A novel EcGH3 gene with a different expression pattern in quinclorac-resistant and susceptible barnyardgrass (Echinochloa crus-galli)

Some plant GH3 genes are specifically induced by auxin within minutes and play important roles in plant growth and development. A GH3 cDNA was isolated from barnyardgrass. The gene, designated EcGH3.1 (Genebank Number: JN241678), has a full-length 1839 bp open reading frame predicted to encode a 67.82 kDa protein. Sequence alignment showed that EcGH3.1 is a GH3 homolog. Its transcript level in leaves and roots of quinclorac-susceptible (S) biotypes was higher than that in quinclorac-resistant (R) biotypes. After exposure to quinclorac in 30 min, EcGH3.1 expression was obviously decreased in leaves of S biotypes, but markedly increased in leaves of the R plants. EcGH3.1 with its different expression patterns can be considered a marker and applied to distinguish R and S biotypes. The results of this study also provide basic information for further research of the function of EcGH3 in barnyardgrass under herbicide stress.