| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 6389573 | Journal of Invertebrate Pathology | 2013 | 6 Pages |
Sugarcane borer, Diatraea saccharalis (F.), is a major target of Bt maize in South America and many areas of the US mid-south region. Six laboratory strains of D. saccharalis were established from six single-pair F2 families possessing major resistance alleles to Cry1Ab maize hybrids. Susceptibility of the six strains was evaluated on diet treated with each of four purified trypsin-activated Bt proteins, Cry1Ab, Cry1Aa, Cry1Ac and Cry1F. Bt susceptibility of the six strains was compared with that of known Cry1Ab-susceptible and -resistant strains of D. saccharalis. At least two of the six strains demonstrated a similar level (>526-fold) of resistance to Cry1Ab as shown in the known Cry1Ab-resistant strain, while resistance levels were relatively lower for other strains (116- to 129-fold). All the six strains were highly cross-resistant to Cry1Aa (71- to 292-fold) and Cry1Ac (30- to 248-fold), but only with a low level to Cry1F (<7-fold). Larval growth of all six strains was also inhibited on Bt-treated diet, but, except for Cry1F, the growth inhibition of the six strains was considerably less than that of the Cry1Ab-susceptible larvae. The results provide clear evidence that the observed resistance to Cry1Ab maize in the six strains is a result of resistance to the Cry1Ab protein in the plants. The low level of cross-resistance between Cry1A and Cry1F suggests that pyramiding these two types of Bt proteins into a plant could be a good strategy for managing D. saccharalis.
Graphical abstractDownload full-size imageHighlights⺠Six Diatraea saccharalis strains were established from survivors on Bt maize. ⺠All six strains were highly resistant to Cry1Ab, Cry1Aa, and Cry1Ac proteins. ⺠The six strains exhibited only a low level of cross-resistance to Cry1F protein. ⺠The survival on Bt maize is a result of resistance to Cry1Ab in the plants. ⺠Pyramiding Cry1A and Cry1F into a plant could be a good strategy.
