Identification Of LTR Retrotransposons Elements With Env Structure In Nine Legume Species And Development Of RBIP Molecular Markers For Phaseolus Vulgazis

Env gene encodes virus surface glycoprotein.which mostly exists in animal retroviruses and is infectious.In plants,ENV genes are also found in Arabidopsis and soybean,but its specific function is not clear.Legumes are important oil crops and the main source of essential nutrients such as human protein and vitamin.In this study,the published genome of major legumes was used for the first time,and the ENV elements in each genome were comprehensively analyzed by means of bioinformatics,including annotation of elements,classification of family and superfamily,study of evolutionary pedigree,analysis of gene impact and expression analysis,so as to clarify the potential function and origin of ENV gene in legumes.As well as the development of RBIP molecular markers,to make some data support for assisted breeding.The main results of this study are as follows:1、From the published genome of leguminous plants,we selected the genome of common bean,alfalfa,Lotus japonicus,red bean,mung bean,soybean,chickpea,pigeonpea and cowpea with good sequence quality.337,94,25,107,51,1993,15,37 and 102 ENV elements were identified.Among them,the ENV elements of pvr9 family in common bean are 253,and the GM2,Gm6 and gm9 families in soybean are 763.436 and 456,accounting for 75%and 83%of the total ENV elements.The ENV elements in soybean and common bean are mainly distributed in heterochromatin region,and tend to be inserted into GC rich region2、In soybean,conmmon bean,alfalfa and cowpea,116,52,25 and 41 genes were found in the region<2KB near ENV element.These genes are mainly concentrated in cells and organelles in cell components.Molecular functions mainly involve ion binding,transmembrane receptor and catalytic activities of various enzymes.Biological processes mainly involve cell processes and metabolic processes.3、The insertion time,pedigree and expression of ENV were analyzed.Among soybean,1266 were inserted in nearly 500000 years,accounting for 63.5%of the total ENV elements;among cowpea 102 elements,46 were inserted in 0.5 million years(45.1%);among 94 alfalfa ENV LTR-RT elements,86 were inserted in nearly 0.5 million years;among soybean,alfalfa and cowpea elements,the amplification trend was linear upward;among common bean,red bean and green bean,the active period was 1.5-3 million years.Genealogical analysis showed that the ENV elements of the Copia superfamily of all species were mainly concentrated in Maximun genealogy,while the ENV elements in Gypsy were mainly concentrated in Athila and Tat.The phylogenetic tree analysis of env gene showed that in legumes,the env gene in copia element and Gypsy element evolved relatively independently.EST sequence alignment of ENV elements showed that soybean and common bean ENV Itr elements were mainly expressed in roots and seeds,showing tissue-specific expression.4、25 LTR-RT elements with and without ENV were randomly selected to design primers.17 pairs of core primers were screened out from 36 accessions of Phaseolus vulgaris by PCR.Among them,3 and 14 polymorphic primers were selected for selfcontained ENV and non-contained ENV Itr-rt elements,respectively.These 17 pairs of polymorphic primers completely distinguished 36 accessions of Phaseolus vulgaris,which were divided into 4 groups in cluster analysis,and constructed the unique molecular identity card of 36 accessions of Phaseolus vulgaris.