Co-Authors:
Muschietti, J., Plant Gene Expression Center, U.S. Department of Agriculture, University of California at Berkeley, 800 Buchanan Street, Albany, CA 94710, United States, Inst. de Ing. Genet./Biol. Molecular, University of Buenos Aires, Vuelta de Obligado 2490, Buenos Aires (1428), Argentina
Eyal, Y., Plant Gene Expression Center, U.S. Department of Agriculture, University of California at Berkeley, 800 Buchanan Street, Albany, CA 94710, United States, Institute of Horticulture, Volcani Center, ARO, P.O. Box 6, Bet-Dagan 50250, Israel
McCormick, S., Plant Gene Expression Center, USDA-ARS, 800 Buchanan St., Albany, CA 94710, United States
Abstract:
We screened for pollen-specific kinase genes, which are potential signal transduction components of pollen-pistil interactions, and isolated two structurally related receptor-like kinases (RLKs) from tomato, LePRK1 and LePRK2. These kinases are similar to a pollen-expressed RLK from petunia, but they are expressed later during pollen development than is the petunia RLK. The abundance of LePRK2 increases when pollen germinates, but LePRK1 remains constant. Both LePRK1 and LePRK2 are localized to the plasma membrane/cell wall of growing pollen tubes. Both kinase domains have kinase activity when expressed in Escherichia coli. In phosphorylation assays with pollen membrane preparations, LePRK2, but not LePRK1, is phosphorylated, and the addition of tomato style, but not leaf, extracts to these membrane preparations results at least partially in specific dephosphorylation of LePRK2. Taken together, these results suggest that LePRK1 and LePRK2 play different roles in postpollination events and that at least LePRK2 may mediate some pistil response.