Poster: Plant Systems Biology

Abs # P48005: Role of tobacco salicylic acid methyl transferase in disease resistance signaling

Presenter:	Hotz, Tazley A       Contact Presenter
Authors	Hotz, Tazley A (A)   Kumar, Dhirendra D (A)
Affiliations:	(A): East Tennessee State University, Department of Biological Sciences

Salicylic acid (SA) plays an important role in defense responses against pathogens in plants. SA is lipid immobile and may not pass through the chloroplast membranes to enter into the cytoplasm to mediate the disease resistance signaling. It has been recently suggested that SA synthesized in the chloroplast is converted into lipid mobile methyl salicylate (MeSA) by an enzyme, salicylic acid methyl transferase (SAMT). To investigate the role played by SAMT in SA-mediated disease resistance signaling, we examined the expression of SAMT in the response of resistant tobacco to tobacco mosaic virus (TMV). To compare SAMT expression, we also studied tobacco plants susceptible to TMV expression and a transgenic tobacco plant (NahG) which does not accumulate SA. Expression studies were performed using semi-quantitative RT-PCR. To investigate the role of SAMT in plant immunity, we are in the process of making transgenic tobacco by either over expressing SAMT or by knocking out its expression using RNAi. These transgenic lines will be used to determine the role of SAMT in plant defense signaling. Understanding the biochemical pathways involved in plant defense response against pathogens will help to develop crop plants showing better resistance to ever-evolving pathogens.