Acta Entomologica Sinica (2005) 48, 208-213

Mao Chen, Gong-Yin Ye, Xin-Min Lu, Cui Hu, Yu-Fa Peng, Qing-Yao Shu and Altosaar Illimar (2005)
[Biotransfer and bioaccumulation of Cry1Ab insecticidal protein in rice plant-brown planthopper-wolf spider food chain]
Acta Entomologica Sinica 48 (2), 208-213
Abstract: The concentration of Cry1Ab insecticidal protein expressed in two homozygous transgenic Bacillus thuringiensis (Bt) rice lines, KMD1 and KMD2, were determined by enzyme immunosorbent assay (ELISA) with the PathoScreen kit for Bt cry1Ab/Ac protein (Agdia, USA). The results showed that the concentration of Cry1Ab expressed both in KMD1 and KMD2 at the heading and maturing stage were significantly lower than that at the seedling, tillering and booting stage. CrylAb protein could be transferred from transgenic rice plants to its nontarget pest brown planthopper (BPH), Nilaparvata lugens (Stal), and from N. lugens to its natural enemy wolf spider (WS), Pirata subpiraticus (Boesenberg et Strand) in the food chain by preying. The quantitative cycle of Cry1Ab insecticidal protein in the food chain was analyzed using the kit. After being fed on KMD1 or KMD2 rice plants for 2 days, Cry1Ab protein could be detected in the N. lugens body. However, after continuous feeding on Bt rice plants for 2, 4, 6, 8 and 10 days, the content of Cry1Ab remaining in the N. lugens body did not show the expected tendency of increase. Also, Cry1Ab protein could be detected in the P. subpiraticus body by preying on the N. lugens reared on KMD1 or KMD2 rice plants for 2, 4, 6, 8 or 10 days, while their contents were significantly higher than those of N. lugens fed on KMD1 or KMD2 for the same time. Although the inoculation time was increased from 2 to 4, 6, 8 and 10 days, the level of Cry1Ab detected in P. subpiraticus did not show any increase. Additionally, there were no significant differences among the predatory consumptions of P. subpiraticus preying on N. lugens reared on KMD1, KMD2 or on the non-transgenic parental rice line Xiushui11. No clear bioaccumulation pattern of Cry1Ab protein was observed in N. lugens and P. subpiraticus. More than 50 percent of Cry1Ab was degraded by the crude protease extract from the midgut of P. subpiraticus at 37°C without light for 2 hours. However, as the exposure time increased from 2 to 4, 8, 12 and 24 hours, the detoxification function of the crude protease extract did not show a tendency to increase.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Chinese)
Database assignments for author(s): Cui Hu, Mao Chen

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Nilaparvata lugens	Rice (Oryza)
Pirata subpiraticus (predator)	Nilaparvata lugens	Rice (Oryza)
Bacillus thuringiensis genes in crops (entomopathogen)
Bacillus thuringiensis Cry1A-toxin (entomopathogen)