Linking Genotype Specific Interkingdom Communication with Shifts in Environmental P Pools Reveals New Insights into Plant-Microbe-Environment Resource Utilization

Increasing demand on global agriculture and growing pressures from climate change urge more sustainable crop phosphorus utilization efficiency (PUE). Functional organisms in the rhizosphere are important in nutrient cycling and availability, with selection for these organisms recently revealed to be regulated by plant genotype. Polyphosphate accumulating organisms (PAOs) are a poorly understood rhizomicrobiome community characterized by accumulation of P as inorganic polyphosphate (polyP) to serve as a biologic P pool for energy production and nutrient storage. Our previous efforts revealed PAO community structure is regulated by key maize N genotypes. Essential to utilizing PAOs for enhancing PUE, spatiotemporal variations in biologically active P pools in the rhizosphere remain unknown, key N relevant genotype specific variations in P pool utilization have yet to be explored, and the interaction of PAOs with key biologically relevant P pools are unelucidated stemming from lack of phylogenetic knowledge and detailed spatiotemporal P species profiling. In parallel with fluorescence activated cell sorting-16S, biologically relevant P pools were quantified using DeLuca’s Biologically Based P (BBP) Sequential Extraction in the rhizosphere of NRT1 and wildtype (wt) lines over growth. Non-metric Multi-Dimensional Scaling (NMDS) reveals distinct variations (stress<0.2) in P pool utilization between NRT1 and wt during development with NRT1 P pools clustering more closely, revealing potentially tighter regulation of P pool utilization via the knockdown of the NRT1 gene relative to its wildtype. Key correlative variations in P pool utilizations were observed with wt exhibiting positive correlation with readily labile P while NRT1 exhibited a unique correlation with metal bound P not observed in the wt. Interestingly, a unique sinusoidal correlative behavior was observed conserved between NRT1 and wt lines suggesting concentration specific behavior of the PAO community relative to P pool utilization. Of these key relationships, we observed a highly conserved Pseudomonas ASV2 significantly (p<0.01) correlating with phosphatase-P and metal bound P. Other significant relationships observed include Methylobacterium-Methylorubrum, a C cycle mediating methylotroph, correlating with weakly labile organic and phosphatase P (p<0.05) as well as metal complexed P (p<0.01) and N cycle mediating Nitrospira similarly correlating with phosphatase-P (p<0.01), suggesting co-C, N, and P regulation by maize genotype specific PAO communities is impacted by P pool specific interactions.

My summer internship was full of making fun memories and learning about plant science. I was given a good understanding of what graduate school is like from getting to work on my own research project and being involved in lab meetings. Through working with my mentor, I gained lab and research skills and confidence that will help me in future endeavors. I appreciated the opportunity to learn about science communication and do a science outreach event because it was a fun and unique experience. Most of all, I enjoyed getting to talk to so many plant scientists because learning about their work and passions inspire me in my future plans. I am so grateful to everyone who helped me and for being given this opportunity!