The Molecular Marker Study On Sex Differences Of Buchloe Dactyloides

Buffalograss, Buchloe dactyloides (Nutt.) Engelm, represents a monospecific genus in the tribe Chlorideae (Poaceae). It is a dioecious turfgrass native to the Great Plains of North America. Being a low maintenance species, it has become the most widely cultivated warm-season turfgrass in northern China since it was naturalized in this region. While dioecious plants represent only a small proportion of all plant species, they are important models in the study of plant sex determination and evolution. Based on the research of morphology and molecular biology, the objectives in this paper were to use SRAP combined BSA to find sex specific markers in B. dactyloides and two-dimensional electrophoresis (IEF/SDS-PAGE) methods to separate the different proteins at the stage of sex differentiation. The results provide a simple and reproducible means of early sex identification in B. dactyloides, meanwhile provide new evidence for sex differentiation of B. dactyloides. The experiments and the results were listed as following:1) The first objective of this study was to use sequence-related amplified polymorphism (SRAP) and integrated bulked segregant analysis (BSA) technology to find sex linked markers in B. dactyloides. Female and male DNA pool were detected in this study respectively. A total of 228 primer combinations were screened and 207 combinations generated 2690 SRAP bands. Thus 19 pairs of primer combinations were able to amplify divergent bands between female and male DNA pool. Only ME9/EM2 could generate a specific fragment (-240bp) in all the female plants, which was absent in male plants. The methods described here provide a simple and reproducible means of early sex identification in B. dactyloides.2) It was reported the results of comparison of the total protein composition of female and male inflorescences at the development stage of sex differentiation, using two-dimensional electrophoresis (IEF/SDS-PAGE) methods. A total of 18 proteins were differentially expressed at this stage.12 proteins were present at different development stage in female and male floret with different expression value. Then 4 specific proteins appeared before sex determination and disappeared after determination stage. Two specific protein spots, H and N were found out related with female and male floret differentiation. The results suggested that protein H may be an important protein leading contabescence in female floret. And protein N may be a significant protein which leads the abortion of gynoecium in male floret. SRAP molecular makers were used to detect a sex-linked band in female plants,which could be used for sex identification of B. dactyloides. The total protein composition of female and male inflorescences was screened at the development stage of sex differentiation, using two-dimensional electrophoresis methods. Two sex-linked specific proteins were separated. The results clarified mechanism of sex determination of B. dactyloides at molecular level. Considering that B. dactyloides is dioecious plant in family of Poaceae, this paper provide a new material and method for sex differentiation and identification.