LAUSR

BACKGROUND Haloxyfop-P-methyl, an acetyl-CoA carboxylase(ACCase)-inhibiting herbicide, has been widely used to control grass weeds. Extensive haloxyfop-P-methyl use has led to glutathione transferase (GST)-mediated resistance in Digitaria sanguinalis in China's cotton fields. In a previous study involving haloxyfop-P-methyl resistant D. sanguinalis, a GST was identified as a candidate resistance gene. In this study, this gene was isolated from young leaf tissue and was identified with amplification analysis combined with sequence analysis, and then its function was validated by heterologous expression in rice. RESULTS A tau class glutathione transferase was identified from D. sanguinalis, designated as DsGSTU1. The full-length coding DNA sequence (CDS) of DsGSTU1 is 717 bp long. Higher expression of DsGSTU1 was observed in haloxyfop-P-methyl-resistant (HR) D. sanguinalis than in haloxyfop-P-methyl-susceptible (HS) plants. Overexpression of the DsGSTU1 gene was verified by transformation into wild-type Nipponbare rice with the recombinant expression vector pBWA(V)HS. GST activity in transgenic rice seedlings was 1.18 to 1.40 times higher relative to wild-type rice seedlings before and after haloxyfop-P-methyl treatment, respectively, and rice seedlings overexpressing DsGSTU1 were less sensitive to haloxyfop-P-methyl. CONCLUSION DsGSTU1 is the first gene related to resistance identified in D. sanguinalis. Our present findings suggest that DsGSTU1 plays a significant role in haloxyfop-P-methyl resistance in D. sanguinali. This herbicide resistance gene could facilitate GST-mediated resistance management and the development of herbicide-resistant crops. This article is protected by copyright. All rights reserved.