Symbiotic nitrogen fixation and endophytic bacterial community structure in Bt-transgenic chickpea (Cicer arietinum L)

Abstract

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.

Metagenomic analysis of microbial consortia native to the Amazon, Highlands, and Galapagos regions of Ecuador with potential for wastewater remediation

“…Although the other identified taxonomic groups have not been reported as part of the core microbial groups commonly found in wastewater communities, different studies have shown that these organisms have versatile metabolisms that can contribute to wastewater remediation. For instance, Sphingomonas and Shinella have been reported as genera involved in nitrogen fixation (Alok et al, 2020 ; Bizjak et al, 2023 ), phosphate fixation (Asaf et al, 2020 ; Jin et al, 2020 ; Liu et al, 2019 ), carbohydrate metabolism (Anderson & Wood, 1969 ), and photosynthesis (Kopejtka et al, 2021 ; Lu et al, 2022 ). Furthermore, while Pedobacter is a less studied genus, it has been associated with nitrogen fixation and phosphate fixation (Liang et al, 2022 ; Vannier et al, 2023 ); and Parachlorella and the bacterial genus Sphingopyxis are recognized for their ability to participate in photosynthesis (Kopejtka et al, 2021 ; Sharma et al, 2021 ; Vello et al, 2018 ).…”

Effects of Dual Inoculation with Irradiated or Non-Irradiated Streptomyces alfalfae Strain XY25 and Mesorhizobium ciceri on Yield and Plant Performance of Chickpea

“…It is consistent with those obtained by Dahalet al, (2017) who said that the abilities of some genera belonging to four phyla such as Actinomycetes, Bacteroidetes, Proteobacteria and Firmicutes can increase the activity of atmospheric nitrogen-fixing bacteria. Additionally, Alok et al (2020), found that the investigation of Bt-chickpea root and nodule endophytic bacterial community structure showed that in the four phyla detected, Actinobacteria accounted for 0.17% of the phyla Proteobacteria, Cyanobacteria, Firmicutes, and Actinobacteria. According to Abadi et al (2020) who found that the attendance rate of these four phyla is affected by the host plant.…”

Engineering Host Microbiome for Crop Improvement and Sustainable Agriculture

“…The frequent application of microbial communities as bioinoculants for increased nutrient mobilization, stress resilience, and plant growth-promoting traits has been well documented (ALKahtani et al, 2020;Alok et al, 2020). Magallon-Servin et al ( 2020) designed a consortia of phosphate rock-solubilizing bacteria for testing their capacity in phosphate solubilization, biofilm formation, and root colonization.…”