Study On The Function And Evolution Of SCC3 Gene In Hexaploid Kiwifruit (Actinidia Deliciosa)

Whole genome duplication(WGD)to form polyploid species is an important driving force for the speciation and evolution of plants.The formation mechanisms of polyploid plants mainly include unreduced gametes,somatic cell doubling and hybridization.The research on the function of Meiosis related genes and Gene family is helpful to understand the origin of polyploid species.At present,there are few reports on the research of Meiosis genes,especially the typical polyploid species of kiwifruit in China.In this study,the chromosome coagulin SCC3 apomixis gene involved in meiosis was used to verify its function and evolution history in hexaploid Actinidia deliciosa,which will provide scientific bases for clarifying the polyploidy mechanisms of plant speciation.Therefore,on the basis of the genome assembly of the hexaploid A.deliciosa,we screened apomixis genes,and verified the function of SCC3 gene in A.deliciosa through constructing exogenous gene transformation experiments in Arabidopsis thaliana,and then analyzed the evolution history of the SCC3 gene family via methods of gene expansion and contraction and collinearity analysis.The main conclusions are as follows:(1)The genome of hexaploid A.deliciosa was assembled with a size of 3.91 Gb,and the apomixis genes of A.deliciosa were screened,such as SCC3,AGO104,FIE2,NLD,AFB3,SMC2.(2)Results confirmed that the Ad SCC3 gene in hexaploid A.deliciosa involves in meiosis and is an important component of the lectin core complex.Ad SCC3 played key role in the maintenance of chromosome cohesion during meiosis and the correct separation at the later stage.(3)The results of collinearity analysis support that A.deliciosa originated from the genome duplication of Actinidia chinensis,and A.deliciosa may be developed from tetraploid and diploid A.chinensis.The 29 cardinal chromosomes are likely come from early WGD events that result in high homology among chromosome sets.In conclusion,this study analyzed the function and evolution history of the SCC3 apomixis gene in hexaploid A.deliciosa,and results provide bases in revealing the origin and polyploid mechanism of hexaploid A.deliciosa.