Reis Alexandre C, Steinhaus Eduardo A, Godoy Daniela N, Warpechowski Luiz F, Diniz Luis H M, Dallanora Arthur, Horikoshi Renato J, Ovejero Ramiro F L, Martinelli Samuel, Berger Geraldo U, Head Graham P, Dourado Patrick M, Bernardi Oderlei
Department of Plant Protection, Federal University of Santa Maria, Santa Maria, Brazil.
Regulatory Science, Bayer Crop Science, São Paulo, Brazil.
Pest Manag Sci. 2025 Feb;81(2):727-735. doi: 10.1002/ps.8475. Epub 2024 Oct 15.
Rachiplusia nu (Guenée) was historically a secondary soybean pest in Brazil, but a key soybean pest in Argentina. From 2021 onwards, injury caused by R. nu has been reported in soybean that expresses the Cry1Ac toxin from Bacillus thuringiensis (Berliner) in both countries. In this study, we selected resistant and susceptible strains of R. nu to Cry1Ac using Cry1Ac-containing leaf tissue and characterized the inheritance of resistance, cross-resistance patterns and fitness cost.
Neonates of the Cry1Ac-resistant strain of R. nu were able to develop on Cry1Ac soybean leaves and emerge as fertile adults, while neonates from the susceptible and heterozygous strains did not survive beyond 10 days. The resistance ratio to Cry1Ac estimated in diet-overlay bioassays in the resistant strain was > 736.92-fold. The inheritance pattern of Cry1Ac resistance in R. nu was characterized as autosomal recessive and monogenic. The Cry1Ac-resistant strain of R. nu also exhibited high resistance to Cry1A.105 (resistance ratio > 159.87-fold), but negligible resistance to Cry2Ab2 (resistance ratio = 1.25-fold). Life history data showed that the resistance to Cry1Ac in R. nu is not associated with a substantial fitness cost.
The inheritance pattern of Cry1Ac resistance in R. nu is autosomal recessive, monogenic and not associated with obvious fitness costs. Cross-resistance occurred between Cry1Ac and Cry1A.105 in R. nu but not between Cry1Ac and Cry2Ab2, indicating that Cry1A.105/Cry2Ab2/Cry1Ac soybean is a valuable tool to manage Cry1Ac resistance in R. nu. This is the first study reporting the genetic basis of Cry1Ac resistance in R. nu. © 2024 Society of Chemical Industry.
棉夜蛾（Rachiplusia nu）（古内）在历史上是巴西大豆的次要害虫，但却是阿根廷大豆的主要害虫。从2021年起，在这两个国家中，表达来自苏云金芽孢杆菌（Berliner）Cry1Ac毒素的大豆中均已报道了棉夜蛾造成的危害。在本研究中，我们使用含Cry1Ac的叶片组织筛选了对Cry1Ac具有抗性和敏感性的棉夜蛾品系，并对抗性的遗传、交互抗性模式和适合度代价进行了表征。
棉夜蛾Cry1Ac抗性品系的幼虫能够在含Cry1Ac的大豆叶片上发育并羽化为可育成虫，而敏感品系和杂合品系的幼虫在10天内无法存活。在抗性品系的饲料覆盖生物测定中，对Cry1Ac的抗性倍数估计>736.92倍。棉夜蛾对Cry1Ac抗性的遗传模式被表征为常染色体隐性单基因遗传。棉夜蛾Cry1Ac抗性品系对Cry1A.105也表现出高抗性（抗性倍数>159.87倍），但对Cry2Ab2的抗性可忽略不计（抗性倍数=1.25倍）。生活史数据表明，棉夜蛾对Cry1Ac的抗性与显著的适合度代价无关。
棉夜蛾对Cry1Ac抗性的遗传模式为常染色体隐性、单基因遗传且与明显的适合度代价无关。棉夜蛾中Cry1Ac与Cry1A.105之间存在交互抗性，但Cry1Ac与Cry2Ab2之间不存在交互抗性，这表明Cry1A.105/Cry2Ab2/Cry1Ac大豆是管理棉夜蛾对Cry1Ac抗性的有价值工具。这是首次报道棉夜蛾对Cry1Ac抗性遗传基础的研究。©2024化学工业协会。
