Probing active microbes involved in Bt-containing rice straw decomposition

Area of Science:

• Agricultural Science
• Environmental Microbiology
• Molecular Biology

Background:

• Transgenic Bacillus thuringiensis (Bt) rice offers insect resistance, crucial for food and energy security.
• While Bt rice's ecosystem impact is studied, its influence on active soil microbial communities remains less understood.
• Understanding microbial responses to Bt rice is vital for assessing its environmental sustainability.

Purpose of the Study:

• To investigate the impact of Bt rice presence on active microbial communities during straw decomposition.
• To identify specific microbial taxa and functional traits affected by Bt straw decomposition.
• To determine the duration and significance of these microbial changes.

Main Methods:

• Stable isotope probing (SIP) combined with high-throughput sequencing to identify active microbes.
• Analysis of chemical composition of Bt and non-Bt rice straw.
• Similarity index calculation and functional prediction for microbial communities.

Main Results:

• Bt straw exhibited higher N, P, K, lignin, cellulose, and Cry1Ab toxin content compared to non-Bt straw.
• Bt straw decomposition significantly altered active microbial decomposer communities, with fungi being more affected than bacteria.
• Unique bacterial genera (Agromyces, Terrabacter, Microbacterium, Glycomyces, Kribbella) and fungal genus (Trichoderma) were identified in Bt straw decomposition.
• Differences in microbial taxa and functional traits between Bt and non-Bt straw treatments were transient.

Conclusions:

• Bt rice significantly influences active soil microbial communities involved in straw decomposition.
• The identified unique microbial genera suggest specific roles in Bt straw degradation.
• Despite significant initial changes, the impact of Bt rice on soil microbial communities and functions is temporary.