Abstract
Sweet summer grass is a problematic weed in the central Queensland region of Australia. This study found glyphosate resistance in two biotypes (R1 and R2) of sweet summer grass. The level of resistance in these biotypes was greater than 8-fold. The glyphosate dose required to reduce dry matter by 50% (GR50) for the resistant populations varied from 1993 to 2100 g ha−1. A novel glyphosate resistance double point mutation in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene was identified for the first time in sweet summer grass. Multiple mutations, including multiple amino acid changes at the glyphosate target site, as well as mutations involving two nucleotide changes at a single amino acid codon, were observed. Both resistant biotypes exhibited a nucleotide change of CAA to ACA in codon 106, which predicts an amino acid change of proline to a threonine (Pro-106-Thr). In addition, the R1 biotype also possessed a mutation at codon 100, where a nucleotide substitution of T for G occurred (GCT to TCT), resulting in a substitution of serine for alanine (Ala-100-Ser). Understanding the molecular mechanism of glyphosate resistance will help to design effective management strategies to control invasive weeds.
Highlights
IntroductionThe problematic weed is found in the tropic and sub-tropic zones of Africa, the Americas, Asia, and some parts of Europe [2,3,4]
Sweet summer grass (SSG) (Moorochloa eruciformis (Sm.) Veldkamp) (synonym = Brachiaria eruciformis (Sm.) Griseb.) is a noxious weed of field crops and fallow areas in Australia (Figure 1), in the sorghum and cotton-growing areas of Queensland and New South Wales [1]
The primary goal motivating the need to characterize herbicide resistance mechanisms is to frame a strategy for the management of herbicide-resistant weeds, which is mostly dependent on molecular mechanisms and the distribution of the resistance mechanism
Summary
The problematic weed is found in the tropic and sub-tropic zones of Africa, the Americas, Asia, and some parts of Europe [2,3,4]. It is a summer dominant weed; this weed is often present in the late phases of winter crops. After harvesting the summer crop, the remnant of weed impedes the emergence of winter crops It forms thick grass mats in the cropped areas, which interfere and cause a significant crop yield loss [5,6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
