Studies of genes potentially involved in the induction of flowering in Festuca pratensis (Huds.)

Abstract

Many plants in northern regions require a period of low temperatures and short days (called vernalisation) during the winter season to initiate the flowering process. In this experiment, some genes thought to be involved in vernalisation response and induction of flowering in meadow fescue (Festuca pratensis) has been investigated. The genes were chosen based on their possible contribution in the transition from vegetative to reproductive phase in cereals. The investigations were predominantly gene expression studies on vernalised and non-vernalised plant material from genotypes that are able to flower without vernalisation and genotypes with vernalisation requirement. These experiments were done using RT-PCR with cDNA from the different plant genotypes as templates. VRN1, a positive regulator of flowering in cereals, was up regulated by vernalisation in F. pratensis. The results also showed a connection between VRN1 expression and vernalisation requirement. Genotypic differences have been identified in the VRN1 promoter or intron 1 in cereals with differences in vernalisation requirement. These areas are suggested to contain binding sites for repressors of VRN1. The first 1kb of F. pratensis VRN1 intron 1 was sequenced and shown to be identical in the two parents of our mapping population (with different vernalisation requirement). The expression of the putative flowering repressor, MADS16, seemed to be down regulated by vernalisation in the plants that required vernalisation to flower. The plants that were able to flower without vernalisation had a MADS16 expression un-affected by vernalisation. Some investigations were also done on VRN2 (a putative repressor of VRN1 expression), PHYC (a photoreceptor), RUBQ2 (ubiquitin) and CONSTANS (a positive regulator of flowering in Arabidopsis).