Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/30/2005
Publication Date: N/A
Technical Abstract: Perennial ryegrass (Lolium perenne L.) and Italian (or annual) ryegrass (L. multiflorum Lam.) are two of the most widely cultivated grasses used for turf and forage throughout the world. Identifying annual ryegrass contamination in perennial ryegrass seed lots has been of major interest in the seed industry for many years. An interspecific, three-generation genetic mapping population (MF population) was developed between annual and perennial ryegrass and was used to genetically map other traits which can be used to differentiate the two species (Warnke et al., 2002; 2004). As part of a project to develop molecular markers for distinguishing the two species, we are mapping a homolog (LpCO) of the CONSTANS gene from Arabidopsis, AtCO. AtCO belongs to a family of putative transcription factors defined by two conserved domains, a zinc finger, and a CCT (CO, CO-like and TOC1) domain. Related CONSTANS-like homologs ZCCT-1 and HvZCCT have been identified in winter wheat and barley that play a central role in the vernalization response required for flowering (Yan et al., 2004; Karsai et al., 2005; Dubcovsky et al., 2005). PCR Primers were designed to amplify the single intron in LpCO, based on the full-length cDNA sequence (GenBank # AY600919). This region was cloned and sequenced from the parents of the MF mapping population and a SNP was identified and is being used as the basis for mapping LpCO in the population. The position of LpCO will be compared to vernalization-responsive QTLs that have been identified in the MF population. By combining the genetic linkage mapping and the QTL analysis, we will determine if LpCO is a candidate for the vernalization response gene. At the same time, we will clone and sequence LpCO in a panel of annual and perennial genotypes to identify sequence polymorphisms that may be linked to the growth habit.