{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T14:05:15Z","timestamp":1789740315702,"version":"4.0.1"},"reference-count":53,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T00:00:00Z","timestamp":1789603200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100012659","name":"Foundation for Innovative Research Groups of the National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["31972281"],"award-info":[{"award-number":["31972281"]}],"id":[{"id":"10.13039\/501100012659","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Plant Sci."],"abstract":"<jats:p>\n                    As a malignant weed in paddy systems,\n                    <jats:italic>Cyperus difformis<\/jats:italic>\n                    L. (\n                    <jats:italic>C. difformis<\/jats:italic>\n                    ) has evolved resistance to acetohydroxyacid synthase (AHAS, EC 2.2.1.6), also known as acetolactate synthase (ALS), inhibiting herbicides such as pyrazosulfuron-ethyl and bensulfuron-methyl due to prolonged selection pressure. This study systematically investigated the interaction mechanisms between mutated AHAS and these herbicides through biochemical and structural approaches. In this study, purified AHAS proteins of five mutated types and the wild type were obtained via prokaryotic expression, and their sensitivity and affinity for pyrazosulfuron-ethyl and bensulfuron-methyl were determined. The structural differences in different binding of AHAS binding to the two herbicides were identified via homology modeling and molecular docking. The sensitivity determination of purified AHAS indicated that AHAS with site 197 mutations had higher GR\n                    <jats:sub>50<\/jats:sub>\n                    and I\n                    <jats:sub>50<\/jats:sub>\n                    values for pyrazosulfuron-ethyl (25.60\u201374.78 \u03bcM) than for bensulfuron-methyl (6.62\u201338.32 \u03bcM). The AHAS with a site 376 mutation had higher GR\n                    <jats:sub>50<\/jats:sub>\n                    and I\n                    <jats:sub>50<\/jats:sub>\n                    values for bensulfuron-methyl than for pyrazosulfuron-ethyl, while the GR\n                    <jats:sub>50<\/jats:sub>\n                    and I\n                    <jats:sub>50<\/jats:sub>\n                    values of the AHAS with a site 574 mutation were the highest. The affinity of purified AHAS for the substrate revealed that all the mutations increased the affinity except for the Pro-197-Arg mutation. In addition, all the AHAS mutants had greater affinity for bensulfuron-methyl than for pyrazosulfuron-ethyl. Molecular docking results revealed that AHAS formed hydrogen bonds, \u03c0\u2013\u03c0 bonds, and hydrophobic interactions with pyrazosulfuron-ethyl and bensulfuron-methyl. The total number and types of interactions with pyrazosulfuron-ethyl and benzosulfuron-methyl were obviously different between the mutant AHAS and wild-type AHAS. Therefore, in this study, different mutations in AHAS induced distinct structural alterations, which reduced the affinity of the enzyme for herbicides, consequently leading to the development of weed resistance. The difference in affinity between the same mutant and the two herbicides led to a difference in resistance to the two herbicides. The results of this study are helpful for understanding the causes of weed resistance to herbicides at the structural level.\n                  <\/jats:p>","DOI":"10.3389\/fpls.2026.1932845","type":"journal-article","created":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T13:27:11Z","timestamp":1789738031000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["AHAS structural changes caused by mutations result in differences in binding affinity and resistance to two herbicides in Cyperus difformis L."],"prefix":"10.3389","volume":"17","author":[{"given":"Xiaotong","family":"Guo","sequence":"first","affiliation":[{"name":"State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences","place":["Beijing, China"]},{"name":"Institute of Plant Protection, Heilongjiang Academy of Agricultural Sciences, Heilongjiang","place":["Harbin, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiangju","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingchao","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linzhi","family":"Bai","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Haiyan","family":"Yu","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hailan","family":"Cui","sequence":"additional","affiliation":[{"name":"State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences","place":["Beijing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,17]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"209","DOI":"10.1016\/j.ab.2008.03.035","article-title":"Determining kinetics and affinities of protein interactions using a parallel real-time label-free biosensor, the Octet","volume":"377","author":"Abdiche","year":"2008","journal-title":"Anal. 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