Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress

Authors: HARRIS, M - North Dakota State University; Friesen, Timothy; Xu, Steven; Chen, Ming-Shun; GIRON, D - National Council For Scientific Research-Cnrs; STUART, J - Purdue University

Submitted to: Journal of Experimental Botany
Publication Type: Review Article
Publication Acceptance Date: 10/22/2014
Publication Date: 12/11/2014
Publication URL: http://handle.nal.usda.gov/10113/60155
Citation: Harris, M.O., Friesen, T.L., Xu, S.S., Chen, M.S., Giron, D., Stuart, J.J. 2015. Pivoting from Arabidopsis to wheat to understand how agricultural plants integrate responses to biotic stress. Journal of Experimental Botany. 66(2):513-531.

Interpretive Summary: The aim of this paper is to begin a conversation between the disparate communities of plant pathology and entomology as well as to understand how responses to biotic stress are integrated in an important crop. Parasites produce "effector" molecules that aid in gaining nutrients from the plant. These effectors are often times recognized by the plant surveillance system resulting in effector triggered immunity. Insects are responsible for a significant proportion of plant biotic stress but have not been fully integrated into plant pathology’s models of plant immunity. One reason for this has been an absence of molecular evidence that insects produce effectors that are recognized by plants. Thirty years after this evidence was discovered in a plant pathogen, there is now evidence for insects with the cloning of the Hessian fly's vH13 Avirulence gene. We review two models from plant pathology and discuss how insects could be included. We also review features that make wheat an interesting system for studying biotic stress, including 479 resistance genes known from agriculture that target viruses, bacteria, fungi, nematodes, insects, and mites. Genome sequencing of wheat is improving its tractability as an experimental system.

Technical Abstract: Here we argue for a research initiative on gene-for-gene (g-f-g) interactions between wheat and its parasites. One aim is to begin a conversation between the disparate communities of plant pathology and entomology. Another is to understand how responses to biotic stress are integrated in an important crop. The parasite's side of the g-f-g interaction is an Avirulence (Avr) gene that encodes one of the many effector proteins the parasite applies to the plant to assist with colonization. The plant's side is a Resistance (R) gene that mediates a surveillance system that detects the Avr protein and triggers effector-triggered plant immunity. Insects are responsible for a significant proportion of plant biotic stress but have not been fully integrated into plant pathology's models of plant immunity, where g-f-g interactions play an important role. One reason has been an absence of molecular evidence that insects interact with plants in a g-f-g manner. Thirty years after this evidence was discovered in a plant pathogen, there is now evidence for insects with the cloning of the Hessian fly's vH13 Avirulence gene. We review two models from plant pathology and discuss how insects could be included. We also review features that make wheat an interesting system for studying biotic stress, including 479 resistance genes known from agriculture that target viruses, bacteria, fungi, nematodes, insects, and mites. Many of these parasites show g-f-g interactions and are likely to use an effector-based strategy of attack. Genome sequencing of wheat is improving its tractability as an experimental system.