基于SLAF-seq技术鉴定苹果砧木耐涝候选基因

[背景]苹果(Malus×domestica Borkh)是我国主要栽培果树树种之一,但部分苹果产区由于夏、秋季的大量集中降雨和排水不良等造成果园涝害频繁发生,导致苹果树叶片黄化、脱落,果实品质和产量下降.[目的]鉴定苹果耐涝相关基因,为苹果耐涝分子标记辅助育种和优质高产栽培提供依据.[方法]以耐涝苹果砧木G41和不耐...

Identification of Candidate Genes for Waterlogging Tolerance in Apple Rootstock by Using SLAF-seq Technique

【Background】 Apple (Malus×domestica Borkh) is one of the most cultivated fruit crops in China. While apple trees frequently encounter waterlogging stress mainly due to excess rainfall and poor soil drainage, resulting in yellowing leaf, declined fruit quality and yield in summer and autumn. 【Objective】 The aim of this study was to identify waterlogging-tolerant genes of apple, so as to provide a basis for waterlogging tolerance molecular marker assisted breeding, high-quality and high-yield cultivation of apple.【Method】In this study, 50 waterlogging-tolerant plants and 50 waterlogging-sensitive plants were selected to construct two bulked DNA pools from the 495 F₁ population, which were derived from a cross of the waterlogging-tolerant apple rootstock G41 and the waterlogging-tolerant M. sieverii (Ledeb) Roem. Specific-locus amplified fragment (SLAF) labels and single nucleotide polymorphism (SNP) markers were developed by SLAF-seq technique. The mapping and candidate gene prediction of waterlogging tolerance in apple were carried out by combining apple genome and genetic association analysis, and the relative expression of the candidate gene was also analyzed in different waterlogging tolerance plants under waterlogging stress.【Result】A total of 119 072 SLAF labels were obtained, of which, 11 133 were polymorphic between both parents. A total 16 237 071 SNPs were identified by sequence analysis, including 170 617 SNPs with polymorphic. By association analysis with Eudidean distance (ED) and SNP-index, a candidate locus was found to be strongly associated with waterlogging tolerance, which was a region of 1.94-3.25 Mb on apple chromosome 10. The associated region was 1.31 Mb that contained 120 genes, and functional annotation of the genes in this region revealed a gene MD10G1014500, alcohol dehydrogenase gene (ADH1) related to respiratory metabolism. The expression level of ADH1 gene in waterlogging tolerant plants was significantly higher than that in waterlogging sensitive plants at 1, 2, 4 and 6 days after waterlogging treatment. 【Conclusion】 One gene (MD10G1014500) was identified as a potential candidate gene involved waterlogging tolerance of apple, which located in a 1.94-3.25 Mb interval on chromosome 10. These findings laid the foundation for gene cloning and functional analysis for waterlogging tolerance of apple.