmembrane structures, MsKAT3-2 had six, and the other six K+ channel genes had five. Protein structure domain analysis showed that MsAKT1-1 contained nine protein domains, followed by MsKAT3-2 with four, MsKAT1-3 with three, and the other five two-pore domain K+ channel proteins with two. Semi-quantitative RT-PCR detection of the K+ channel genes showed that their expression levels were high in roots. qRT-PCR analysis showed that the relative expression levels of the 8 genes changed after exposure to ARD stress. The above results provide a theoretical basis for further research on the functions of potassium channel genes in 12-2 and a scientific basis for the breeding of ARD-resistant rootstock.

Highlights

Apple replant disease (ARD) refers to the general phenomenon in which the same or closely related crops are continuously planted on the same piece of land, leading to yield reductions, quality deterioration, and impaired growth under normal management (Chen et al, 2020)
Using p1300-GFP as a vector for homologous cloning, 8 K+ channel genes were cloned based on 28 K+ channel gene sequences in apple (Table 1)
The results showed that the gene lengths and CDS lengths of the 8 K+ channel genes, and the number of translatable amino acids, unlike other species such as Arabidopsis

Summary

Introduction

Apple replant disease (ARD) refers to the general phenomenon in which the same or closely related crops are continuously planted on the same piece of land, leading to yield reductions, quality deterioration, and impaired growth under normal management (Chen et al, 2020). The replanting of old orchards is becoming more and more common, and major appleproducing areas in the world are facing ARD (Mazzola and Manici, 2012). About 50% of the apple orchards in the United Kingdom, New Zealand, and Poland have ARD (Manici et al, 2013). ARD can lead to poor growth of new roots, slow growth, short plants, reduced resistance, disease, and death of the entire plant, leading to severe economic repercussions (Narwal 2010). Strategies for effectively ameliorating the effects of ARD on apple are urgently needed

Methods

Results

Discussion

Conclusion