Studies for different reproductive strategies in Chenopodiaceae crops

点击翻译按钮获取中文摘要

Sugar beet and spinach, members of Chenopodiaceae, have evolved different strategies to prevent self-fertilization and promote outcrossing. The former has developed cytoplasmic male sterility (CMS) and the latter has evolved dioecism. Molecular mechanisms of the CMS and the dioecism in the crops were analyzed to understand the diversity of reproductive strategies in plants.In sugar beet, Owen CMS-associated pre-SATP6 is a mitochondrial membrane protein that assembles into a homogeneous 200-KDa protein complex. Here we found that the product of a nuclear restorer gene (Rf1) for Owen CMS interacts with preSATP6, resulting in the significant reduction of the 200-KDa protein complex and restoration of pollen fertility. We also identified at least 16 distinct alleles in the Rf1 locus from sugar beet and its close relatives, using a variety of DNA markers. The molecular mechanisms of other sources of CMS and evolution of Rf1 locus are worthy of further investigation.Spinach (Spinacia oleracea) is a dioecious plant. Our study revealed that its wild relatives, S. turkestanica and S. tetrandra, are also dioecious plants with unisexual flowers morphologically quite similar to those of spinach. We identified male specific DNA sequences in spinach, which were also found to be male-specific for all accessions of S. turkestanica and some accessions of S. tetrandra examined. The accessions from the wild species were shown to possess chloroplast intergenic sequences (trnL-rpl32) identical to that of spinach (S. oleracea). However, most accessions of S. tetrandra lack the DNA sequences specific for male spinaches, whose trnL-rpl32 sequences are distinctive from that of spinach. The results suggested that the sex determining locus and sex chromosomes are differentiated among members of genus Spinacia.