Increasing plant density increases Bt toxin concentration of boll wall in cotton by decreasing boll setting speed

• 作者: ZHOU Mingyuan CHEN Chen TAMBEL Leila I.M. CHEN Yuan ZHANG Xiang CHEN Dehua
• 来源期刊: 棉花研究（英文版）
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: RESEARCH
• 页码范围: 104-113
• 页数: 10页
• 语种: 英文

摘要

Background:In order to uncover the mechanism of significantly reduced insect resistance at the late developmental stage in cotton (Gossypium hirsutum L.),the relationship between boll setting rate under different planting densities and Bacillus thuringiensis (Bt) insecticidal concentrations in the boll wall were investigated in the present study.Two studies were arranged at Yangzhou,China during the 2017-2018 cotton growth seasons.Five planting densities(15000,25000,45000,60000 and 75000 plants per hectare) and the flower-removal treatment were imposed separately on Bt cotton cultivar Sikang3 to arrange different boll setting rates,and the boll setting rates and Bt toxin content were compared.Results:Higher boll setting rate together with lower Bt toxin contents in boll wall was observed under low planting density,whereas lower boll setting rate and higher Bt toxin contents were found under high planting density.Also,higher Bt protein concentration was associated with higher soluble protein content,glutamic-pyruvic transaminase(GPT),and glutamic oxaloacetate transaminase (GOT) activities,but lower amino acid content,and protease and peptidase activities.It was further confirmed that a higher boll setting rate with lower Bt protein content under flower-removal.Conclusions:This study demonstrated that the insecticidal efficacy of boll walls was significantly impacted by boll formation.Reduced protein synthesis and enhanced protein degradation were related to the reduced Bt toxin concentration.