Resistance (R) genes have a proven record for protecting plants against biotic stress. A problem is parasite adaptation via Avirulence (Avr) mutations, which allows the parasite to colonize the R gene plant. Scientists hope to make R genes more durable by stacking them in a single cultivar. However, stacking assumes that R gene-mediated resistance has no fitness cost for the plant. We tested this assumption for wheat's resistance to Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae). Our study included ten plant fitness measures and four wheat genotypes, one susceptible, and three expressing either the H6, H9, or H13 resistance gene. Because R gene-mediated resistance has two components, we measured two types of costs: the cost of the constitutively-expressed H gene, which functions in plant surveillance, and the cost of the downstream induced responses, which were triggered by Hessian fly larvae rather than a chemical elicitor. For the constitutively expressed H gene, some measures indicated costs, but a greater number of measures indicated benefits of simply expressing the H gene. For the induced resistance, instead of costs, resistant plants showed benefits of being attacked. Resistant plants were more likely to survive attack than susceptible plants, and surviving resistant plants produced higher yield and quality. We discuss why resistance to the Hessian fly has little or no cost and propose that tolerance is important, with compensatory growth occurring after H gene-mediated resistance kills the larva. We end with a caution: Given that plants were given good growing conditions, fitness costs may be found under conditions of greater biotic or abiotic stress.
How to translate text using browser tools
1 August 2011
No Fitness Cost for Wheat's H Gene-Mediated Resistance to Hessian Fly (Diptera: Cecidomyiidae)
Kirk M. Anderson,
Qing Kang,
John Reber,
Marion O. Harris
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
Journal of Economic Entomology
Vol. 104 • No. 4
August 2011
Vol. 104 • No. 4
August 2011
avirulence gene
Coevolution
Mayetiola destructor
plant breeding
pyramiding