Ph.D., Watson School of Biological Sciences at Cold Spring Harbor Laboratory, 2004
Plant developmental genetics; mechanisms of phase transitions for flowering time and inflorescence branching; heterosis
In plants, populations of pluripotent cells called shoot apical meristems (SAMs) give rise to all aboveground organs and guide overall morphology. The basic structure of a flowering plant can be reduced to two phases of meristem growth: the vegetative phase and the reproductive phase. Initial SAM growth produces a shoot with leaves and lateral (axillary) meristems, which form in the axils of leaves. The SAM then gradually enters the reproductive phase by transitioning to an inflorescence meristem (IM), which initiates flowers and axillary meristems that can either produce additional flower-producing axillary meristems or immediately become flowers. Although useful for understanding basic principles of meristem activity and potential, this simplified framework fails to explain the vast architectural diversity in the plant kingdom, especially the remarkable variation in the number and arrangement of branches. This is because when and where meristems form, whether they begin growing immediately or experience dormancy, how long they grow, how large they become, and the number of additional meristems they generate, all depend on plant-specific sensitivities to the environment and differential regulation of physiological and genetic programs. Our research aims to expose and understand the genetic and molecular mechanisms guiding branching, especially within inflorescences, which are responsible for plant reproductive success. We use tomato as a model system to address the hypothesis that the rate that meristems transition to a reproductive state (meristem maturation) along with meristem size are responsible for evolutionary differences in inflorescence architecture and flower production, and provide a foundation for improving crop yields.
The Tomato Genome Consortium. 2012. The tomato genome sequence provides insights into fleshy fruit evolution. Nature. 485: 635–641.
MacAlister, C. A., Park, S.J., Jiang, K., Marcel, F., Bendahmane, A., Izkovich, Y., Eshed Y., and Lippman, Z.B. 2012. Synchronization of the flowering transition by the tomato TERMINATING FLOWER gene. Nat. Genet. 44: 1393–1398.
Park, S.J., Jiang, K., Schatz, M.C., Lippman, Z.B. 2012. Rate of meristem maturation determines inflorescence architecture in tomato. Proc. Natl. Acad. Sci. 109: 639–644.
Krieger, U., Lippman, Z.B., and Zamir, D. 2010. The flowering gene SINGLE FLOWER TRUSS drives heterosis for yield in tomato. Nat. Genet. 42: 459–63.