Annotation Of CACTA Transposable Elements In Two Leguminosae Plants And Development Of Common Bean Molecular Marker

CACTA transposons belong to DNA transposons.As an important part of the plant genome,it plays an important role in promoting the evolution of the genome and genes.Phaseolus vulgaris and Vigna angularis are two important leguminous plants.Because of their high protein,low fat,rich starch and dietary fiber,they have paramount economic value as healthy vegetables and crops.In this paper,the genomic CACTA transposable elements of Phaseolus vulgaris and Vigna angularis were systematically identified and analyzed by means of genomics and bioinformatics.The main research contents the numbers,distribution characteristics,insertion preference,phylogeny and functional gene relationship.In addition,molecular labeling technology was developed for string beans based on the identified CACTA transposer element,and cluster analysis was carried out to establish the corresponding molecular identity cards of 24 different Phaseolus vulgaris varieties.The purpose of this study is to provide some reference for the annotation of legume genome and CACTA transposon,and to provide data source for screening available transposon molecular markers in Phaseolus vulgaris.The main results are as follows:1.Identification and distribution of CACTA transposable elements in two leguminous plantsBased on structural characteristics and homologous alignment methods,we identified 1645 CACTA transposable elements that clearly belong to 20 families,accounting for 0.9%of the Phaseolus vulgaris genome,and 1680 CACTA transposable elements clearly belonging to 16 families in the Vigna angularis genome,accounting for 1.5%of the Vigna angularis genome.The number distribution of CACTA transposable elements on chromosomes of Vigna angularis and Phaseolus vulgaris was more uniform;the length of CACTA transposable elements of two leguminous plants tended to be shorter(<5kb);the insertion sites of CACTA elements in both leguminous plants had a strong bias and were preferentially inserted into the AT region;there was a significant negative correlation between CACTA element density and gene density in genome,but not in Phaseolus vulgaris.2.Phylogenetic Analysis of CACTA transposon in two Leguminosae plantsThrough the evolutionary analysis of CACTA transposase in two leguminous plants,it can be seen that all families are divided into four evolutionary branches.Among them,there is only one family PvES8,of vulgaris in Class Ⅱ branch,while Vigna angularis lacks this branch.In addition,there are great differences in the number of families and elements in each branch of the two leguminous plants.In the Phaseolus vulgaris genome,Class Ⅰ branch has the largest number of families,Class Ⅳ branch has the largest number of elements;in Vigna angularis genome,Class Ⅰ branch occupies the highest proportion both in family number and element number.3.Relationship between CACTA transposons and genes in two Leguminosae plants23.7%and 18.0%of the elements in the genomes of Phaseolus vulgaris and Vigna angularis were inserted within or near the gene(<2kb),respectively,and 258 and 440 elements captured complete genes or gene fragments,respectively,and enriched these genes functionally.The results of functional enrichment of these genes showed that the two legumes had similar enrichment characteristics:cellular component mainly focused on cells,cellular components and organelles;molecular function is mainly focused on catalysis and binding;biological process mainly focuses on the cellular process and metabolic process.4.Development of molecular markers for Phaseolus vulgarisBased on the identified insertion polymorphism of CACTA transposable elements,51 pairs of primers were randomly designed.11 pairs of primers were used to analyze the genetic relationship and construct the molecular identity card of 24 Phaseolus vulgaris varieties.The results showed that the genetic similarity coefficient among materials was between 0.28 and 100,and the average genetic similarity coefficient was 0.64;24 varieties were divided into 4 categories on the genetic similarity coefficient of 0.53;92%of Phaseolus vulgaris varieties could be well distinguished.