October 1992 1'173 zy MEETING REPORT en process, particularly those whose absence is lethal or whose function is par- tially redundant with that of some other gene product. It is also essential, there- fore, to analyze genes whose sequences resemblethose of proteins of known func- tion. Together, these approaches will have much to divulge about the mechanisms plant cells use to perceive signals as diverse as phytohormones, pathogen eli- citors, and pollen. Rebecca Chasan REFERENCES Dzelzkalns, V.A., Nasrallah, J.B., and Nasrallah, M.E. (1992). Cell-cell communi- cation in plants: Self-incompatibility in flower development. Development 153, 70-82. Finkelstein, R.R., and Somerville, C.R. (1990). Three classes of abscisic acid (ABA)-insen- sitive mutations of Arabidopsis define genes that control overlapping subsets of ABA re- sponses. Plant Physiol. 94, 1172-1179. Hashimoto, C., Hudson, K.L., and Anderson, K.V. (1988). The zyxwvuts To// gene of Drosophila, re- quired for dorsal-ventral embryonic polarity, appears toencode atransmembrane protein. Cell 52, 269-279. Hattori, T., Vasil, V., Rosenkrans, L., Han- nah, L.C., McCarty, DA., and Vasil, I.K. (1992). The Viviparous-7 gene and abscisic acid activate the C7 regulatory gene for anthocyanin biosynthesis during seed matu- ration in maize. Genes Dev. 6, 609-618. Koornneef, M., Reuling, G., and Kansen, C.M. (1984). The isolationand characteriza- tion of abscisic acid-insensitive mutants of Arabidopsis thaliana. Physiol. Plant. 61, 377-383. Koornneef, zyxwvutsrq M., Hanhart, C.J., Hilhorst, H.W.M., and Karssen, C.M. (1989). In vivo inhibition of seed development and reserve protein accumulationin recombinants of ab- scisic acid biosynthesis and responsiveness mutants inArabidopsis thaliana. Plant Phys- iol. 90, 463-469. McCarty, D.R., Hattori, T., Canon, C.B., Vasil, V., Lazar, M., and Vasil, I.K. (1991). The Friends and Foes: New lnsights into Plant-Microbe lnteractions FromJuly 11 to 16,1992, severa1hundred scientists from around the world met in Seattle, Washington, to attend the Sixth lnternational Symposium on Molecular Plant-Microbe Interactions,which was or- ganized by Eugene Nester. This series of meetings, which was begun 10years ago, has already spawned a new society, the lnternational Society of Molecular Plant- Microbe Interactions,and hasfostered the explosive development of molecular stud- ies on plant-microbe interactions. The following discussion touches on a few of the highlights among the many oral and poster presentations. Agrobacterium-Plant lnteractions Research on the interaction of zyxwv Agrobac- terium tumefaciens with its plant host gave rise to the modern technology of plant transformation and the birth of the plant biotechnology industry. Research on this interesting plant pathogen continues to have broad ramifications. Agrobacterium colonizes plant wounds and genetically colonizes the plant by incorporation of T-DNA into the plant genome. One of the earliest steps in this interaction is the at- tachment of Agrobacterium to the wound site. A number of mutants have been iso- Viviparous-7 developmental gene of maize encodes a nove1transcriptional activator. Cell Nambara, E., Naito, S., and McCourt, P. (1992). A mutant of Arabidopsis which is defective in seed development and storage protein ac- cumulation is a new abi3 allele. Plant J. 2, Stein, J.C., Howlett, B., Boyes, D.C., Nasrallah, M.E., and Nasrallah, J.B. (1991). Molecular cloning of a putative receptor protein kinase gene encoded at the self-incompatibility lo- cus of Brassica oleracea. Proc. Natl. Acad. Sci. USA 88, 8816-8820. Tobias, C.M., Howlett, B., and Nasrallah,J.B. (1992). An Arabidopsis thaliana gene with se- quence similarity to the S-locus receptor kinase of Brassica oleracea. Plant Physiol. Ullrich, A., and Schlessinger, J. (1990). Sig- na1 transduction by receptors with tyrosine kinase activity. Cell 61, 203-212. 66, 895-905. 435-441. 99, 284-290. Walker, J.C., and Zhang, R. (1990). Relation- shipof a putative receptorprotein kinasefrom maize to the S-locus glycoproteins of Bras- sica. Nature 345, 743-746. lated that appear to be defective in attachment, but analysis of these mutants has thus far failed to reveal the molecular mechanismof attachment.Therefore, the poster presented by Anne Mathysse and Vincent Wagner (Universityof North Caro- lina) was of particular interest. These authors presented evidence that a plant vitronectin-likeprotein may be the surface receptor for Agrobacterium binding to carrot cells. Vitronectin, an adhesive gly- coprotein found in the extracellular matrix, is involved in mammaliancell attachment. The poster by Saskia Swart (Leiden University)offered a candidate for the bac-