Submitted to: Journal of Plant Interactions
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/29/2021
Publication Date: 4/27/2021
Citation: Subramanyam, S.N., Nemacheck, J.A. 2021. Nonhost Kitaake rice displays phenotypic characteristics of host resistant wheat and molecular biomarkers of both resistant and susceptible wheat in response to feeding by Hessian fly larvae. Journal of Plant Interactions. 16(1):156-165. https://doi.org/10.1080/17429145.2021.1912421.
Interpretive Summary: Hessian fly is a devastating pest of modern-day bread wheat. Despite identification of several genes involved in wheat defense against Hessian fly, pinpointing their function/role is extremely challenging. This is because bread wheat is a complex hexaploid that has three different genomes (A, B and D). This problem can be overcome by using less complex model genomes. In this study we show that Kitaake rice plants, a model genome, exhibits nonhost resistance to Hessian fly attack and resembles the common bread wheat at the physical and molecular level. We demonstrate the usefulness of using rice plants as substitute genome to study genes identified from bread wheat, and further our understanding of wheat defense against this and other destructive insect pests.
Technical Abstract: The Hessian fly causes severe economic losses in host wheat. Despite identification of numerous Hessian fly-responsive genes, the genome complexity in hexaploid wheat makes their functional characterization extremely challenging. In this study, we have characterized phenotypic and molecular responses of the Kitaake rice cultivar, with a simpler genome, to infestation by Hessian fly. Our results reveal that Kitaake rice exhibits responses resembling nonhost resistance to Hessian fly. Larvae feeding on Kitaake rice do not develop beyond first instars, and infested plants show growth comparable to uninfested plants with restricted cell wall permeability, similar to resistant host wheat. However, the larvae show prolonged survival on Kitaake plants as first-instars beyond 7 days after hatch (DAH) unlike the nonhost Brachypodium plants, where some larvae develop into small, white, second-instars. Kitaake rice plants exhibit a molecular response similar to not only resistant but also susceptible host wheat for six Hessian fly-responsive biomarker genes assayed. However expression of genes encoding cell wall-associated proteins and secondary metabolite pathways are similar to those in resistant host wheat plants. Further, lectins and secondary metabolites may play an important role in early defense strategy of Kitaake rice preventing the larvae from developing beyond the first-instar developmental stage. The phenotypic and molecular characterization of Kitaake rice reveals its suitability as a surrogate model genome for undertaking downstream functional genomics studies of candidate wheat genes that respond to Hessian fly larval attack.