The Preliminary Analysis Of The Function Of Small Heat Shock Protei Genes CmsHsp1/6/28 And Heat Shock Transcriptiont Factor Gene CmHsf18 In Fruit Development Of Melon

Melon（Cucumis melo L.）is an annual herb belonging to Cucumis of Cucurbiteace.In this study,three small heat shock protein genes（CmsHsp1/6/28）and one heat shock transcription factor gene（CmHsf18）were obtained from the transcriptome data of melon fruits completed in our laboratory.CmsHsp1/28 and CmHsf18 were highly expressed in respiratory climacteric stage（C stage）and post climacteric stage（P stage）,and CmsHsp6 was highly expressed in growth stage（G stage）.Bioinformatics and expression profile analysis,cDNA cloning,construction of super expression vector and genome editing vector,and genetic transformation analysis were carried out for the four candidate genes.The main results are as follows:（1）Through bioinformatics analysis,33 members of small heat shock protein（CmsHsp）family and 23 members of heat shock transcription factor family（CmHsf）were identified from the whole genome of melon.The promoters of four genes contain a variety of plant hormone response elements,of which four genes contain abscisic acid and ethylene response elements,and the promoters of CmsHsp1 and CmsHsp28 genes contain auxin response elements,CmsHsp1 and CmHsf18 contain gibberellin response elements,and CmsHsp6 contain salicylic acid response elements.CmsHsp1 is on chromosome 0,CmsHsp6 is on chromosome 4,CmsHsp28 is on chromosome 10,and CmHsf18 is on chromosome 8.（2）The expression levels of four genes in roots,stems and leaves were significantly lower than those in melon fruits（P-value<0.01）by real-time fluorescence quantitative PCR,the expression of R phase was 10-22 times higher than that of leaves.The expression of CmsHsp1/28 and CmHsf18 was the highest in phase C,and the expression of CmsHsp6 was the highest in phase G,which was consistent with the results of transcriptome sequencing.（3）The cDNA of CmsHsp1/6/28 and CmHsf18 were cloned,and the ORF of them were 477 bp,600 bp,478 bp and 843 bp respectively.（4）A large number of T₁ transformed seeds were obtained by ovary injection.The PCR positive rate was 8.8%-13.3%.T₁ transformed seeds were seeded in sunlight greenhouse.It was found that T₁ melon fruits with overexpression of CmsHsp28 gene ripen 4.4 days later than the control fruit,and the T₁ fruits of transformed with editing vector of CmsHsp28 gene ripen 3.1 days earlier than the control fruit.The above results showed that CmsHsp28 gene had the function of delaying the ripening of melon fruit.