Role of Three Small Cysteine-Rich Proteins from Trichoderma virens as Elicitors of Plant Resistance

Abstract

Role of Three Small Cysteine-Rich Proteins from Trichoderma virens as Elicitors of Plant Resistance. (May 2013)

Rachel Beger Department of Biology Texas A&M University Research Advisor: Dr. Charles Kenerley Department of Plant Pathology & Microbiology

Trichoderma virens, a symbiotic plant fungus has the characteristic of inducing systemic and local resistance in plants against plant pathogens and acting as a mycoparasite of pathogenic fungi. These traits have resulted in T. virens being used as a biocontrol agent for plant disease management. One mechanism of biocontrol is the direct attack of pathogen propagules. A second mechanism involves the induction of defense responses. The second mechanism is initiated by root colonization and secretion of small cysteine-rich proteins either on the root surface or upon ingress by T. virens. The plant then exhibits higher expression of defense responses and at a more rapid rate compared to untreated plants when inoculated with a pathogen. SM1 is one protein that has been determined to have elicitor activity.

This study will determine if three additional small, secreted proteins (similar to SM1) are capable of inducing plant systemic resistance to pathogens. Vectors have been constructed to disrupt and over-express the targeted genes and will be used to transform wild type Gv29-8. The mutant strains will be tested on their ability to protect the host against pathogen infection. Expression analysis of the three selected genes will be performed by dual confrontation with fungal pathogens.