Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, USA.
Institute of Plant Protection, Gansu Academy of Agricultural Sciences, Lanzhou, China.
Pest Manag Sci. 2019 Aug;75(8):2124-2132. doi: 10.1002/ps.5331. Epub 2019 Feb 25.
The fall armyworm, Spodoptera frugiperda (J.E. Smith), is the first target pest that has developed resistance to Bt crops across several countries. Leaf tissue and whole plant assays were employed to determine the survival, development, progeny production, and net reproductive rate of all nine possible genotypes of Cry1A.105/Cry2Ab2-dual gene resistant S. frugiperda on non-Bt and MON 89034 maize expressing the Cry1A.105/Cry2Ab2 proteins.
The homozygous resistant genotype was highly resistant to Bt plants. Genotypes possessing only Cry2Ab2 resistance alleles (RAs) or two Cry1A.105 RAs only were susceptible to MON 89034 with a functional dominance level (D ) of 0.0-0.07 on MON 89034 plants. In contrast, genotypes containing two Cry1A.105 plus one Cry2Ab2 RA performed well on Bt plants, with a D of 0.11-0.78. Significant numbers of survivors on Bt plants were also observed for genotypes containing a single Cry1A.105 RA, or a Cry1A.105 plus one or two Cry2Ab2 RAs, with a D of 0.0-0.47.
The fitness of individual resistant genes on pyramided Bt plants varied in the dual-gene resistance system. Genotypes containing more Cry1A.105 RAs performed better than those possessing more Cry2Ab2 RAs. The functional dominance level of an individual resistant gene in this system is related to the D level in its corresponding single-gene system. Data generated from this study should fill gaps in understanding dual-/multiple-gene Bt resistance, as well as providing useful information for refining resistance modeling, improving resistance risk assessment, and developing management strategies for the sustainable use of pyramided Bt maize technology. © 2019 Society of Chemical Industry.
秋黏虫（Spodoptera frugiperda）是第一个在多个国家对 Bt 作物产生抗性的靶标害虫。采用叶片组织和整株植物测定法，测定了 Cry1A.105/Cry2Ab2 双基因抗性 S. frugiperda 的所有 9 种可能基因型在非 Bt 和表达 Cry1A.105/Cry2Ab2 蛋白的 MON 89034 玉米上的生存、发育、后代生产和净生殖率。
纯合抗性基因型对 Bt 植株高度抗性。仅具有 Cry2Ab2 抗性等位基因（RA）或仅具有两个 Cry1A.105 RA 的基因型对 MON 89034 敏感，在 MON 89034 植株上的功能显性水平（D）为 0.0-0.07。相比之下，含有两个 Cry1A.105 加一个 Cry2Ab2 RA 的基因型在 Bt 植株上表现良好，D 值为 0.11-0.78。在 Bt 植株上也观察到含有单个 Cry1A.105 RA、或一个 Cry1A.105 加一个或两个 Cry2Ab2 RA 的基因型的大量存活个体，D 值为 0.0-0.47。
在双基因抗性系统中，单个抗性基因在组合 Bt 植株上的适应性不同。含有更多 Cry1A.105 RA 的基因型表现优于含有更多 Cry2Ab2 RA 的基因型。该系统中单个抗性基因的功能显性水平与相应的单基因系统中的 D 水平相关。本研究产生的数据应该有助于填补对双-/多基因 Bt 抗性的理解空白，为改进抗性建模、提高抗性风险评估以及开发可持续使用组合 Bt 玉米技术的管理策略提供有用信息。 © 2019 化学工业协会。
