Functional Verification Of EjBZR1 And Related Genes Regulating The Growth Of Loquat Fruit

Loquat(Eriobotrya japonica Lindl.)is native to China and neighboring countries and is an evergreen plant of the family Rosaceae.Different from the habits of other Rosaceae fruit trees,"Spring blossoming,autumn fruiting",the cultivated loquat has the unique flowering characteristics of "autumn winter blossoming,spring and summer fruiting".The fruit is listed in the late spring and early summer to fill the seasonal fresh fruit,and its fruit is succulent and rich in many kinds of biologically active substances,making it popular in the market.At present,there are many bottlenecks in the production of hazelnut products because the fruit is too small to be widely promoted.It is imperative to study the regulation of fruit growth to obtain the ideal size of the fruit.The paraffin section analysis of the fruits of nine species of Brassica in the early stage of the research group found that the cell size had a greater influence on the fruit size than the number of cells.Cell size is regulated by a variety of environmental factors and hormonal signals,of which brassinolide(BR)and auxin have the greatest impact,and BZR1 and related genes can be linked to regulate cell size.In the BR signaling pathway,Arabidopsis P450 and BES genes have been reported.CYP90A1-CPD can regulate CYP85A1/A2,affecting BR biosynthesis,BZR1,BZR1/BES1 can accept BR signal feedback regulation,and regulate downstream gene regulation size.In addition to the transcription factors in the BR signaling pathway,a class of b HLH transcription factors have also been found to be involved and involved in the regulation of downstream auxin signaling.In this study,two fruit-sized and extremely different strains(The big fruit of ZP65 and The small fruit of ZP44)in the’Zhaozhong-6’×’Pelluches’hybrid population were used as experimental materials to observe the cell development in different growth stages by paraffin section.The cell differences were compared.The homologous genes of Ej BZR1 and its related genes were cloned and sequenced by using the mixed c DNA of fruits in multiple periods as a template.The expression pattern of the fruit in different stages of the fruit was analyzed by q PCR technique.At the same time,Arabidopsis thaliana was transformed,and the genetic function of Ej BZR1 and its related genes was verified by VIGS treatment in the middle and late stages of fruit development of’Zhaozhong-6’.The main findings of the study are as follows:(1)Observing the fruit development of two fruit-sized and extremely different strains(The big fruit of ZP65 and The small fruit of ZP44)in the’Zhaozhong-6’×’Pelluches’hybrid population,and sampling and making paraffin sections for sampling Dynamic observation of cell size changes showed that the cell size of the two cells showed significant differences at 42 days after flowering,and the difference was sharply increased at 42-84 days after flowering,causing a significant difference in the final size of the fruit.(2)Using the homologous gene to query in the枇杷database,the sequence encoding Ej BZR1 and related genes was obtained,and the target gene was cloned from the mixed samples of fruits in multiple periods.The amino acid sequence alignment indicated that Ej BZR1 and related genes have high homology with homologous genes of other species,and important amino acid functional sites are conserved.Phylogenetic tree analysis indicated that both Ej BZR1 and related genes have conserved domains.(3)The fruits of ZP65 and ZP44 at different times were used as materials,and the time-space expression pattern of genes was analyzed by q PCR technique.The results showed that the expression patterns of Ej CYP90A1,Ej CYP85As and EjbHLH137-1/137-2 overlap with the fruit cell expansion pattern,and the expression level of the gene in both materials is positively correlated with cell size,while the expression pattern of Ej BZR1/Ej BEH4 is opposite,suggesting Ej BZR1 and Its related genes are important transcription factors that regulate fruit size.(4)VIGS treatment of different target genes in the early and late fruit development of’Zhaozhong-6’showed that the expression levels of Ej CYP90A1 and Ej CYP85As.EjbHLH137s were significantly lower in the treated fruits than in the control fruits,and the cell size and final fruit size after VIGS treatment were all Significantly smaller than the control group.Ej BZR1/BEH4 is just the opposite.These experimental results demonstrate that Ej BZR1 and its related genes are linked to each other to regulate fruit size.(5)Ej BZR1 and its related genes were transformed into Arabidopsis thaliana.The results showed that the leaves of Ej BZR1/BEH4 were significantly smaller than the wild type,and the convulsions were obviously later than the wild type,while other target genes were opposite.