Genetic Analysis Of A Barley Mutant Without Ligule

Plant architecture including plant height, tiller number and angle, leaf shape and angle, represents an important agronomic trait which could significantly effect the grain yield.Therefore, isolation of key genes and understanding of the developmental mechnism of plant architecture are of great importance for designing ideal plant architecture in crop breeding. In this study, we identified one liguleless barley mutant from EMS induced population of cultivated variety "Tamalpais". Phenotypes of liguleless and wild type were segerated with a ration of 1:3 in F2 population, indicating the liguleless was controlled by one recessive gene. Molecular markers were developed based on the homologous LG1 gene of maize, and the results showed they were co-segerated with the liguleless phenotype in more than 400 F2 individuals.We further sequenced the full length LG1 gene of the barley mutant and "Tamalpais" One SNP (Single Nucleotide Polymorphism) was identified in the first exon of barley LG1 homolog gene, and the SNP in barley mutant resulted in amino acid change compared to that of the wild type. These results suggested that this barly mutant was most probably controlled by the conserved LG1 gene. Differently, the liguleless phenotype previsously reported in rice or maize were resulted from nonsense mutantion of LG1, but in this study it was from one missense mutation. Furthermore, expression analysis of HvLGl, found that the gene expressed mainly in the parts of ligule, no differences of the expression level was observed between the barly mutant and the wild type.Therefore we proposed this SNP destroyed the function of the barlye LG1. In addition, there was an insertion of a 3.5 kb DNA transposon in the barley mutant. However, it might not effect the gene function since it was also present in the wild type "Tamalpais". This work is useful for further functional studis of the LG1 gene and the creation of novel germplasms.