tailieunhanh - báo cáo khoa học: " Functional analysis of B and C class floral organ genes in spinach demonstrates their role in sexual dimorphism"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Functional analysis of B and C class floral organ genes in spinach demonstrates their role in sexual dimorphism | Sather et al. BMC Plant Biology 2010 10 46 http 1471-2229 10 46 BMC Plant Biology RESEARCH ARTICLE Open Access Functional analysis of B and C class floral organ genes in spinach demonstrates their role in sexual dimorphism D Noah Sather 1 2 Maja Jovanovic1 and Edward M Golenberg 1 Abstract Background Evolution of unisexual flowers entails one of the most extreme changes in plant development. Cultivated spinach Spinacia oleracea L. is uniquely suited for the study of unisexual flower development as it is dioecious and it achieves unisexually by the absence of organ development rather than by organ abortion or suppression. Male staminate flowers lack fourth whorl primordia and female pistillate flowers lack third whorl primordia. Based on theoretical considerations early inflorescence or floral organ identity genes would likely be directly involved in sex-determination in those species in which organ initiation rather than organ maturation is regulated. In this study we tested the hypothesis that sexual dimorphism occurs through the regulation of B class floral organ gene expression by experimentally knocking down gene expression by viral induced gene silencing. Results Suppression of B class genes in spinach resulted in the expected homeotic transformation of stamens into carpels but also affected the number of perianth parts and the presence of fourth whorl. Phenotypically normal female flowers developed on SpPI-silenced male plants. Suppression of the spinach C class floral organ identity gene SpAG resulted in loss of reproductive organ identity and indeterminate flowers but did not result in additional sex-specific characteristics or structures. Analysis of the genomic sequences of both SpAP3 and SpPI did not reveal any allelic differences between males and females. Conclusion Sexual dimorphism in spinach is not the result of homeotic transformation of established organs but rather is the result of differential initiation and development of