Effects of temperature, water content and pH on degradation of Cry1Ab protein released from Bt corn straw in soil

Effects of water management practices on residue decomposition and degradation of Cry1Ac protein from crop-wild Bt rice hybrids and parental lines during winter fallow season

“…A.1A) compared with the range of 0.5-11.4°C, 0.2-11.3°C and 7.7-15.4°C at the three sites in our previous study (Xiao et al, 2014), which may have led to the increased level of k c . These results confirm the effects of temperature and water content on the degradation of the Cry1Ab protein released from the Bt crop residue in field soil, similar to the laboratory results presented by Feng et al (2011) and Zhang et al (2015).We found that k c derived from both conditions was positively correlated with the initial concentration of the Cry1Ac protein in rice residues. This finding was supported by Wang et al (2007) who revealed that k c decreased as the concentration of purified Cry1Ab protein in aqueous solutions declined.…”

Fate of insecticidalBacillus thuringiensisCry protein in soil: differences between purified toxin and biopesticide formulation

“…Preliminary studies showed that there was no effect of moisture content on the dynamics of either biopesticide or purified Cry under laboratory conditions, suggesting that the difference was not due to the surface layer of the soil in the field being drier than for the laboratory study. Feng et al also report no effect of moisture content on the release of Cry1Ab from transgenic straw and its subsequent decline in soil.…”

“…We postulated that the fixation was dominated by hydrophobic interactions, as they are known to decrease with decreasing temperature. Feng et al reported an increase in the rate of decline in Cry1B in soil with increasing temperature, but it is impossible to distinguish between the temperature effect on release of protein from straw and its subsequent degradation or fixation on soil.…”

Bt rice cultivation does not cause soil biological degradation in terms of C, N, and P cycles

“…The root exudations occur during rice growth periods, and the inputs of detritus mainly occurs at harvest time, otherwise few Bt proteins entered soil. The Bt protein decomposed quickly in soil (Valldor, Miethling‐Graff, Martens, & Tebbe, ) with the half‐life ranging from 0.75 to 10.89 days (Feng et al, ), and no Bt protein was detected from soil at the beginning of next growth period (Gruber, Paul, Meyer, & Müller, ). Therefore, the short durations of Bt proteins in soil may be responsible for the high resilience of most soil properties (e.g., the activities of dehydrogenase and acid phosphatase and methane production) under the Bt rice cultivations (Table ).…”