This project will develop advanced microscopy techniques for visualizing many different molecules at the same time within plant cells, thus contributing to understanding of how plants grow, reproduce and interact with disease causing microbes. This investment in developing multiplex microscopy will provide novel plant focused and other non-biomedical applications for the greater scientific community. This project will be leveraged for training scientists at all ranks up to principal investigators. Tomorrow’s scientists will be trained through active participation in the Donald Danforth Plant Science Center (DDPSC) NSF-Research Experiences for Undergraduates (REU) Program, teaching an advanced imaging short course, recruitment of high school students for imaging projects and participation in a regional internship program for high school students called Students and Teachers As Research Scientists (STARS). Additionally, the highly successful DDPSC Education and Outreach program will host workshops for teachers and provide interactive mentoring that connects our scientists with nearby schools including Harris Stowe University, a Historically Black College and University. In collaboration with The Bio-Analytic Resource for Plant Biology, this effort will share plant data online, and actively communicate and disseminate newly developed multiplex techniques through the NSF funded Plant Cell Atlas initiative, a community resource with the goal to build an integrated high-resolution molecular map of plant cells. The results from this effort will be disseminated in peer-reviewed publications, at scientific meetings, in hands-on/online workshops, training videos and a searchable online database.<br/><br/>One contemporary challenge in biology is to understand how large numbers of diverse molecules are distributed within cells and tissues. To address this, spatial-omics techniques are transforming the way we understand complex organisms. One form, “multiplex” microscopy, has been applied largely for biomedical applications to understand human disease, but is virtually unused in plants. This project will develop a transformative and versatile pipeline for multiscale plant tissue arrays using multiplex microscopy, probing nucleic acids, proteins and polysaccharides for correlated light, super-resolution and electron microscopy on the same sample, while preserving cell ultrastructure. The multiplex technique will be validated on select plant systems to create high-dimensional multiplex datasets of 1) cellular/cell wall modifications during abscission, 2) protein, mRNA and sRNA localization in anthers during small RNA biogenesis, and 3) host-pathogen interactions at infection sites.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.