Biotic interactions - Genomic approaches to interactions of plants with pathogens and symbionts

摘要

During the life span of a plant it will encounter interactions with a plethora of both beneficial and harmful organisms. The ability of plants to perceive, integrate and exchange molecular signals with these organisms has shaped the co-evolution of these interacting partners. Thus, plants have evolved sophisticated molecular mechanisms to respond to and to communicate with interacting organisms in their environment at both the molecular and cellular levels. This collection of reviews presents our current state of knowledge of the interactions of plants with pathogens and symbionts. The impact of molecular genetic analyses and genomic approaches has greatly affected the way in which we study these interactions. This has become most evident with the completion of the Arabidopsis genome and the sequencing of genomes of both pathogens and symbionts. Studies carried out in the past several years involving the cloning and characterization of plant disease resistance genes from both model and agronomically important crop plants have revealed that the majority of resistance genes identified to date contain NB/LRR (nucleotidebinding/leucine-rich repeat) motifs. However, the cloning of the RPM8 (RESISTANCE TO POWDERY MILDEW 8) gene from Arabidopsis demonstrates a new class of resistance genes and suggests that other classes may exist. The article by Jones (pp 281-287) summarizes our current state of knowledge in this area and emphasizes what lessons can be learned about disease resistance genes from sequencing the Arabidopsis genome. On the other hand, much has been revealed by studies of the well-characterized effector proteins of phytopathogenic bacteria. The article by Nimchuk et aL (pp 288-294) discusses the bifunctional nature of bacterial avirulence genes and the role that they play in both pathogen virulence and the specific induction of plant resistance responses.