Data from: Spatial soil heterogeneity has a greater effect on symbiotic arbuscular mycorrhizal fungal communities and plant growth than genetic modification with Bacillus thuringiensis toxin genes

Maize, genetically modified with the insect toxin genes of Bacillus thuringiensis is widely cultivated, yet its impacts on soil organisms are poorly understood. Arbuscular mycorrhizal fungi (AMF) form symbiotic associations with plant roots and may be uniquely sensitive to genetic changes within a plant host. In this field study, the effects of nine different lines of Bt maize and their corresponding non-Bt parental isolines were evaluated on AMF colonization and community diversity in plant roots. Plants were harvested 60 days after sowing and data were collected on plant growth and percent AMF colonization of roots. AMF community composition in roots was assessed using 454 pyrosequencing of the 28S rRNA genes and spatial variation in mycorrhizal communities within replicated experimental field plots was examined. Growth responses, percent AMF colonization of roots, and AMF community diversity in roots did not differ between Bt and non-Bt maize, but root and shoot biomass and percent colonization by arbuscules varied by maize cultivar. Plot identity had the most significant effect on plant growth, AMF colonization, and AMF community composition in roots, indicating spatial heterogeneity in the field. Mycorrhizal fungal communities in maize roots were autocorrelated within approximately 1 m, but at greater distances, AMF community composition of roots differed between plants. Our findings indicate that spatial variation and heterogeneity in the field has a greater effect on the structure of AMF communities than host plant cultivar or modification by Bt toxin genes.表达苏云金芽孢杆菌（Bacillus thuringiensis）杀虫毒素基因的转基因玉米（Bt玉米）已被广泛推广种植，但其对土壤生物的潜在影响尚未得到充分阐释。丛枝菌根真菌（Arbuscular mycorrhizal fungi, AMF）可与植物根系形成互惠共生关系，且可能对宿主植物的遗传变化具有独特的敏感性。本田间试验评估了9个不同品系的Bt玉米及其对应的非Bt亲本近等基因系对植物根系AMF定殖率与群落多样性的影响。研究于播种后60天收获植株，收集植株生长性状及根系AMF定殖百分比相关数据；采用28S rRNA基因的454焦磷酸测序技术对根系AMF群落组成进行分析，并检测重复田间试验样地内菌根群落的空间变异特征。结果显示，Bt玉米与非Bt玉米的生长响应、根系AMF定殖率及根系AMF群落多样性均无显著差异，但玉米的根系与地上部生物量以及丛枝定殖百分比则因品种不同而存在差异。样地差异对植株生长、AMF定殖及根系AMF群落组成具有最显著的影响，表明田间生境存在显著的空间异质性。玉米根系内的菌根真菌群落在约1米范围内呈现空间自相关特征，但当距离超过该阈值时，不同植株的根系AMF群落组成会出现显著分化。本研究结果表明，相较于宿主植物品种或Bt毒素基因改造，田间的空间变异与异质性对AMF群落结构的调控作用更为显著。