{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T05:18:11Z","timestamp":1787807891615,"version":"build-2784847793"},"reference-count":49,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T00:00:00Z","timestamp":1787788800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012166","name":"National Key Research and Development Program of China","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100012166","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Plant Sci."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>\n                      High-temperature stress significantly impacts Cry1Ac endotoxin efficacy in\n                      <jats:italic>Bacillus thuringiensis<\/jats:italic>\n                      (Bt) cotton, yet the effects of realistic day\/night temperature fluctuation remain unclear.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>Hence, a 2-year (2021-2022) plot experiment was carried out to investigate the response of square Cry1Ac endotoxin concentration to fluctuating high temperature (HDT\/NNT, 38\/27\u00a0\u00b0C) compared with a control treatment (CK, 32\/25\u00a0\u00b0C) in cultivars \u2018Sikang 1\u2019 and \u2018Sikang 3\u2019.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>The results indicated that the Cry1Ac endotoxin concentration remained stable under CK but decreased significantly under HDT\/NNT only after 7 days of stress, with the decline intensifying over time. In 2021, the reduction was 14.18% and 30.88% on the 7th day and 10th day for S1, respectively, and 11.32% and 25.21% for S3. Physiologically, this reduction coincided with decreased soluble protein content and glutamate-oxaloacetate transaminase and glutamic-pyruvic transaminase activities, alongside increased free amino acid content and protease and peptidase activities.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>We hypothesize that normal night temperatures provide temporary physiological compensation against daytime high-temperature stress damage, maintaining a dynamic balance between Cry1Ac synthesis and degradation. However, as high-temperature stress persists between 4 and 7 days, the cumulative damage exceeds the nighttime compensatory capacity limit, which quantitatively and qualitatively disrupts this metabolic equilibrium by day 7, accelerating endotoxin loss. In summary, prolonged high-temperature stress (approximately 1 week) at the peak square stage in the field environments requires close monitoring and timely agricultural interventions.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fpls.2026.1913082","type":"journal-article","created":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T04:27:46Z","timestamp":1787804866000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Day\/night temperature fluctuations delay the high-temperature-induced decline in Cry1Ac endotoxin concentration in cotton squares"],"prefix":"10.3389","volume":"17","author":[{"given":"Yuting","family":"Liu","sequence":"first","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Run","family":"Ou","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ziyi","family":"Gu","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wenkai","family":"Gao","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuan","family":"Chen","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiang","family":"Zhang","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dehua","family":"Chen","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory of Crop Genetics and Physiology\/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University","place":["Yangzhou, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,27]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"433","DOI":"10.56454\/UQHD2285","article-title":"Genetic basis for variability of Cry1Ac expression among commercial transgenic Bacillus thuringiensis (Bt) cotton cultivars in the United States","volume":"8","author":"Adamczyk","year":"2004","journal-title":"J. Cotton Sci."},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.30848\/PJB2021-1(38)","article-title":"Effect of natural high temperature and flooding conditions on cry1ac gene expression in different transgenic Bt cotton (Gossypium hirsutum L.) cultivars","volume":"53","author":"Ahmad","year":"2021","journal-title":"Pak. J. Bot."},{"key":"B3","doi-asserted-by":"publisher","first-page":"18","DOI":"10.20088\/j.cnki.jxau.2000.01.004","article-title":"Study on the damage and loss of the second generation cotton bollworm and control thresholds in the northern cotton-growing areas of Xinjiang","author":"Baishan","year":"2000","journal-title":"J. Xinjiang Agric. Univ."},{"key":"B4","doi-asserted-by":"publisher","first-page":"248","DOI":"10.1016\/0003-2697(76)90527-3","article-title":"A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding","volume":"72","author":"Bradford","year":"1976","journal-title":"Anal. Biochem."},{"key":"B5","article-title":"Climate change 2023: synthesis report. First","volume-title":"Intergovernmental Panel on Climate Change (IPCC)","author":"Calvin","year":"2023"},{"key":"B6","doi-asserted-by":"publisher","first-page":"333","DOI":"10.1016\/j.envexpbot.2004.04.004","article-title":"The effect of high temperature on the insecticidal properties of Bt Cotton","volume":"53","author":"Chen","year":"2005","journal-title":"Environ. Exp. Bot."},{"key":"B7","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1046\/j.1365-2761.2002.00360.x","article-title":"Quantification using ELISA of Bacillus thuringiensis insecticidal protein expressed in the tissue of transgenic insect-resistant cotton","volume":"13","author":"Chen","year":"1997","journal-title":"Jiangsu J. Agric."},{"key":"B8","doi-asserted-by":"publisher","first-page":"141","DOI":"10.1016\/j.fcr.2012.08.015","article-title":"The effects of the relative humidity on the insecticidal expression level of Bt cotton during bolling period under high temperature","volume":"137","author":"Chen","year":"2012","journal-title":"Field Crops Res."},{"key":"B9","doi-asserted-by":"publisher","first-page":"2623","DOI":"10.13287\/j.1001-9332.20140618.002","article-title":"Effects of high temperature on Bt proteins expression and nitrogen metabolic physiology in square of Bt cotton at the peak squaring stage","volume":"25","author":"Chen","year":"2014","journal-title":"Chin. J. Appl. Ecol."},{"key":"B10","doi-asserted-by":"publisher","first-page":"114","DOI":"10.1016\/j.plaphy.2019.05.017","article-title":"Nitrogen deficit decreases seed Cry1Ac endotoxin expression in Bt transgenic cotton","volume":"141","author":"Chen","year":"2019","journal-title":"Plant Physiol. Biochem."},{"key":"B11","doi-asserted-by":"publisher","DOI":"10.3389\/fpls.2018.00051","article-title":"Nitrogen (N) application gradually enhances boll development and decreases boll shell insecticidal protein content in N-deficient cotton","volume":"9","author":"Chen","year":"2018","journal-title":"Front. Plant Sci."},{"key":"B12","doi-asserted-by":"publisher","DOI":"10.3389\/fpls.2022.1082926","article-title":"Low temperature decreased insecticidal protein contents of cotton and its physiological mechanism","volume":"13","author":"Chen","year":"2023","journal-title":"Front. Plant Sci."},{"key":"B13","doi-asserted-by":"publisher","first-page":"1836","DOI":"10.1016\/s2095-3119(12)60188-9","article-title":"Effects of extreme air temperature and humidity on the insecticidal expression level of bt cotton","volume":"11","author":"Chen","year":"2012","journal-title":"J. Integr. Agric."},{"key":"B14","doi-asserted-by":"publisher","first-page":"438","DOI":"10.5424\/sjar\/2013112-2854","article-title":"The recovery of Bt toxin content after temperature stress termination in transgenic cotton","volume":"11","author":"Chen","year":"2013","journal-title":"Span. J. Agric. Res."},{"key":"B15","doi-asserted-by":"publisher","first-page":"21","DOI":"10.1111\/j.1439-037X.2006.00240.x","article-title":"Variability of endotoxin expression in bt transgenic cotton","volume":"193","author":"Dong","year":"2007","journal-title":"J. Agron. Crop Sci."},{"key":"B16","doi-asserted-by":"publisher","first-page":"422","DOI":"10.1111\/jac.12462","article-title":"Quantifying individual and interactive effects of elevated temperature and drought stress on cotton yield and fibre quality","volume":"207","author":"Gao","year":"2021","journal-title":"J. Agron. Crop Sci."},{"key":"B17","doi-asserted-by":"publisher","first-page":"1293","DOI":"10.1126\/science.244.4910.1293","article-title":"Genetically engineering plants for crop improvement","volume":"244","author":"Gasser","year":"1989","journal-title":"Science"},{"key":"B18","doi-asserted-by":"publisher","first-page":"26","DOI":"10.2307\/1310643","article-title":"Evolutionary Biology and Genetically Engineered Crops: Consideration of evolutionary theory can aid in crop design","volume":"38","author":"Gould","year":"1988","journal-title":"BioScience"},{"key":"B19","doi-asserted-by":"publisher","first-page":"205","DOI":"10.1016\/j.cropro.2008.09.014","article-title":"Efficacy of transgenic cotton plant containing the Cry1Ac and Cry2Ab genes of Bacillus thuringiensis against Helicoverpa armigera and Syllepte derogata in cotton cultivation in Burkina Faso","volume":"28","author":"H\u00e9ma","year":"2009","journal-title":"Crop Prot."},{"key":"B20","doi-asserted-by":"publisher","first-page":"27","DOI":"10.3724\/SP.J.1006.2016.01374","article-title":"The effect of high-temperature stress on Bt protein content and nitrogen metabolism in the boll shell of Bt cotton","volume":"28","author":"Heng","year":"2016","journal-title":"J. Cotton. Sci."},{"key":"B21","doi-asserted-by":"publisher","first-page":"1702","DOI":"10.1093\/jee\/toaf089","article-title":"Lethal and sublethal effects of cotton expressing single and pyramided proteins of Bacillus thuringiensis (Bt) on Helicoverpa armigera (Lepidoptera: Noctuidae), Spodoptera litura (Lepidoptera: Noctuidae), and Spodoptera frugiperda (Lepidoptera: Noctuidae)","volume":"118","author":"Holman","year":"2025","journal-title":"J. Econ. Entomol."},{"key":"B22","doi-asserted-by":"publisher","DOI":"10.1016\/j.stress.2023.100151","article-title":"The insecticidal efficacy and performance of Bt Cotton under variable abiotic stresses \u2013 A review on recent findings","volume":"8","author":"Jehangir","year":"2023","journal-title":"Plant Stress"},{"key":"B23","doi-asserted-by":"publisher","first-page":"4032","DOI":"10.1016\/j.jia.2023.11.013","article-title":"Mepiquat chloride increases the Cry1Ac protein content of Bt cotton under high temperature and drought stress by regulating carbon and amino acid metabolism","volume":"23","author":"Jin","year":"2024","journal-title":"J. Integr. Agric."},{"key":"B24","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2416091121","article-title":"Mismatch between lab-generated and field-evolved resistance to transgenic Bt crops in Helicoverpa zea","volume":"121","author":"Legan","year":"2024","journal-title":"Proc. Natl. Acad. Sci. U.S.A."},{"key":"B25","doi-asserted-by":"publisher","first-page":"3419","DOI":"10.1016\/j.jia.2024.03.029","article-title":"Optimizing the Bacillus thuringiensis (Bt) protein concentration in cotton: Coordinated application of exogenous amino acids and EDTA to reduce spatiotemporal variability in boll and leaf toxins","volume":"23","author":"Liu","year":"2024","journal-title":"J. Integr. Agric."},{"key":"B26","doi-asserted-by":"publisher","DOI":"10.1186\/s42397-019-0042-1","article-title":"Bt insecticidal efficacy variation and agronomic regulation in Bt cotton","volume":"2","author":"Liu","year":"2019","journal-title":"J. Cotton Res."},{"key":"B27","doi-asserted-by":"publisher","first-page":"1237","DOI":"10.1603\/0022-0493-94.5.1237","article-title":"Effects of Bt cotton and Cry1Ac toxin on survival and development of pink bollworm (Lepidoptera: Gelechiidae)","volume":"94","author":"Liu","year":"2001","journal-title":"J. Econ. Entomol."},{"key":"B28","doi-asserted-by":"publisher","DOI":"10.3390\/agronomy12030668","article-title":"Recovery characteristics of cry1Ac endotoxin expression and related physiological mechanisms in bt transgenic cotton squares after high-temperature stress termination","volume":"12","author":"Liu","year":"2022","journal-title":"Agronomy."},{"key":"B29","doi-asserted-by":"publisher","first-page":"1485","DOI":"10.1016\/j.cropro.2008.06.006","article-title":"Individual and combined effects of salinity and waterlogging on Cry1Ac expression and insecticidal efficacy of Bt cotton","volume":"27","author":"Luo","year":"2008","journal-title":"Crop Prot."},{"key":"B30","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0170379","article-title":"Effects of soil salinity on the expression of bt toxin (Cry1Ac) and the control efficiency of helicoverpa armigera in field-grown transgenic bt cotton","volume":"12","author":"Luo","year":"2017","journal-title":"PloS One"},{"key":"B31","doi-asserted-by":"publisher","first-page":"1007","DOI":"10.1603\/0022-0493-98.3.1007","article-title":"Season-long variation in expression of Cry1Ac gene and efficacy of Bacillus thuringiensis toxin in transgenic cotton against Helicoverpa armigera (Lepidoptera: Noctuidae)","volume":"98","author":"Olsen","year":"2005","journal-title":"J. Econ. Entomol."},{"key":"B32","doi-asserted-by":"publisher","first-page":"103","DOI":"10.30574\/msarr.2023.7.1.0030","article-title":"Journey of genetically modified crops: Status and prospects","volume":"7","author":"Rout","year":"2023","journal-title":"Magna Sci. Adv. Res. Rev"},{"key":"B33","doi-asserted-by":"publisher","first-page":"311","DOI":"10.13140\/RG.2.2.20720.30723","article-title":"Effect of nitrogen fertigation and sowing time on the expression of Cry2Ab and on mortality of Spodoptera litura in Bollgard II cotton","volume":"35","author":"Saini","year":"2014","journal-title":"J. Environ. Biol."},{"key":"B34","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1104\/pp.64.1.1","article-title":"Nitrogen Fixation, Nodule Development, and Vegetative Regrowth of Alfalfa (Medicago sativa L.) following Harvest","volume":"64","author":"Vance","year":"1979","journal-title":"Plant Physiol."},{"key":"B35","doi-asserted-by":"publisher","first-page":"339","DOI":"10.1111\/ppl.12592","article-title":"Carbohydrate metabolism in the subtending leaf cross-acclimates to waterlogging and elevated temperature stress and influences boll biomass in cotton (Gossypium hirsutum)","volume":"161","author":"Wang","year":"2017","journal-title":"Physiol. Plant"},{"key":"B36","doi-asserted-by":"publisher","first-page":"2583","DOI":"10.13287\/j.1001-9332.201808.030","article-title":"Effects of high temperature on Bt proteins expression and nitrogen metabolic physiology in square of Bt cotton at the peak squaring stage","volume":"29","author":"Wang","year":"2018","journal-title":"Chin. J. Appl. Ecol."},{"key":"B37","doi-asserted-by":"publisher","first-page":"106","DOI":"10.1016\/j.fcr.2008.07.008","article-title":"Boll size affects the insecticidal protein content in Bacillus thuringiensis (Bt) cotton","volume":"110","author":"Wang","year":"2009","journal-title":"Field Crops Res."},{"key":"B38","doi-asserted-by":"publisher","first-page":"561","DOI":"10.1007\/BF00385542","article-title":"Levels of indole-3-acetic acid in intact and decapitated coleoptiles as determined by a specific and highly sensitive solid-phase enzyme immunoassay","volume":"153","author":"Weiler","year":"1981","journal-title":"Planta."},{"key":"B39","doi-asserted-by":"publisher","first-page":"884","DOI":"10.1104\/pp.64.5.884","article-title":"Ribulose bisphosphate carboxylase and proteolytic activity in wheat leaves from anthesis through senescence","volume":"64","author":"Wittenbach","year":"1979","journal-title":"Plant Physiol."},{"key":"B40","doi-asserted-by":"publisher","first-page":"220","DOI":"10.1016\/j.jip.2007.03.012","article-title":"Monitoring and management strategy for Helicoverpa armigera resistance to Bt cotton in China","volume":"95","author":"Wu","year":"2007","journal-title":"J. Invertebr. Pathol."},{"key":"B41","doi-asserted-by":"publisher","first-page":"41","DOI":"10.19336\/j.cnki.trtb.1998.03.015","article-title":"Colorimetric determination method of plant transaminase (GOT and GPT) activity and its application","volume":"29","author":"Wu","year":"1998","journal-title":"Chin. J. Soil Sci."},{"key":"B42","doi-asserted-by":"publisher","first-page":"1733","DOI":"10.3864\/j.issn.0578-1752.041127","article-title":"The expression of Bt toxin gene under different thermal treatments","volume":"37","author":"Xia","year":"2004","journal-title":"Scientia Agric. Sin."},{"key":"B43","doi-asserted-by":"publisher","DOI":"10.1039\/an9558000209","article-title":"The determination of amino-acids with ninhydrin","volume":"80","author":"Yemm","year":"1955","journal-title":"Analyst"},{"key":"B44","doi-asserted-by":"publisher","DOI":"10.3390\/insects16020115","article-title":"The effects of different cotton varieties on the growth and feeding preferences of helicoverpa armigera","volume":"16","author":"Yue","year":"2025","journal-title":"Insects"},{"key":"B45","doi-asserted-by":"publisher","first-page":"1991","DOI":"10.1016\/S2095-3119(17)61878-1","article-title":"Dynamics of Bt cotton Cry1Ac protein content under an alternating high temperature regime and effects on nitrogen metabolism","volume":"17","author":"Zhang","year":"2018","journal-title":"J. Integr. Agric."},{"key":"B46","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1111\/jac.12438","article-title":"Analysis of differentially expressed proteins affecting insecticidal protein content in Bt cotton under high-temperature and water deficit stress using label-free quantitation","volume":"207","author":"Zhang","year":"2021","journal-title":"J. Agron. Crop Sci."},{"key":"B47","doi-asserted-by":"publisher","first-page":"28","DOI":"10.1016\/j.jip.2007.03.012","article-title":"Monitoring and management of Helicoverpa armigera resistance to transgenic Bt cotton in Northern China","volume":"11","author":"Zhao","year":"2000","journal-title":"Resist. Pest Manage."},{"key":"B48","doi-asserted-by":"publisher","first-page":"235","DOI":"10.11963\/cs20240048","article-title":"Effects of exogenous growth regulators on Bt protein content and nitrogen metabolism in cotton boll shell under high temperature and drought stress","volume":"37","author":"Zhao","year":"2025","journal-title":"J. Cotton Sci."},{"key":"B49","doi-asserted-by":"publisher","first-page":"467","DOI":"10.2134\/agronj2018.08.0520","article-title":"Square insecticidal protein concentration relate to its biomass in bt cotton","volume":"111","author":"Zhou","year":"2019","journal-title":"Agron. J."}],"container-title":["Frontiers in Plant Science"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpls.2026.1913082\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T04:27:55Z","timestamp":1787804875000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fpls.2026.1913082\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,27]]},"references-count":49,"alternative-id":["10.3389\/fpls.2026.1913082"],"URL":"https:\/\/doi.org\/10.3389\/fpls.2026.1913082","relation":{},"ISSN":["1664-462X"],"issn-type":[{"value":"1664-462X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,27]]},"article-number":"1913082"}}