Regeneration of Complex Patterns in Plants

The ability of some organisms to regenerate damaged body parts long after embryogenesis is a fascinating and critically important property. The remarkable capacity of plants to regenerate from almost any organ arises from their ability to recreate its organ-specific growth centers, known as meristems. Plant regeneration provides a unique model to learn how cells communicate during regeneration because plant cells are non-motile and must rely on cell-cell signaling to enable complex tissues to reform. In addition, plant regeneration has practical implications for human nutrition, as modern biotechnological techniques to improve crops rely on tissue regeneration. This MIRA renewal explores mechanisms that make up the plant’s self-organizing system that forms new organs during regeneration. Building on the prior work generated by the MIRA award (R35GM136362), the project uses techniques that uncover the wide repertoire of mobile transcription factors, microRNAs, and peptides that mediate pattern formation during regeneration. The technique uses inducible constructs that block communication from specific cells and then reads out the effect of the communication block in single-cell RNA-seq profiles, called Block-Seq. This renewal also embarks on the functional analysis of mobile signals, using highly parallel pooled CRISPR/single cell RNA-seq screens in whole plants to identify mutations with cell non-autonomous effects. In a second project related to signals in plant regeneration, this MIRA renewal examines how bursts of glutathione in the nucleus instigate rapid cell divisions that characterize the early steps of regeneration. The project investigates whether fast divisions, which prior results showed abbreviate the G1 phase of the cell cycle, are necessary to allow differentiated plant cells to reprogram after injury. In addition, the MIRA will open a third project to develop a model for regeneration that is a close relative of the most important crop plants, such as corn, rice, and wheat. Such a model will greatly aid in transferring regenerative properties to crop plants to speed the development of new crops that increase U.S. food security and improve the nutritional value of our diets. Overall, the project asks basic questions that will inform the wider field of regeneration and addresses a practical problem in plant biotechnology that directly impacts human health and nutrition.