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ARS Home » Pacific West Area » Pullman, Washington » WHGQ » Research » Publications at this Location » Publication #409250
Research Project: Wheat and Barley Adaptation to a Changing Climate - Discovery of Genetic and Physiological Processes for Improved Crop Productivity and Quality

Location: Wheat Health, Genetics, and Quality Research

Title: Differential induction of defense genes in hexaploid wheat roots by the plant-parasitic nematodes Pratylenchus neglectus and P. thornei

Author
item Okubara, Patricia
item SHARPE, RICHARD - Washington State University
item Peetz, Amy
item Li, Xianran
item Zasada, Inga

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2024
Publication Date: 8/29/2024
Citation: Okubara, P.A., Sharpe, R., Peetz, A.B., Li, X., Zasada, I.A. 2024. Differential induction of defense genes in hexaploid wheat roots by the plant-parasitic nematodes Pratylenchus neglectus and P. thornei. PLOS ONE. 19(8): e0306533. https://doi.org/10.1371/journal.pone.0306533.
DOI: https://doi.org/10.1371/journal.pone.0306533

Interpretive Summary: Root lesion nematodes infest 60% of dryland wheat fields in the eastern Washington State and cause significant yield lost. The most effective way to control nematodes is the deployment of resistant varieties. Understanding how wheat plants respond to nematodes infection is critical for developing resistant plants. This study investigated the changes in root gene expression after infection with two species of root lesion nematode. The numbers of defense genes expressed in response to the nematodes and the magnitudes of gene expression suggest that resistance needs to be tailored to each nematode species. However, the study identified several gene regulators (promoters) that could be used to turn on defense gene expression against both species.

Technical Abstract: Pratylenchus neglectus and P. thornei are among the most destructive root lesion nematodes of wheat in the Pacific Northwest, USA and throughout the world. The aim of this study was to determine whether both nematode species were similar in their ability to induce defense genes in a susceptible wheat cultivar, and whether a combination of both species had a different pattern of gene induction than each species alone. The long-term aspect of the research was to identify nematode-inducible promoters for deploying defense genes in roots. The root transcriptomes of the susceptible hexaploid wheat cultivar Scarlet were obtained after a one-week infection period with each nematode species separately, or both species combined. Root defense gene expression was induced for all three treatments relative to the no-nematode control, but P. thornei affected expression to a greater extent compared to P. neglectus. The species combination induced the highest number of defense genes. This result was not predicted from nematode enumeration studies, in which P. thornei colonization was substantially lower than that of P. neglectus, and the nematode combination did not show a significant difference Quantitative real time polymerase chain reaction (qRT-PCR) assays for Dehydrin, Glucan endo-1,3-beta-glucosidase, 1-cys-Peroxiredoxin, Pathogenesis-related protein 1 and Late embryogenesis-abundant proteins 76 and group 3 authenticated the induction observed in the transcriptome data. In addition, a near-isogenic line of Scarlet harboring genetic resistance to fungal soilborne pathogens, called Scarlet-Rz1, showed similar or higher levels of defense gene expression compared to susceptible Scarlet in qRT-PCR assays. Gene ID annotations that were mapped using a wheat coding sequence database differed somewhat from those obtained using the wheat genome, but defense gene induction in both databases were very similar. Finally, defense gene expression patterns revealed nematode-inducible promoters that are responsive to both P. neglectus and P. thornei.