Nucleic acid encoding lipid transfer protein which exhibits SAR (systemic acquired resistance) by specific process

摘要

A nucleic acid molecule which encodes a lipid transfer protein wherein the encoded lipid transfer protein exhibits a SAR signal transducing property. The nucleic acid molecule is obtained by the steps of: a) growing wild type and T-DNA transformed plants and observing for disease symptoms; b) isolating SAR mutants showing disease symptoms; c) performing SAR competence tests to validate the SAR mutation in the SAR mutants, wherein the SAR is comprised in a SAR mutant plant upon first being treated on one leaf of the plant with an avirulent inoculum and later being treated on other leaves if the plant with virulent inoculum as compared to a wild type plant which exhibits SAR upon first being treated on one leaf with an avirulent inoculum and later being treated on other leaves with a virulent inoculum; d) testing the SAR mutants to determine the position of the mutant gene in relation to the point of salicylic acid action in the signal transduction pathway, wherein the SAR mutants which are first sprayed with substance that mimics salicylic acid and acts at about the same point as salicylic acid in the SAR signal transduction pathway, challenged with a virulent inoculum, and then remain symptomless exhibit a SAR mutant gene upstream of the point of salicylic acid action in the signal transduction pathway; e) isolating DNA from those plants which are homozygous for SAR mutant gene, and where the gene is found to encode a protein which acts upstream from the site of salicylic acid action alone the signal transduction pathway; and f) probing the DNA to isolate cDNA.