Research Summary:

In response to pathogens and herbivores, plants employ up-regulation and down-regulation of diverse genes to achieve resistance. Research in my lab centers on two areas: 1) molecular mechanisms of down-regulation of gene expression during the plant defense response and its biological significance; 2) understanding the functions of specific defense-down-regulated genes during normal growth and development. We are especially focused on analyzing signaling pathways linking pathogen recognition and mRNA degradation. The mRNA for a bean cell wall protein, PvPRP1, is rapidly degraded during the defense response. The PvPRP1 protein fails to undergo a cross-linking reaction characteristic of disease resistance, hence providing a biological rationale for its down-regulation. The upstream signaling pathway and the physiological advantage accrued by mRNA down-regulation are being investigated in transgenic Arabidopsis. In contrast, a related Arabidopsis cell wall protein gene, AGP31,exhibits transcriptional down-regulation to a defense signaling molecule, jasmonic acid. AGP31 mutant plants exhibit an unusual developmental change and we are interested to understand this linkage. A third research area involves the use of algae for biofuels. Our lab is examining the effects of biotic and abiotic stresses on a model algal species, the diatom Phaseodactylum tricornatum, at the molecular level.