Plants have developed sophisticated mechanisms for recognizing and responding to their environment and for integrating environmental cues to coordinate growth, development, and stress/defense responses. Plant hormones play a central role in mediating these processes with the hormone salicylic acid (SA) as a major regulator of plant defense. SA synthesis is induced in response to pathogens and turns on a broad spectrum of defense responses that limit the extent of infection. When SA synthesis is limited, plants are more susceptible to a broad range of pathogens. However, if SA is made prematurely or is always being synthesized at elevated levels, there is a negative impact on growth. Therefore understanding how SA is made and modified to control its activity is essential to understanding plant defense and its associated impact on growth. This knowledge can then be exploited to enhance agricultural productivity.
Despite the importance of SA in plant defense, its biosynthetic pathway has not been fully defined. Furthermore, the role of the SA-amino acid conjugate SA-Asp, detected in diverse plants, has not been established. Funding has been limited by controversy in the field, with proof of proposed pathways and modifications being required by some reviewers as a prerequisite to funding. Therefore, this project is considered high risk - high reward. Using the model genetic/genomic plant Arabidopsis thaliana, the investigators will use molecular genetic, biochemical, and analytical approaches to obtain convincing preliminary data defining (1) the full pathogen-induced SA biosynthetic route via isochorismate and (2) the importance of SA-Asp in plant defense. Basic research in Arabidopsis on induced SA metabolism and defense has translated to commercially important species, allowing for enhanced productivity. In addition, this project will train two graduate students and two undergraduates, including a first generation college-educated student. Finally, the investigator is committed to fostering the next generation of scientists through programs at local Berkeley public schools in which >45% of students are from under-represented groups and >40% qualify for free lunch. In particular, the investigator initiated and developed a new STEM outreach program for 7th graders entitled "Be A Scientist" in which each student develops and explores their own scientific question over the course of a semester in concert with UC Berkeley scientist volunteers and staff of Community Resources for Science, a local non-profit providing practical support for great science teaching.
