Grant: Discovery Grants Program - Individual

Agricultureis a key sector of the Canadian economy.Increased productivity isamajor goal of breeding programs.Plant architectureis a major determinant of crop yield. The long-term objective of my research program is to understand how genes control plant shape and form . This information is valuable in genomics-assisted breeding which seeks to use knowledge of genes and genomes to customize agronomic traits in crop plants. Plant shape and form relies on the activity of self-perpetuating groups of stem cells called meristems. Meristems provide a continuous supply of daughter cells for incorporation into new leaves, flowers, and shoots throughout the life cycle. Our work focuses on the role of organ boundaries located at the meristem periphery. Boundaries are narrow domains of restricted growth that separate the meristem from new organs as they form. These domains areessential for meristem maintenance and organ outgrowth. These domainsare also the source of axillary meristems that give rise to branches and flowers on the inflorescence and the site of abscission zones that control the detachment of fruits, leaves, and flowers. Despite the agronomicimportance of boundaries to plant architecture, little is known about the genetic networks that control their function. Our work has identified BLADE-ON-PETIOLE (BOP) transcription factors and their downstream targets as major determinants of plant architecture functioningat organ boundaries. This module regulates reproductive meristem development, inflorescence branching, andspecification ofabscission zones. A much broader role for this module in fruit development, organ detachment, and plant defense is suggested by expression patterns andtranscriptome analysis of downstream target genes. Over the next five years, we will investigate these links in the model plant species, Arabidopsis thaliana (Arabidopsis). Our proposed researchfocuses onfour areas: (1) Role of the BOP module in fruit development, (2) Module function in abscission, (3) TGA transcription factors acting as BOP co-factors at boundaries, and (4) Role of BOPs in plant defense. This work providesimportant training opportunities for3 Ph.D. students,3 M.Sc. students, and 3-4 undergraduateHQPper year who will take an active role in knowledge discovery. Significance: BOPshave been identified as regulating a variety of important agronomic traits linked to crop yield including tillering in barley, leaf complexity and inflorescence architecture in tomato, and abscission in legumes. An understanding of how these genes control development at boundaries brings us one step closer tocustomization of plants for agriculture.