Cyanobacterial inoculation in elevated CO2 environment stimulates soil C enrichment and plant growth of tomato

The present study investigated the influence of cyanobacterial inoculants viz., Anabaena laxa (A.laxa) ), Calothrix elenkinii (C. elenkinii) and Anabaena torulosa- Trichoderma viride (An-Tr) under ambient (aCO(2)) and elevated (eCO(2)) conditions, on soil and plant parameters, when grown with/without tomato crop. Significant enhancement in soil chlorophyll, proteins, polysaccharide content, total leaf pigments and C-N assimilating enzyme activities was recorded under elevated CO2 conditions with cyanobacterial inoculation, when grown with/without tomato crop. Supplementation with A. laxa led to more than a fold-enhancement in polysaccharides and 40%-45% increment in available nitrogen, while An-Tr recorded 60%-70% increase in soil microbial biomass carbon under elevated CO2 condition. A. laxa treatment also recorded highest plant pigments, glutamine synthetase and carbonic anhydrase activity under elevated CO2 condition. Distinct influence of elevated CO2 condition, cyanobacterial inoculation and plant and their interactions were recorded. Interestingly, plants grown under elevated CO2 showed early flowering, by eight days, compared to ambient conditions. Phospholipid fatty acid profiles of soil samples illustrated significant changes in the total biomass and distribution of notional microbial groups due to inoculation and the presence of plant. Multivariate analyses illustrated the significant interactions among the soil and microbiological attributes, highlighting that cyanobacterial inoculation can be a promising intervention to utilize beneficially the elevated CO2 for enhancing soil nutrients, crop growth and productivity in tomato. (C) 2022 The Authors. Published by Elsevier B.V.