Study On The Endangered Mechanism And Bioinformatics Mining Identification Of GA Related Genes In Lepisanthes Unilocularis

Lepisanthes unilocularis is an evergreen shrub of Lepisanthes in Sapindaceae family.It is a national level III key protected wild plant and an endemic extinct(Ex)plant in Hainan.After 80 years of discovery,many physiological characters and molecular mechanism of Lepisanthes unilocularis are still unclear.In order to study and try to solve the endangered mechanism,the existing research results show that the most difficult problem is sexual reproduction.There are few male flowers,female flowers and male flowers do not meet in florescence.The seeds are easily dehydrated and inactivated,and the natural germination rate is very low,all kinds of factors lead to the endangered situation of Lepisanthes unilocularis.In order to study the endangered mechanism,the following results were obtained through experiments:(1)The purpose of this experiment is to explore the needs of the growth and development of Lepisanthes unilocularis and its relationship with environmental factors.The fresh weight(WF),total weight(WT),dry weight(WD),leaf area(LA),leaf water content(LWC),leaf relative water content(LRWC),specific leaf weight(SLW),leaf nitrogen content(LNC)and leaf phosphorus content(LPC)of new leaf(NL)and old leaf(OL)were measured.The results showed that LWC(60.21%)of NL was significantly higher than ol(52.17%);WD(0.037g)and SLW(0.013g)of NL were significantly lower than ol(0.046 g and 0.017g).WD,LWC,SLW and LPC have important effects on the growth and development of Lepisanthes unilocularis leaves.(2)In this study,k-mer method was used to estimate the genome size of Lepisanthes unilocularis,and jelyfish was used to process the 141 G sequence data.The length of k = 21 was counted.According to its distribution,the genome size of Lepisanthes unilocularis was about 880.13 mb,the non repetitive sequence was 47.5%,and the heterozygosity was about 0.388%.The results of flow cytometry showed that the plant was diploid and its genome size was about 921.11 mb.(3)GA way is one of the seven ways of flower formation.The content of GA in the root was measured in three stages: normal growth stage,flowering stage and late flowering stage.It was found that the content of GA in the root increased greatly in the flowering stage(0.063?g/g;0.253?g/g;0.736 ?g/g);it decreased significantly in the leaf(3.141?g/g;0.252?g/g;0.154 ?g/g);there was no significant change in the stem(0.430?g/g;0.317?g/g;0.367?g/g).The content of endogenous ABA in roots(0.120?g/g;0.498?g/g;0.944?g/g)and stems(0.347?g/g;0.607?g/g;1.156?g/g)increased significantly,while in leaves(2.524?g/g;1.539?g/g;1.365?g/g).The content of IAA in roots(0.126?g/g;0.134?g/g;0.060?g/g)and leaves(0.618?g/g;0.081?g/g;0.101?g/g)decreased,and in stems(0.208?g/g;0.421?g/g;0.042?g/g)increased first and then decreased.GA pathway is one of the six major flower forming pathways,and endogenous GA is an important factor affecting the flower forming.The researchers chose to start with the identification of the key enzyme genes of GA synthesis,trying to understand the molecular mechanism of the endangered mechanism of Lepisanthes unilocularis.(4)In this study,the gene family of GA2 ox,GA3ox and GA20 ox,the key enzymes of Arabidopsis gibberellin biosynthesis,was mined and identified in the genomic data.The results of protein domain identification showed that GA2 ox,GA3ox and GA20 ox had the same two domains: DIOX_N and 2OG-Fell_Oxy.Six possible GA2 ox genes,four GA3 ox genes and five GA20 ox genes were identified.The differential expression of these genes in different parts of Lepisanthes unilocularis,especially in flowers,may be a key factor affecting the flower formation of Lepisanthes unilocularis.In this study,through the methods of measuring leaf functional traits,identifying genome ploidy and size,detecting endogenous GA,mining GA synthetase related genes,it is concluded that the cause of extinction of Lepisanthes unilocularis,it went to extinction.This study provides the idea and molecular basis for finding the mutant gene and solving the endangered mechanism of Lepisanthes unilocularis.