| Crape myrtle(Lagerstroemia indica)belongs to the family Lythraceae,which is regarded as a vital woody flower in summer in China for its beautiful shape,bright-colored flower,long-last bloom period.Nowadays,Crape myrtle always appears as border plants,whose forms of application is simple.The crape myrtle cultivars who have good characteristics with many branches and dwarf architecture are seldom.The genetic rule and regulatory mechanism of shoot branching in crape myrtle are unknown,thus,the study wants to lay a foundation to analyze the genetic discipline and regulation mechanism of shoot branching totally,and put a reference to breeding variety of shoot branching characters in Lagerstroemia indica.The study used L.fauriei,L.indica Pocomoke ' and their hybrid generation F1,BC1,BC2 hybrids,analyzed their characteristics of shoot branching,explored the rule of genetic variation.At the same time,used the technology of RT-PCR/qRT-PCR to isolate genes related to shoot branching and studied specificity of expression in tissues.The functions of gene were studied by transformed into wild-type Arabidopsis using the method of flower organ infection.The main results are listed as follows.(1)Compared with parents,the number of primary shoot branching had higher variation,whose value of CV are 58.16-64.79%.The angle of primary shoot branching had lower variation in progenies,whose value of CV are 25.99-37.71%.The diameter of shoot branching,the number of shoot branching and the angle of shoot branching were important to character of shoot branching in F1,BC1 and BC2 populations.All characters of shoot branching had significant correlations with others.The correlation betAveen characters were not totally the same in different progenies.The characters of shoot branching had significant mid-parent heterosis,no significant heterobeltiosis in progenies.(2)According to the transcriptome data from our research group,and the result of phenotype analysis of shoot branching traits,picked four genes who were involved with shoot branching from differential expression genes in individuals whose number of shoot branching were significant difference.Cloned and obtained the full length of four genes(LagYUC6,LagGH3,LagILL6,LagD14).Four genes included their own open reading frames and oonservative domain.Predicted the proteins they eneoded had high heat stability.The phylogenetic tree suggested crape myrtle had close relative of pomegranate.They had different expression in root,stem,leaf in parents and Fi(5 and D individuals).Compared with L.fauriei and F1(S individuals),LagYUC6 had lower expression,LagGH3 and LagDN had higher expression in relevant tissues of L.indica 'Pocomoke' and F1(D individuals).(3)LagGH3 had the highest expression in four genes from transcriptome data,so constructed the plant expression vector of LagGH3,and obtained the transgenosis Arabidopsis thaliana T2 plant of LagGH3.Compared with WT Arabidopsis thaliana in the saoe time,the transgenosis LagGH3 plants had more number of branches.LagGH3 may affect the number of branches.The results laid a foundation to validate the function of LagGH3.(4)Developed two SSR markers inside of gene in crape myrtle.The two SSR markers and the six markers developed from transcriptome data showed polymorphism in parents and progenies,the value of PIC were low to medium.Eight SSR markers had low accuracy rate in validating phenotype in parents and progenies.The accuracy rate of INYUC1 was 64.29%,the accuracy rate of INYUC2 was 69.44%.In this study,the characters of shoot branching of parents and progenies in crape myrtle were measured,and the genes were isolated and the function was verificated.The SSR markers were developed inside the gene.The results contributed to analyzing the characters and regulatory mechanism of shoot branching and MAS breeding in crape myrtle. |
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