Study On Phylogenetic Relationship Of Fagopyrum In West Of Sichuan Based On MatK And RDNA-ITS

The buckwheat,Fagopyrum of polygonaceae,is considered as one kind of coarse cereals and medicinal plants.China is rich in buckwheat resource,which was reported and named all over the world,including twenty three species,two subspecies and three variants. Cytogenetical study has proved that Fagopyrum existed with both diploid and tetraploid. China especially in southwest is one of the origin of buckwheat,but the research on buckwheat starts late and lacks of investment. The basis research,such as the evolution and the classification of buckwheat is significantly blank;phylogenetic relationship among the species in fagopyrum is undefined,so systematic research is extremely urgent.The classification and relationship of Fagopyrum have been existing controversy.In this study,phylogenetic investigation of thirteen representative buckwheat species which came from southwestern of China has been conducted based on matK gene and ITS sequence,compared with the typoiology classification and cytological analysis.The main results were as follows:1.The matK sequence analysis indicated that:(1)The bootstrap support of the five leading branches reached 99%.(2)The result of all data analysis showed that Fagopyrum pugense was the evolving species of wild buckwheat. Overviewing the evolutionary relationship of all of Fagopyrum, Fagopyrum pugense was situated in cultivated buckwheat and wild buckwheat,and it may be the intermediate form of the two.(3)With relatively far genetic relationship between F.gracilipes var.odontopterum W and F.gracilipes var.odontopterum R,which had their own independent revolution line,F.gracilipes var.odontopterum W may be one of the subspecies of F.gracilipes (Hemsl.) Dam.et Diels while F.gracilipes var.odontopterum R may be the cryptice that indepent from F.gracilipes (Hemsl.) Dam. et Diels.2.The ITS sequence analysis indicated that:(1)different clonings did not always cluster together within a species,which reflected that the ITS sequence of the fagopyrum had distinct genetic differentiation.The factor leading great differentiation may be the wide distribution of Fagopyrum,abandent species groups,or the ploidy change of chromosome.(2) The results of the molecular classification and cytological research showed the close relationship between F.wenchuanense and F.cymosum X,so we speculated that the F.wenchuanense may be a geographic subspecies of the F.cymosum.3.According to DNA barcode,the buckwheat could be divided into two groups:Cluster I contained cultivated species,F.cymosum and its related species; Clusterâ…¡contained wild species,F.qiangcai,F.pugense,F.lineare,F.gracilipes and F.crispatifolium,etc.4.The results of matK and ITS sequence analysis suggested that F.cymosum had much closer genetic relationship with F.tartaricum.An transitional species,which might be Fpugense from this study,could exist between F.tartaricum and wild buckwheats.5.The results of morphology, cytology and molecular level studies had all shown that the distinct difference between F.gracilipes var.odontopterum W and F.gracilipes var.odontopterum R,therefore,they should be two separate sepecies and should be renamed.