The Roles Of GmARF2a Gene In Plant Growth And Development

Soybean(Glycine max [L.] Merr.)is one of the most important grain and oil crops in the world,which provides high quality vegetable protein and oil for human beings.In recent years,China’s soybean demand has increased sharply,while the domestic soybean output has stagnated,and there is a huge demand gap in the market.To further improve soybean yield is of great significance for safe guarding national food security and improving people’s quality of life.Auxin plays an important role in the growth and development of soybean,and auxin response factor(ARF),as a transcription factor,is involved in regulating the response of Auxin.In this study,GmARF2 a gene was overexpressed in soybean composite plants and Arabidopsis thaliana,and the function of GmARF2 a gene was preliminarily verified.The main results are as follows:1.Glyma.19G206100 gene is successfully cloned and named GmARF2 a.The total length of the genome is 11,279 bp,and the ORF is 2034 bp,encoding 677 amino acids.The molecular weight of the protein encoded by the gene is 75.65 k Da,and the isoelectric point Pi is 7.11.Phylogenetic tree analysis shows that GmARF2 a is the most closely related homologous gene to wild soybean(KHN43557.1).Comparison of functional domains between PB1 and B3 shows that the functional domains of GmARF2 a and At ARF2 are similar.Real-time PCR was used to detect the expression of GmARF2 a gene in the root,stem,leaf,flower and shoot tip tissues of Williams 82 variety in soybean.The results showed that the expression of GmARF2 a gene was the highest in flowers,followed by stem tips,roots,stems and leaves.The results of subcellular localization showed that GmARF2 a was expressed in the nucleus and cell membrane.2.Composite plants with overexpression expression of GmARF2 a genes were obtained using soybean hair rooting technology system.After 30 days of rhizobia infection,the phenotypes of nodules and hair roots of the composite plants and the control were analyzed statistically.Results showed that,overexpressing GmARF2 a could make soybean composite plant leaf chlorophyll content increased by 17.2%,leaf nitrogen content increased by 14.3%,hair root length increased by 35.1%,hair root number increased by 69.2%,hair root fresh weight increased by 1.1 times,number of nodules increased by 1.6 times,nodule weight increased by 1.5 times,and tumors had increased 1.6 times.3.The soybean GmARF2a gene was overexpressed in Arabidopsis thaliana Col-0to obtain the T3 transgenic lines.The germination rate,flowering time,plant height,number of fruit pods and length of fruit pods were investigated with wild type as control.The results showed that,compared with the wild type,the over-expression of GmARF2 a could reduce the germination rate by 14.8%,delay the flowering time by 7days,increase the plant height by 36.4%,increase the number of fruit pods by 53.1%,and increase the length of fruit pods by 26.3%,the content of IAA was determined by liquid chromatography,and the content of IAA increased by 33.3%.Transcriptome sequencing analysis of GmARF2 a overexpressed strains and wild type showed that634 differentially expressed genes were up-regulated and 863 differentially expressed genes were down-regulated,among which 11 differentially expressed genes were directly related to auxin signal transduction pathway.GmARF2 a up-regulated genes were At CYP71A12,At CYP71A13,At PBS3,At SAUR29,At CYP79B2,AT1G56150,AT2G16580,AT3G12830.GmARF2 a down-regulated genes were At WES1,At IAA31,AT2G46690.