Title : Defense mechanisms in multi-actor relationships: pathogenesis related gene response in agricultural important crops
Abstract:
Which are the main objectives of the study of the interactions between plants and pathogenic organisms? It’s possible to outline at least three: first of all, detailed analysis of plant-microbe interactions should provide sustainable solutions for the control of plant pests worldwide . Second, such study should help to identify the signaling mechanisms by which plant cells respond to biotic stresses. Last but not least, researchers, through the study of plant-pathogen interaction, may find out how organisms from different kingdoms communicate. Keys of this signaling pathways and communications are genes and proteins. Plant gene expression, infact, can be modified by various types of pathogens and parasites, including bacteria, fungi, viruses and nematodes; in literature, pathogenesis related (PR) genes are well known as inducible genes at the onset of biotic challenges and their role is to encode proteins which participate in the complex mechanisms of defense. New PR genes were identified and sequenced in Apulian accessions of leguminous plants. Moreover, an analysis of PR-gene expression patterns by qRT-PCR and the determination of nematode infection levels were carried out after that tomato (Solanum lycopersicon L) plants, phytoparasitic nematodes (Meloidogyne spp.) and symbiont fungi (Trichoderma spp.) were allowed to interact. Such a study has contributed to understand the role of Systemic Acquired Resistance (SAR) and Induced Systemic Resistance (ISR) in this multi-actor relationship.
In the presentation, three different interactions will be analyzed: plant-nematode, plant-fungi and plant–nematode-fungi to better understand the relationships between these common soil organisms. Successful pathogen infection occurs only if environmental conditions are favorable, if the preformed plant defenses are inadequate, and if either the plants fails to detect the pathogen or the activated defense responses are ineffective.
The major plant defense pathways adopted by tomato plants would be described along with the signal molecules and the genes induced by SAR or ISR. New pathogenesis related genes encoding for PR proteins in Apulian accessions of leguminous plants were identified, cloned and sequenced; the sequences are being deposited in NCBI gene bank and should be useful to extend the investigations from horticultural to those leguminous species that are becoming more and more important as source of proteins in humans and animals diets.
