College of Plant Protection, Shandong Agricultural University, Tai'an 271018, Shandong, China; Key Laboratory of Pesticide Toxicology and Application Technology, Shandong Agricultural University, Tai'an 271018, Shandong, China.
Administration Bureau of the Yellow River Delta National Nature Reserve, Dongying 257091, Shandong, China.
Pestic Biochem Physiol. 2019 Jul;158:12-17. doi: 10.1016/j.pestbp.2019.04.001. Epub 2019 Apr 1.
Lithospermum arvense is a troublesome dicotyledonous winter annual weed of wheat in China. A L. arvense population (HN01) suspected of being resistant to acetolactate synthase (ALS) inhibitors was found in Henan Province, China. This study aimed to testify the sensitivity of this HN01 population to eight herbicides from 3 different modes of action, and to explore the potential target-site-resistance mechanism to tribenuron-methyl. The whole-plant bioassays indicated that the population was highly resistant to tribenuron-methyl (SU, 350-fold), pyrithiobac sodium (PTB, 151-fold), pyroxsulam (TP, 62.7-fold), florasulam (TP, 80.6-fold), and imazethapyr (IMI, 136-fold), but was sensitive to carfentrazone-ethyl and fluroxypyr-meptyl. ALS gene sequencing revealed that the Trp (TGG) was substituted by Leu (TTG) at codon 574 in resistant plants. In in vitro ALS assays, the concentration of tribenuron-methyl required to inhibit 50% ALS activity (I) for HN01 was 117-fold greater than that required to inhibit a susceptible population (HN05), indicating that resistance was due to reduced sensitivity of the ALS enzyme to tribenuron-methyl. To the best of our knowledge, this is the first report of ALS gene Trp-574-Leu amino acid mutation confer resistance to tribenuron-methyl in L. arvense.
田旋花是中国小麦田中的一种阔叶型一年生杂草。在中国河南省发现了一个疑似对乙酰乳酸合成酶（ALS）抑制剂具有抗性的田旋花种群（HN01）。本研究旨在验证该 HN01 种群对 8 种来自 3 种不同作用模式的除草剂的敏感性，并探索其对三氟啶磺隆的潜在靶标抗性机制。全株生物测定表明，该种群对三氟啶磺隆（SU，350 倍）、吡唑草胺（PTB，151 倍）、砜嘧磺隆（TP，62.7 倍）、氟唑磺隆（TP，80.6 倍）和咪唑乙烟酸（IMI，136 倍）高度抗性，但对甲羧氟草醚和氟吡甲禾灵敏感。ALS 基因测序显示，抗性植株中第 574 位密码子的色氨酸（TGG）被亮氨酸（TTG）取代。在体外 ALS 测定中，HN01 抑制 50%ALS 活性（I）所需的三氟啶磺隆浓度比敏感种群（HN05）高 117 倍，表明抗性是由于 ALS 酶对三氟啶磺隆的敏感性降低所致。据我们所知，这是首例报道田旋花 ALS 基因 Trp-574-Leu 氨基酸突变导致对三氟啶磺隆的抗性。
