HvFT1 polymorphism and effect - survey of barley germplasm and expression analysis.

Abstract

Flowering time in plants is a tightly regulated process. In barley (Hordeum vulgare L.), HvFT1, homolog of FLOWERING LOCUS T, is the main integrator of the photoperiod and vernalization signals leading to the transition from vegetative to reproductive state of the plant. This gene presents sequence polymorphisms affecting flowering time in the first intron and in the promoter. Recently, copy number variation (CNV) has been described for this gene. An allele with more than one copy was linked to higher gene expression, earlier flowering, and an overriding effect of the vernalization mechanism. This study aims at i) surveying the distribution of HvFT1 polymorphisms across barley germplasm and ii) confirming whether CNV is related to phenotype. We analyzed HvFT1 CNV in 108 winter, spring and facultative barley varieties. There was more than one copy of the gene (2–5) only in spring or facultative barleys, i.e., without a functional vernalization VrnH2 allele. CNV was investigated in several regions inside and around HvFT1. Two models of the gene were found: one with the same number of promoters and transcribed regions. This last model was found in Nordic barleys only.