Hector E. Flores - US grants

This symposium provides an up-to-date assessment of our knowledge of the biosynthesis, metabolism and molecular biology of polyamines and ethylene. Presentations by outstanding researchers in the field will provide a critical analysis of the involvement of polyamines and ethylene in plant growth, development, and responses to stress. The antagonistic roles of these molecules in senescence, plant stress and development will be examined, as well as the possible regulatory mechanisms for the ethylene and polyamine pathways. Polyamines and ethylene are the two important topics that will be discussed during the 5th Annual Penn State Symposium in Plant Physiology. Polyamines are compounds that have been implicated as markers for male fertility and in flower development. Evidence also suggests that polyamines may retard senescence. Ethylene has been shown to play an important regulatory role in many physiological processes including sex expression, flower initiation and the promotion of senescence. The purpose of this symposium is to address a variety of topics on polyamine and researchers working on these two distinct yet overlapping subjects and provide a catalyst for innovative approaches in the future. The symposium will provide students and post doctoral fellows an unusual opportunity to meet and interact in a small group setting with the leaders in this research area. The published proceedings will provide an up-to-date review of research in these rapidly advancing fields which will be of general value to students and scientists in colleges and universities, government, and industry.

The proposed project is to study the functional aspects of pistil S-proteins and regulation of S-gene expression in gametophytic self-incompatibility. Using Nicotiana alata and Petunia inflata, Dr. Kao will 1) establish direct evidence that S-proteins are responsible for the self-incompatibility reaction by testing the effect on self-incompatibility behavior of introducing either a new S-gene into plants homozygous for a different S-allele, or an antisense S-gene into plants homozygous for the same S-allele; 2) identify the s-allele specificity domain of the S-protein by using chimeric S-proteins expressed in transgenic plants; 3) test the effect of mutating the conserved cysteine residues of S- proteins on their function; 4) determine the sequences controlling tissue specific and developmentally regulated expression of S-genes by fusing their 5' upstream sequences to a reporter gene, GUS, and then using sequential deletion to test the effect on expression of GUS in transgenic plants; 5) identify a protein associated with the style activity part of the S-locus using a unique self-compatible style-part mutant of N. alata. The result of these experiment will yield important information on the molecular basis of self-incompatibility. %%% Many higher plants have a mechanism, termed self-incompatibility, with prevents the pollen from a given plant from self fertilizing the female tissue (pistil) of the same plant. Genes controlling this self- incompatibility have been identified but the mechanism whereby the incompatibility occurs is unknown. In addition to its inherent interest to plant biologists, there are clear applications to agriculture to an understanding of this process.

This is a unit of DOE/NSF/USDA Collaborative Research in Plant Biology Program. The theme of the interdisciplinary research training group is root biology, and is designed to nurture a group of innovative and creative scientists capable of developing and utilizing an interdisciplinary team approach to plant biology. The three major focus areas include root ecology, root biochemistry and root/organism interactions. The group involves 13 faculty members all interested in various aspects of root biology from root growth, plant nutrition and nitrogen fixation to soil chemistry/physics. Research training involves training of graduate students, postdocs, a seminar series, retreats, an international symposium, and internships in private and government facilities. Outreach activities include mentoring gifted high school students and professional improvement of high school teachers. The investigators hope to develop this group into a inter-departmental center for root biology at Penn State University.

The studies proposed here focus on the physiology and biochemistry of the polyacetylenes, fatty acid derivatives which are present mainly in the roots of Asteraceae. Polyacetylenes show a wide range of biological activities (nematicidal, fungicidal and antiviral), and may play an important role in protecting plant roots against challenge from soil pathogens. By transformation with Agrobacterium rhizogenes, we have obtained "hairy roots" cultures of five genera in the Asteraceae. These fast growing roots have shown stable, long-term production of root polyacetylenes and are therefore an ideal experimental system. Using precursor label incorporation, HPLC and GC-MS analysis, and cell-free assays, we propose to establish the pathway for polyacetylene biosynthesis in root cultures. Fungal and nematodal bioassays have been developed, and will be used to monitor the biological activity of the polyacetylenes produced in rootcultures. The de novo formation of polyacetylenes in root cultures can be induced by treatment with fungal elicitors. This approach will be used to identiy the rate-limiting enzymatic steps in polyacetylene biosynthesis, and test the proposed involvement of lipoxygenase. Although roots normally grow heterotrophically both in isolated culture and "in planta", we have found that they can also be grown photosynthetically and photoautotrophically. We will also study the quantitative and qualitative effects of photosynthesis and photoautotrophy on root polyacetylene patterns. ***//

Signal transduction is emerging as an important principle underlying much of plant development and adaptation to the environment. Signaling often involves multiple levels of response, from organ, tissue and cell interactions to events at the level of membranes, cytoplasm and gene expression. In our view, the most informative analyses of signal transduction involve multidisciplinary approaches where the signal is characterized through its multiple levels and forms of expression (genetic, biochemical, physical, physiological, etc.) We propose to establish a graduate training program with innovations in our instructional approach and research guidance with faculty from six (6) departments to pursue collaborative research across multiple levels of signal transduction. Toward this goal, we will develop a problem-based learning course to explore multiple facets of plant signal transduction. Graduate students will engage in multidisciplinary research by attacking research problems at the interface of two (or more) research efforts. An annual Distinguished Investigator seminar/workshop series and concluding international symposium will provide additional opportunity for student development. Our program will enrich the background and "tool-kit" available to the next generation, as well as the current generation, of researchers to investigate the mechanisms by which plants develop and react to their environment.

The 2002 annual meeting of the Phytochemical Society of North America will bring together (for the first time) chemical ecologists, biochemists, natural products chemists, molecular biologists, biomedical researchers and ethnobotanists/pharmacologists with the goal of developing an integrative synthesis of these traditional and modern approaches. Symposia will address ways in which these subdisciplines can inform each other about the evolution, function, and potential applications of plant products. Submitted presentations also will address the meeting theme, "Integrative Phytochemistry: From Ethnobotany to Molecular Ecology". This meeting will provide an unprecedented intersection of biology, chemistry, sociology and medecine and should produce truly novel, international and cross-cultural collaborative opportunities.
The meeting will be held in Merida, Mexico; attendees will come from all over North America and Europe (at least), and strong representation by Mexican and other Latin American scientists and students is expected. Meeting organizers highlight participation by students and younger scientists by organizing a 'young researcher' symposium and seeking support for travel by students, postdocs, and junior researchers. Proceedings will be published as a volume in the widely-read "Recent Advances in Phytochemistry" series.