| Almond,as an important dried fruit,has good economic value,nutritional value and medical value.The cold resistance of almond in China is not strong,the suitable growing area is narrow,and it can’t meet the diversified demand of the market.The high value of almond and the lack of market require breeders to cultivate new varieties of almond with high quality,high yield and strong adaptability.Population genetic analysis of almond and cloning of key enzyme genes for lignin synthesis can provide theoretical basis for molecular breeding of almond,which is of great significance for speeding up the breeding efficiency of almond.In this study,based on the second-generation sequencing technology,the whole genome of excellent seedlings and traditional main cultivars of almond were resequenced,and then the population evolution and population selection analysis were carried out based on SNP molecular markers,and then the key enzyme genes of lignin synthesis were found for gene cloning and bioinformatics analysis.Finally,the following conclusions are obtained:1.1,088,481 high-quality SNP loci were obtained by mutation detection,and 81,556 SNP loci were located in exon region,with the highest number and average density of SNP loci on Chr1 chromosome;Genetic evolution analysis of 38 individual almond trees shows that the phylogenetic tree can divide individual almond trees into four groups,and the first group can be divided into the first group,and the second,third and fourth groups can be divided into the second group by combining population structure and principal component analysis.1,No.14 and No.18 are closely related to varieties ’ifeng’ and ’Wanfeng’,No.16,No.21 and No.22 are closely related to ’Shuangguo’,No.13 is closely related to ’Zhipi’,No.8 is closely related to ’Shitoubadan’,and No.19 is closely related to ’Yeerqiang’(see page 11 for the number of single plants2.According to the results of genetic evolution analysis,almond individual plants are divided into two groups: A and B(see 3.1.1 on page 26 for details of individual plants in groups A and B).Through the analysis of population selection of groups A and B,it can be seen that there is great genetic differentiation on Chr2 and Chr3 chromosomes in groups A and B,but little difference on chromosome Chr5;Based on the intersection of the first 10%,the first 5% and the first 1% regions of ROD and Fst,selective elimination analysis was carried out,and 1058,306 and 8 protein-coding genes were obtained,respectively.The functions of the selected genes from the top 10% and the top 5% were analyzed.Their functions were mainly steroid synthesis and metabolism,lipid synthesis and metabolism,brassinosteroid,hormone response,oxidoreductase activity,glycosyltransferase activity,etc.3.Two genes,CCAOMT and CAD,were cloned from the single plants of Thin Shell No.8 and Thick Shell No.15.The cloned genes were named 8P-CCo AOMT,15P-CCo AOMT,8P-CAD and 15P-CAD.The amino acid numbers of proteins encoded by the four genes are 98,98,299 and 305 respectively.The corresponding proteins of 8P-CCo AOMT and 15P-CCo AOMT are hydrophobic stable proteins,while the corresponding proteins of 8P-CAD and 15P-CAD are hydrophilic unstable proteins.On the third-level structure,the spatial structures of 8P-CCo AOMT and 15P-CCo AOMT,8P-CAD and 15P-CAD are highly similar.Phylogenetic tree based on these four genes showed that almond was well clustered with Prunus peach,sweet cherry,apricot and plum,which indicated that they had strong homology. |
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