S.cn (Y.Y.) Institute of Plant Protection, Sichuan Academy of
S.cn (Y.Y.) Institute of Plant Protection, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China; [email protected] Correspondence: [email protected] (X.Z.); [email protected] (Y.L.); Tel.: +86-028-84590090 (X.Z.); +86-0571-63370333 (Y.L.) The very first two authors contributed equally to this function.Citation: Tang, W.; Liu, S.; Yu, X.; Yang, Y.; Zhou, X.; Lu, Y. The Basis of Tolerance Mechanism to Metsulfuron-Methyl in Roegneria kamoji (Triticeae: Poaceae). Plants 2021, ten, 1823. doi/ ten.3390/plants10091823 Academic Editor: Simon Hodge Received: 3 August 2021 Accepted: 29 August 2021 Published: 1 SeptemberAbstract: Roegneria kamoji, a perennial monocot weed that belongs towards the tribe Triticeae (family: Poaceae), is an emerging problematic weed in winter wheat (Triticum aestivum) ADC Linker Storage & Stability fields in China. We have previously confirmed four R. kamoji populations tolerant to acetyl-CoA carboxylase (ACCase) inhibitors, and Failed manage of those populations by metsulfuron-methyl was observed. The objective of this study was to characterize the level of tolerance to metsulfuron-methyl, the basis of tolerance mechanism, and cross-tolerance to acetolactate synthase (ALS) inhibitors in R. kamoji. A whole-plant dose esponse assay showed that plants of all R. kamoji populations (both from wheat fields and uncultivated locations) exhibited high tolerance to metsulfuron-methyl, according to their one hundred survival at 6-fold suggested field dose (RFD) and ED50 values six.84-fold RFD, no susceptible population was located. Gene sequencing indicated that no reported amino acid substitutions related with resistance to ALS inhibitor were found within the ALS gene amongst the R. kamoji populations. Pretreatment together with the identified cytochrome P450 monooxygenases (CytP450) inhibitor malathion lowered the ED50 values of metsulfuron-methyl in two R. kamoji populations. These populations also exhibited crosstolerance to RFD of mesosulfuron-methyl and bispyribac-sodium. The activities of glutathione-Stransferase (GST) and CytP450 may be induced by metsulfuron-methyl in R. kamoji, that is equivalent to the recognized tolerant crop wheat. This really is the initial report elucidating metsulfuron-methyl tolerance in R. kamoji. The reversal of tolerance by malathion plus the GST and/or CytP450 enhanced herbicide metabolism suggests that non-target-site mechanisms confer tolerance to metsulfuron-methyl in R. kamoji. Keyword phrases: prevalent Roegneria; ALS inhibitor; non-target website; cytochrome P450; glutathione S-transferasesPublisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional PI3Kδ manufacturer affiliations.1. Introduction Roegneria kamoji is actually a frequent perennial weed that belongs to Roegneria of the tribe Triticeae (Poaceae loved ones). It can be widely distributed across China, Korea, and Japan, and is normally located in hillside, grassland, urban green spaces, and field borders [1,2]. In recent years, R. kamoji has been found spreading in winter wheat (Triticum aestivum) fields in Hubei, Anhui, and Zhejiang provinces of China (Supplemental Figure S1), and has turn into a dominant weed in some regions [3,4]. It has been the practice of lots of farmers to utilize acetyl-CoA carboxylases (EC 6.four.1.2, ACCase) inhibitors, like fenoxaprop-ethyl, clodinafop-propargyl, and pinoxaden for postemergence handle of graminaceous weeds in wheat [5,6]. Failed manage of R. kamoji by fenoxaprop-ethyl was observed in each populations collected from wheat fields and uncultivated places, which implies ther.