Zachary Lippman
Assistant Professor
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
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My laboratory explores molecular mechanisms regulating the time and place where plants make their flowers, using tomato as a model system. The transition to flowering and the generation of the branches the bear flowers, called inflorescences, depend on highly integrated developmental ‘phase transitions’ that occur within groups of pluripotent stem cells, called meristems.
We study mutations that affect inflorescence architecture to expose mechanisms of inflorescence meristem patterning. We isolated two genes, ANANTHA (AN – a protein whose primary function is to target other proteins for degradation) and COMPOUND INFLORESCENCE (S – a transcription factor), which transform the few-flowered tomato ‘vine’ into a highly branched structure. These genes have little effect on branching in meristems that grow endlessly (monopodial/indeterminate), like Arabidopsis. However, S and AN function sequentially to promote branch termination in species where meristem growth ceases with flower production (sympodial/determinate). These genes reveal a new phase transition whereby inflorescence elaboration in sympodial plants, like trees, is controlled through floral fate. We are now using a suite of molecular/genomic tools to identify the molecular networks that control how and when sympodial shoot meristems undergo phase transitions from leaf production to flower production.
A second focus, in the laboratory, is exploring why some hybrids are more fertile than their parents (heterosis). We use phenotypic variation from wild tomato species to study heterosis quantitative trait loci (QTL), which regulate the rate of inflorescence production. We also discovered that mutations in flowering genes can cause heterosis, and we are exploring the role of pleiotropic dosage effects of these genes on plant development as a potential mechanism.
Please visit Zach's Lab home page.
Selected Publications
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.
Lippman, Z.B., Zamir, D. 2007 Heterosis: Revisiting the magic. Trends in Genetics. 23: 60-66
Lippman, Z.B., Semel, Y., Zamir, D. 2007 An integrated view of quantitative trait variation using tomato interspecific introgression lines. Current Opinion in Genetics and Development. 6:545-552.
