Corn poppy (Papaver rhoeas) cross-resistance to ALS-inhibiting herbicides

BACKGROUND: Papaver rhoeas (L.) has evolved resistance to tribenuron in winter wheat fields in northern Greece owing to multiple Pro₁₉₇ substitutions. Therefore, the cross‐resistance pattern to other sulfonylurea and non‐sulfonylurea ALS‐inhibiting herbicides of the tribenuron resistant (R) and susceptible (S) corn poppy populations was studied by using whole‐plant trials and in vitro ALS catalytic activity assays. RESULTS: The whole‐plant trials revealed that tribenuron R populations were also cross‐resistant to sulfonylureas mesosulfuron + iodosulfuron, chlorsulfuron and triasulfuron. The whole‐plant resistance factors (RFs) calculated for pyrithiobac, imazamox and florasulam ranged from 12.4 to > 88, from 1.5 to 28.3 and from 5.6 to 25.4, respectively, and were lower than the respective tribenuron RF values (137 to > 2400). The ALS activity assay showed higher resistance of the ALS enzyme to sulfonylurea herbicides (tribenuron > chlorsulfuron) and lower resistance to non‐sulfonylurea ALS‐inhibiting herbicides (pyrithiobac > florasulam ≈ imazamox). CONCLUSION: These findings indicate that Pro₁₉₇ substitution by Ala, Ser, Arg or Thr in corn poppy results in a less sensitive ALS enzyme to sulfonylurea herbicides than to other ALS‐inhibiting herbicides. The continued use of sulfonylurea herbicides led to cross‐resistance to all ALS‐inhibiting herbicides, making their use impossible in corn poppy resistance management programmes. Copyright © 2011 Society of Chemical Industry     

Mutations of the ALS gene endowing resistance to ALS-inhibiting herbicides in Lolium rigidum populations

BACKGROUND: In the important grass weed Lolium rigidum (Gaud.), resistance to ALS‐inhibiting herbicides has evolved widely in Australia. The authors have previously characterised the biochemical basis of ALS herbicide resistance in a number of L. rigidum biotypes and established that resistance can be due to a resistant ALS and/or enhanced herbicide metabolism. The purpose of this study was to identify specific resistance‐endowing ALS gene mutation(s) in four resistant populations and to develop PCR‐based molecular markers. RESULTS: Six resistance‐conferring ALS mutations were identified: Pro‐197‐Ala, Pro‐197‐Arg, Pro‐197‐Gln, Pro‐197‐Leu, Pro‐197‐Ser and Trp‐574‐Leu. All six mutations were found in one population (WLR1). Each Pro‐197 mutation conferred resistance to the sulfonylurea (SU) herbicide sulfometuron, whereas the Trp‐574‐Leu mutation conferred resistance to both sulfometuron and the imidazolinone (IMS) herbicide imazapyr. A derived cleaved amplified polymorphic sequences (dCAPS) marker was developed for detecting resistance mutations at Pro‐197. Furthermore, cleaved amplified polymorphic sequences (CAPS) markers were developed for detecting each of the six mutant resistant alleles. Using these markers, the authors revealed diverse ALS‐resistant alleles and genotypes in these populations and related them directly to phenotypic resistance to ALS‐inhibiting herbicides. CONCLUSION: This study established the existence of a diversity of ALS gene mutations endowing resistance in L. rigidum populations: 1–6 different mutations were found within single populations. At field herbicide rates, resistance profiles were determined more by the specific mutation than by whether plants were homo‐ or heterozygous for the mutation. Copyright © 2008 Society of Chemical Industry     

多花水苋对苄嘧磺隆的抗性水平及靶标抗性机制

为明确水稻田杂草多花水苋Ammannia multiflora对乙酰乳酸合成酶 (ALS) 抑制剂类除草剂苄嘧磺隆的抗性水平和抗性分子机制,采用整株水平测定法,测定了采自江苏省扬州市田间的多花水苋疑似抗性种群 (YZ-R) 对苄嘧磺隆的抗性指数,并分析了YZ-R种群和相对敏感种群 (YZ-S)多花水苋ALS酶对苄嘧磺隆的敏感性差异,同时比较了YZ-R和YZ-S种群ALS基因的核苷酸序列差异。结果表明:YZ-R种群多花水苋对苄嘧磺隆已表现出高水平抗性,其抗性指数 (RI) 为40.6;苄嘧磺隆对YZ-R种群ALS酶活性的抑制中浓度 (I₅₀) 为0.087 μmol/L,对YZ-S种群的I₅₀值为0.0028 μmol/L,其抗性指数为31.1。通过PCR扩增获得了多花水苋ALS基因的部分序列,该序列包含了已报道的8个氨基酸突变位点。ALS基因序列比对分析发现,YZ-R种群多花水苋植株ALS基因第197 位氨基酸由脯氨酸 (CCT) 突变为丝氨酸 (TCT)。研究表明,ALS基因发生脯氨酸 (Pro)-197-丝氨酸 (Ser) 的突变,导致多花水苋ALS酶对苄嘧磺隆的敏感性下降,是多花水苋YZ-R种群对苄嘧磺隆产生高水平抗性的主要原因。     

Molecular characterisation of resistance to ALS-inhibiting herbicides in Hordeum leporinum biotypes

BACKGROUND: The acetolactate synthase (ALS)-inhibiting herbicide sulfosulfuron is registered in Australia for the selective control of Hordeum leporinum Link. in wheat crops. This herbicide failed to control H. leporinum on two farms in Western Australia on its first use. This study aimed to determine the level of resistance of three H. leporinum biotypes, identify the biochemical and molecular basis and develop molecular markers for diagnostic analysis of the resistance. RESULTS: Dose-response studies revealed very high level (>340-fold) resistance to the sulfonylurea herbicides sulfosulfuron and sulfometuron. In vitro ALS assays revealed that resistance was due to reduced sensitivity of the ALS enzyme to herbicide inhibition. This altered ALS sensitivity in the resistant biotypes was found to be due to a mutation in the ALS gene resulting in amino acid proline to serine substitution at position 197. In addition, two- to threefold higher ALS activities were consistently found in the resistant biotypes, compared with the known susceptible biotype. Two cleaved amplified polymorphic sequence (CAPS) markers were developed for diagnostic testing of the resistant populations. CONCLUSION: This study established the first documented case of evolved ALS inhibitor resistance in H. leporinum and revealed that the molecular basis of resistance is due to a Pro to Ser mutation in the ALS gene.     

Molecular basis for resistance to tribenuron in shepherd’s purse (Capsella bursa-pastoris (L.) Medik.)

Capsella bursa-pastoris, a winter annual weed in the mustard family, can not be controlled by tribenuron after the herbicide has been continuously used for several years. The resistant biotype Lz-R was the generation of a population collected from Liangzhu, a place where tribenuron had been used for more than 15 consecutive years. To confirm and characterize the resistance of C. bursa-pastoris to tribenuron, whole-plant bioassays were conducted in the greenhouse. The results of whole-plant bioassays revealed that Lz-R was highly resistant to tribenuron with the resistance index (GR₅₀ Lz-R)/(GR₅₀ Lz-S) up to 236.6. To investigate the molecular basis of resistance in C. bursa-pastoris, the acetolactate synthase (ALS) genes were sequenced and compared between susceptible and resistant biotypes. Analysis of the nucleotide and deduced amino acid sequences between the biotypes indicated that one substitution had occurred in Domain A, cytosine by thymine (CCT to TCT) at position 197, that led to a change of the amino acid proline in the susceptible to serine in the Lz-R.     

Cross-resistance of horseweed (Conyza canadensis) populations with three different ALS mutations

BACKGROUND: Horseweed is a weed commonly found in agronomic crops, waste areas and roadsides. Resistance to ALS‐inhibiting herbicides in horseweed was first reported in 1993 in a population from Israel. Resistance to ALS‐inhibiting herbicides in horseweed is now widespread, but, as of now, the resistance mechanism has not been reported. RESULTS: Two of three populations evaluated (P116 and P13) were found to be uniform for resistance (>98% of individuals survived 8.8 g AI ha^?1 of cloransulam), whereas a third population, P525, contained about 85% resistant individuals. Cross‐resistance to cloransulam, chlorimuron, imazethapyr and bispyribac was observed in the P116 population. P525 and P13 were both sensitive to imazethapyr but resistant to chlorimuron, imazethapyr and bispyribac. Enzyme activity assays indicated that resistance in P13 was due to an altered target site. Southern blot analysis indicated that the ALS target site is encoded by a single copy gene. Overlapping ALS gene regions were amplified and sequenced from each population. Amino acid substitutions of Ser for Pro at position 197 (P197S) was detected from P13, Ala for Pro (P197A) was identified from P525 and substitution of Glu for Asp (D376E) at position 376 was found in P116. Molecular markers were developed to differentiate between wild‐type and resistant codons at positions 197 and 376 of horseweed ALS. CONCLUSION: Resistance to ALS‐inhibiting herbicides in horseweed is conferred by target‐site mutations that have also been identified in other weed species. Identification of the mutations within horseweed ALS gene sequence enables molecular assays for rapid detection and resistance diagnosis. Copyright © 2011 Society of Chemical Industry     

Sulfonylurea resistance in Stellaria media [L.] Vill.

A sulfonylurea resistant biotype of common chickweed (Stellaria media L. Vill.) was found in a field treated with chlorsulfuron or metsulfuron for eight consecutive years. In pot experiments the biotype was resistant to postemergence treatments with the following acetolactate synthase (ALS) inhibitors: chlorsulfuron, metsulfuron, tribenuron, triasulfuron, rimsulfuron, sulfometuron, flumetsulam and imazapyr. The level of resistance to chlorsulfuron and sulfometuron was higher than to the other sulfonylurea herbicides. Whereas the level of cross resistance to the triazolopyrimidine herbicide, flumetsulam was comparable to that of metsulfuron, that of imazapyr was significantly lower. In contrast to imazapyr the biotype was not resistant to imazethapyr, an other imidazolinone herbicide. ALS in vitro assays revealed that resistance was due to an ALS enzyme that was less sensitive to ALS inhibiting herbicides. Herbicides with different modes of action were equally effective on the susceptible and resistant biotypes.     

Molecular basis of resistance to sulfonylureas in Papaver rhoeas

A Papaver rhoeas population resistant to several acetolactate synthase (ALS) inhibiting herbicides, called 25/98, was found in Catalonia (Northeastern of Spain). This population has an altered form of the enzyme that showed cross-resistance to several herbicides of this group. The highest resistance was found with tribenuron-methyl and sulfometuron-methyl. Studies were conducted to define the molecular basis of this resistance. Two regions of the ALS gene were amplified using degenerated universal primers and sequenced. Population 25/98 contained a single nucleotide substitution in domain A changing Pro₁₉₇ by Ser (using the nomenclature of Arabidopsis thaliana) that confers sulfonylurea resistance. Another change was detected in a region located outside of any conserved domains described to date, but its implication in the resistance remains unclear. We analyze the putative role of the found mutations in relation to the observed resistance using a putative three-dimensional model of the Papaver ALS enzyme.     

河南省多花黑麦草对ACCase和ALS抑制剂的抗性及其靶标基因突变分析

为明确河南省部分地区的多花黑麦草Lolium multiflorum种群对乙酰辅酶A羧化酶（acetylCoA carboxylase,ACCase）和乙酰乳酸合成酶（acetolactate synthase,ALS）抑制剂类除草剂的抗性水平和抗性机理,采用整株生物测定法测定采自新乡市和驻马店市的多花黑麦草种群对ACCase抑制剂类除草剂精噁唑禾草灵、炔草酯、唑啉草酯和ALS抑制剂类除草剂甲基二磺隆、氟唑磺隆、啶磺草胺的抗性水平,并对多花黑麦草ACCase和ALS靶标酶编码基因进行克隆及氨基酸序列比对,分析其靶标抗性机理。结果显示,与多花黑麦草敏感种群HNXX01相比,HNZMD04和HNXX05种群对6种除草剂均产生了抗性,HNZMD04种群对精噁唑禾草灵和啶磺草胺的相对抗性倍数分别为44.65和40.31,对炔草酯和氟唑磺隆的相对抗性倍数分别为11.91和11.93;HNXX05种群对精噁唑禾草灵和氟唑磺隆的相对抗性倍数分别为27.70和25.67。HNZMD04和HNXX05抗性种群的ACCase基因均发生了D2078G突变,2个种群的突变率分别为55%和70%;HNZMD04...     

小麦田看麦娘对甲基二磺隆的抗性水平及分子机制初探

看麦娘是中国长江中下游地区稻茬麦田的主要恶性杂草之一,甲基二磺隆是防治小麦田看麦娘等禾本科杂草的重要除草剂.该研究团队前期在安徽省凤台县小麦田采集到疑似抗性种群看麦娘(AHFT-01),为明确其对甲基二磺隆的抗性发生情况及潜在的抗性机制,采用温室盆栽法在整株水平上测定了该种群对甲基二磺隆及其他乙酰乳酸合成酶(ALS)抑...     

A novel amino acid substitution Ala-122-Tyr in ALS confers high-level and broad resistance across ALS-inhibiting herbicides

BACKGROUND: Wild radish, a problem weed worldwide, is a severe dicotyledonous weed in crops. In Australia, sustained reliance on ALS‐inhibiting herbicides to control this species has led to the evolution of many resistant populations endowed by any of several ALS mutations. The molecular basis of ALS‐inhibiting herbicide resistance in a novel resistant population was studied. RESULTS: ALS gene sequencing revealed a previously unreported substitution of Tyr for Ala at amino acid position 122 in resistant individuals of a wild radish population (WARR30). A purified subpopulation individually homozygous for the Ala‐122‐Tyr mutation was generated and characterised in terms of its response to the different chemical classes of ALS‐inhibiting herbicides. Whole‐plant dose‐response studies showed that the purified subpopulation was highly resistant to chlorsulfuron, metosulam and imazamox, with LD₅₀ or GR₅₀ R/S ratio of > 1024, > 512 and > 137 respectively. The resistance to imazypyr was found to be relatively moderate (but still substantial), with LD₅₀ and GR₅₀ R/S ratios of > 16 and > 7.8 respectively. In vitro ALS activity assays showed that Ala‐122‐Tyr ALS was highly resistant to all tested ALS‐inhibiting herbicides. CONCLUSION: The molecular basis of ALS‐inhibiting herbicide resistance in wild radish population WARR30 was identified to be due to an Ala‐122‐Tyr mutation in the ALS gene. This is the first report of an amino acid substitution at Ala‐122 in the plant ALS that confers high‐level and broad‐spectrum resistance to ALS‐inhibiting herbicides, a remarkable contrast to the known mutation Ala‐122‐Thr endowing resistance to imidazolinone herbicide. Copyright © 2012 Society of Chemical Industry     

山东省冬小麦田猪殃殃抗药性水平及ASL靶标抗性机理分析

为明确山东省冬小麦田猪殃殃Galium aparine对常规除草剂氯氟吡氧乙酸、苯磺隆及双氟磺草胺的抗性水平和抗性种群的乙酰乳酸合成酶(acetolactate synthase,ALS)靶标抗性机理,在温室内采用整株生物测定法测定21个猪殃殃种群对氯氟吡氧乙酸、苯磺隆和双氟磺草胺的抗性水平,同时根据猪殃殃ALS基因序列设计引物,提取猪殃殃高抗种群单株基因组DNA进行测序,并与拟南芥Arabidopsis thaliana敏感型ALS基因进行比对,查找突变位点分析其抗性机理。结果表明,21个猪殃殃种群对氯氟吡氧乙酸均敏感,尚未产生抗性;90.48%的猪殃殃种群已对苯磺隆产生了抗性,其中低抗、中抗和高抗种群分别占总种群数的23.81%、23.81%和42.86%,相对抗性指数最高为1 134.82;71.43%的猪殃殃种群已对双氟磺草胺产生了抗性,其中低抗、中抗和高抗种群分别占总种群数的19.05%、9.52%和38.10%,相对抗性指数最高为87.05。高抗苯磺隆种群XZ-1和LW均发生了ALS基因第197位氨基酸功能位点的突变,其中XZ-1种群发生了CCC(脯氨酸)到TCC(丝氨酸)...     

靶标基因突变导致入侵性杂草长芒苋对咪唑乙烟酸产生抗性

长芒苋Amaranthus palmeri生长迅速,适应性广,繁殖系数高,具有很强的竞争性,已在我国多地定植,对作物产量及生态环境构成潜在威胁.一旦其对除草剂产生抗性,将大大增加治理难度.本试验研究了采自不同地点的长芒苋种群对除草剂咪唑乙烟酸的抗性水平和抗性机理.整株生物测定得出,长芒苋疑似抗性种群和敏感种群对咪唑乙烟...     

Molecular basis of resistance to acetolactate synthase-inhibiting herbicides in Sisymbrium orientale and Brassica tournefortii

Three Australian Sisymbrium orientale and one Brassica tournefortii biotypes are resistant to acetolactate synthase (ALS)-inhibiting herbicides due to their possession of an ALS enzyme with decreased sensitivity to these herbicides. Enzyme kinetic studies revealed no interbiotypic differences within species in K_m (pyruvate) (the substrate concentration at which the reaction rate is half maximal) but a greater V_max (the rate when the enzyme is fully saturated with substrate) for two of the resistant S orientale biotypes over susceptible levels. F₁ hybrids from reciprocal crosses between resistant and susceptible biotypes of S orientale showed an intermediate response to chlorsulfuron compared to the parental plants. ALS herbicide resistance in S orientale segregated in a 3:1 (resistant:susceptible) ratio in F₂ plants with a single rate of chlorsulfuron, indicating that resistance is inherited as a single, incompletely dominant nuclear gene. Two regions of the ALS structural gene known to vary in ALS-resistant biotypes were amplified and sequenced. Resistant S orientale biotypes NS01 and SS03 contained a single nucleotide substitution in Domain B, predicting a Trp (in susceptible) to Leu (in resistant) amino acid change. Two adjacent nucleotide substitutions (CC T to AT T) predicting a Pro (in susceptible) to Ile (in resistant) change in the primary amino acid sequence were identified in Domain A of resistant S orientale biotype SS01. Likewise, a single nucleotide substitution at the same site in the resistant B tournefortii biotype predicts a Pro (in susceptible) to Ala (in resistant) substitution. No other interbiotypic nucleotide differences predicted amino acid changes in the sequenced regions, suggesting that the amino acid substitutions reported above are responsible for resistance to ALS-inhibiting herbicides in the respective biotypes. © 1999 Society of Chemical Industry     

Characterisation and molecular basis of ALS inhibitor resistance in the grass weed Alopecurus myosuroides

Several UK populations of the grass weed Alopecurus myosuroides were identified where high proportions of individuals showed resistance to the acetolactate synthase (ALS)‐inhibiting herbicides, mesosulfuron‐methyl + iodosulfuron‐methyl sodium mixture and sulfometuron‐methyl. Screening with sulfometuron, followed by DNA sequencing of the ALS gene from resistant and susceptible individuals, led to the identification of eight populations where a single point mutation segregated with resistance to sulfometuron. All highly resistant individuals from seven of eight populations showed a single‐nucleotide polymorphism (SNP) in the first position of the Pro197 codon of an A. myosuroides ALS gene, conferring a predicted proline to threonine target‐site change. One population showed resistant individuals with single‐nucleotide polymorphism in the second position of the Trp574 codon, conferring a predicted tryptophan to leucine substitution. No other mutations segregating with resistance were found. Enzyme assays confirmed that resistance was due to an altered form of ALS enzyme, which was less susceptible to inhibition by sulfonylureas, making this one of the first fully characterised cases of ALS target‐site resistance in a European grass weed. Increased information regarding the nature and distribution of ALS target‐site mutation may help support sustainable management strategies, allowing continued use of mesosulfuron + iodosulfuron against this weed in the UK.     

Herbicide resistance in Aster squamatus conferred by a less sensitive form of acetolactate synthase

A biotype of Aster squamatus (Sprengel) Hieronymus with suspected resistance to the ALS-inhibiting herbicide imazapyr was detected in a chicken farm in the province of Seville, Spain, which had been treated once a year with imazapyr for 10 years. Resistance to imazapyr in this biotype was studied using dose-response experiments, absorption and translocation assays, metabolism studies and ALS activity assays. The rate of imazapyr required to inhibit A squamatus growth by 50% (ED50) was 15 times higher for the R (resistant) than for the S (susceptible) biotype. Cross-resistance existed for the ALS-inhibitors imazamox, imazethapyr, amidosulfuron, nicosulfuron, rimsulfuron, triasulfuron and tribenuron, but not for bensulfuron. Control of A squamatus using alternative herbicides was poor with clopyralid, intermediate with quinclorac, amitrole and MCPA, and excellent with 2,4-D, glufosinate and glyphosate. Absorption of [14C]imazapyr increased over time for both the R and S biotypes, and translocation from the treated leaf to shoots and roots was similar in both biotypes, with most of the radioactivity remaining in the treated leaf. No metabolites of imazapyr were detected in either biotype. Sensitivity of the ALS enzyme (target site) to imazapyr was lower for the R biotype (I50(R) = 4.28 x I50(S)). The mechanism of imazapyr resistance in this R biotype appears to be an altered ALS conferring decreased sensitivity to imazapyr at the whole-plant level.     

抗苄嘧磺隆野慈姑乙酰乳酸合成酶的突变研究

近年来,野慈姑Sagittaria trifolia L.在中国东北稻区发生和危害日趋严重,部分稻区使用苄嘧磺隆已无法有效防除该杂草。为了明确野慈姑抗药性发生的根本原因,本试验从分子水平上对野慈姑抗苄嘧磺隆的机理进行了研究。通过对抗药性(H4)和敏感性(S)野慈姑种群靶标酶乙酰乳酸合成酶(ALS)基因片段进行扩增和克隆,比较其DNA序列的差异,确定导致抗药性产生的ALS氨基酸突变位点。结果表明,与敏感性野慈姑ALS基因相比,H4种群第197位脯氨酸(Pro)突变为苏氨酸(Thr),该位点的突变可能是H4野慈姑种群对苄嘧磺隆产生抗药性的主要原因。ALS第197位Pro突变为Thr致使对苄嘧磺隆产生抗药性是第一次在野慈姑种群中报道。     

Multiple resistance of Papaver rhoeas L. to 2,4‐D and acetolactate synthase inhibitors in four European countries

The issue of cross‐ or multiple resistance to acetolactate synthase (ALS) inhibitors and the auxinic herbicide 2,4‐D was investigated in Papaver rhoeas L., a common and troublesome weed in winter cereals, in a broad‐scale study across four European countries. A combination of herbicide sensitivity bioassays and molecular assays targeting mutations involved in resistance was conducted on 27 populations of P. rhoeas originating from Greece (9), Italy (5), France (10) and Spain (3). Plants resistant to the field rate of 2,4‐D were observed in 25 of the 27 populations assayed, in frequencies ranging from 5% to 85%. Plants resistant to ALS‐inhibiting herbicides (sulfonylureas) were present in 24 of the 27 populations, in frequencies ranging from 4% to 100%. Plants resistant to 2,4‐D co‐occurred with plants resistant to sulfonylureas in 23 populations. In four of these, the probability of presence of plants with cross‐ or multiple resistance to 2,4‐D and sulfonylureas was higher than 0.5. ALS genotyping of plants from the field populations or of their progenies, identified ALS alleles carrying a mutation at codon Pro197 or Trp574 in 2,4‐D‐sensitive and in 2,4‐D‐resistant plants. The latter case confirmed multiple resistance to 2,4‐D and ALS inhibitors at the level of individual plants in all four countries investigated. This study is the first to identify individual plants with multiple resistance in P. rhoeas, an attribute rarely assessed in other weed species, but one with significant implications in designing chemical control strategies.     

荠菜对乙酰乳酸合成酶抑制剂类除草剂的抗性水平及其分子机制

为明确荠菜种群对苯磺隆的抗性水平及其靶标抗性产生的分子机制,采用整株水平测定法测定了荠菜对苯磺隆及其他5种乙酰乳酸合成酶（ALS）抑制剂类除草剂的抗性水平,同时扩增和比对了荠菜抗性和敏感种群之间ALS基因的差异。结果显示:与敏感种群15-ZMD-1相比,抗性种群15-ZMD-5对苯磺隆产生了高水平抗性,抗性倍数为219.6;15-ZMD-5种群不同单株中共存在3种突变方式,分别为ALS基因197位点脯氨酸（CCT）突变为亮氨酸（CTT）、574位点色氨酸（TGG）突变为亮氨酸（TTG）以及单株同时发生上述197和574位点的氨基酸突变。15-ZMD-5抗苯磺隆种群对嘧草硫醚、啶磺草胺和氟唑磺隆均产生了高水平的交互抗性,抗性倍数分别为41.2、79.3和87.8;对双氟磺草胺和咪唑乙烟酸产生了低水平的交互抗性,抗性倍数分别为8.5和5.6。分析表明,荠菜抗性种群ALS基因发生的氨基酸突变可能是导致其对ALS抑制剂类除草剂产生抗性的重要原因之一。