Cloning And Preliminary Functional Identification Of Melon CmHsp70-9 And CmXTH28-2 Genes In Fruit Development

Melon?Cucumis melo L.?is a widely cultivated horticultural crop with high economic value.Its storage and transportation have become an important factor affecting economic value.Heat shock proteins?HSPs?,as a molecular chaperone,have important biological functions such as anti-stress,anti-oxidation and regulating apoptosis.Xyloglucan endotransglucosylase?XTH?belongs to cell wall relaxase,which plays an important role in cell wall remodeling during fruit ripening.In this study,Cucumis melo L.cv Hetao,a melon cultivar,was used as the research material.The transcriptome data of melon fruits completed earlier in our laboratory were analyzed.One gene CmHsp70-9 and CmXTH28-2,which were significantly differentially expressed during fruit development,were selected from the above two gene families.Bioinformatics characteristics were analyzed,and two genes were analyzed in different tissues and tissues of melon.Cloning of its cDNA sequence,and the superexpression vector and gene editing vector were constructed respectively.The melon was genetically transformed and the T₁ fruit was phenotypically identified.The following main results were obtained:1.Bioinformatics identified 10 members of Hsp70 and 3 members of XTH family of IIIB subclass.Through analysis,it was found that the members of the two genes were relatively conservative in structure and evolution.2.The expression profiles showed that CmHsp70-9 and CmXTH28-2 were both expressed in fruits.The highest expression was in the late stage of respiratory climacteric and the lowest expression was in the growth stage,and both expressed in rhizome and leaf.3.CmHsp70-9 and CmXTH28-2 were cloned by RT-PCR,and their length were2131 bp and 1190 bp,respectively.4.Genetically transformed melon seeds were obtained by CmHsp70-9 and CmXTH28-2 gene superexpression vectors pPHsp70,pPXTH28 and gene editing vectors pYL-Hsp70 and pYL-XTH28.The positive rates of transformed plants detected by PCR were pPHsp70:14.28%,pYL-Hsp70:8.33%,pPXTH28:17.85%and pYL-XTH28:13.09%.The observation on the ripening stage of T₁ fruits showed that the average ripening period of control fruits was 46 days,11 transformed fruits with superexpression vector T₁ of pPHsp70 were obtained,the average ripening period was 43 days,which was 3 days earlier than that of control fruits,and 11 transformed fruits with late ripening phenotype were obtained with editing vector of pYL-Hsp70,whose ripening period was 55 days and 9 days later than that of control fruits.Nine transformed fruits of CmXTH28 superexpression vector T₁ were obtained.The average maturity period was 41 days,which was 5 days earlier than the control.In conclusion,the preliminary results showed that both CmHsp70 and CmXTH28 genes could promote fruit ripening.