Effect of Water Deficit on fungal community

We explored the impact of water deficit (WD) on the diversity, community composition, and associations between multi-kingdom rhizosphere microbial groups (bacteria, fungi, and protists) of corn and sugar beet. We tested the following hypotheses. First, we hypothesized that WD will have variable influence on the rhizosphere microbial community composition of different microbial groups (bacteria, fungi, and protists). Second, we hypothesized that WD will decrease the stability of microbial co-existence networks by influencing inter-kingdom interactions. To test our hypothesis, we collected rhizosphere soil samples from 8 sites across four mid-western states in the US. We specifically selected for sites where corn and sugar beet were growing in adjacent fields, and the irrigation was maintained through center-pivot (also known as waterwheel and circle irrigation). Under these conditions a natural moisture gradient can be observed between the inner (>20 rows) and the outer (<15 rows) of planted crops. Thus, here, water stress is represented by a prolonged reduction in water availability compared with fully irrigated (IR) plants closer to the water source. We aimed to explore the taxonomic differences between the microbiomes of WD and IR plants using amplicon (for bacteria, fungi, and protists) sequencing. We also compared the inter-kingdom microbial networks of WD and irrigated plant microbiomes to offer insights into the connectedness and proportion of positive/negative interactions, which serves as a measure of network stability; the hubs within the network, which indicates prominent microbial groups; as well as highly correlated taxonomic groups, indicating microbes that tend to co-exist with one another. We provide novel evidence that WD significantly affects microbial community taxonomic composition and co-occurance network structures in the rhizosphere, which have implications for the potential changes in their ecological functions under climate change.