Division of Plant Biotechnology, Indian Institute of Pulses Research, Kalyanpur, Kanpur, India.
Division of Basic Sciences, Indian Institute of Pulses Research, Kalyanpur, Kanpur, India.
Sci Rep. 2020 Mar 25;10(1):5453. doi: 10.1038/s41598-020-62199-1.
Symbiotic nitrogen fixation (SNF) of transgenic grain legumes might be influenced either by the site of transgene integration into the host genome or due to constitutive expression of transgenes and antibiotic-resistant marker genes. The present investigation confirmed proper nodulation of five tested Bt-chickpea events (IPCa2, IPCa4, IPCT3, IPCT10, and IPCT13) by native Mesorhizobium under field environment. Quantitative variations for nodulation traits among Bt-chickpea were determined and IPCT3 was found superior for nodule number and nodule biomass. Diversity, as well as richness indices, confirmed the changes in bacterial community structure of root and root-nodules from Bt-chickpea events IPCa2 and IPCT10. Especially, Gram-positive bacteria belonging to Firmicutes and Actinobacteria were selectively eliminated from root colonization of IPCa2. Richness indices (CHAO1 and ACE) of the root-associated bacterial community of IPCa2 was 13-14 times lesser than that of parent cv DCP92-3. Root nodule associated bacterial community of IPCT10 was unique with high diversity and richness, similar to the roots of non-Bt and Bt-chickpea. It indicated that the root nodules of IPCT10 might have lost their peculiar characteristics and recorded poor colonization of Mesorhizobium with a low relative abundance of 0.27. The impact of Bt-transgene on bacterial community structure and nodulation traits should be analyzed across the years and locations to understand and stabilize symbiotic efficiency for ecosystem sustainability.
转基因豆科作物的共生固氮（SNF）可能受到转基因整合到宿主基因组的位置或转基因和抗生素抗性标记基因的组成型表达的影响。本研究通过田间环境下的本地中慢生根瘤菌证实了五个测试的 Bt 鹰嘴豆事件（IPCa2、IPCa4、IPCT3、IPCT10 和 IPCT13）的适当结瘤。Bt 鹰嘴豆之间的结瘤特性存在定量变化，IPCT3 在根瘤数量和根瘤生物量方面表现出色。多样性和丰富度指数证实了根和根瘤中 Bt 鹰嘴豆事件 IPCa2 和 IPCT10 的细菌群落结构发生了变化。特别是，属于厚壁菌门和放线菌门的革兰氏阳性菌从 IPCa2 的根定植中被选择性消除。与根相关的细菌群落的丰富度指数（CHAO1 和 ACE）IPCa2 比亲本 cv DCP92-3 少 13-14 倍。IPCT10 的根瘤相关细菌群落具有独特的高多样性和丰富度，类似于非 Bt 和 Bt 鹰嘴豆的根。这表明 IPCT10 的根瘤可能已经失去了其特有特征，并且中慢生根瘤菌的定植较差，相对丰度为 0.27。Bt 转基因对细菌群落结构和结瘤特性的影响应在多年和多个地点进行分析，以了解和稳定共生效率，实现生态系统可持续性。
