NSF Award
2421658
Plant pollination leads to fruits and seeds, so is central to global ecology and the human food supply. Yet the details of how plants interact with pollinators to assure pollen is used efficiently to set the most seeds are still poorly understood. This project investigates key parts of plant reproductive signaling via a novel plant movement trait, rapid, touch-sensitive stigma closure (TSSC). The stigma is the first point of pollinator contact and controls which pollen grains may sprout and grow to fertilize seeds. Monkeyflowers (Mimulus) and related plant families have a bi-lobed stigma that snaps shut (like a tiny Venus flytrap) within a few seconds of touch and then re-opens only if it has not received enough pollen. Such fast closure likely ensures efficient pollination. But it also requires novel sensing and signaling systems similar to animal neural systems, as well as fine-scale control of water pressure in special hinge cells. This project builds on new genome resources and methods to investigate what genes were used to build this novel trait, how it works, and why it has been lost in some species. The research will generate basic knowledge important to everything from crop improvement to the design of soft robots, train diverse scientists in modern genomic and molecular methods, and create shared resources. Integrated outreach activities support hands-on learning about plants, pollinators, and genes for K-12 students.<br/><br/>A research team at the University of Montana builds on new chromosome scale-genome assemblies and molecular tools for Mimulus to investigate the origin, elaboration and loss of rapid TSSC. This trait occurs in at least 8 families across the core Lamiales but is missing from interdigitated families and is also repeatedly lost in highly self-fertilizing monkeyflowers. This provides a unique opportunity to address fundamental questions about the origins of complex, multi-trait evolutionary novelties and to determine the genetic and cellular mechanisms of plant touch- and pollen-sensing, signal transduction, fine-scale turgor regulation, and nastic movement. Project 1 uses comparative transcriptomics to trace the evolution of stigma gene networks across family-level TSSC transitions in Lamiales and in recent convergent losses in self-pollinating monkeyflowers. Project 2 dissects the genetic basis of TSSC variation in multiple Mimulus mapping populations to refine the genomic causes of repeated losses, identify key candidate genes, and isolate their functional effects. Project 3 uses genetic transformation and cellular genomic methods to explore and validate the candidate molecular, cellular, and signaling components of TSSC developed in the other two projects. Together, these projects advance basic understanding of plant reproductive sensing, signaling, morphology and movement, as well as the illuminate the evolutionary and genomic processes that generate complexity and novelty.<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.
