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Title: Rooting out Defense Mechanisms in Wheat against Plant Parasitic Nematodes

item THOMPSON, ALISON - Washington State University
item Campbell, Kimberly
item Paulitz, Timothy
item SMILEY, RICHARD - Oregon State University

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/20/2014
Publication Date: 7/20/2014
Citation: Thompson, A., Campbell, K., Paulitz, T.C., Smiley, R. 2014. Rooting out Defense Mechanisms in Wheat against Plant Parasitic Nematodes. American Society of Plant Biologists Annual Meeting. P29039-C.

Interpretive Summary:

Technical Abstract: Root-lesion nematodes (Pratylenchus spp.) are soil borne pathogens of many important agricultural crops including wheat. Pratylenchus invade root cells and feed using a stylet, resulting in cell death. Common signs of Pratylenchus damage are root lesions, girdling, and lack of lateral branching. In the Pacific Northwest (PNW) P. neglectus and P. thornei were found in 95% of sampled fields and trials conducted in the same region estimate wheat yield loss between 37-50%. Resistance to Pratylenchus has been found in landrace wheat accessions from Iran which have been crossed into local PNW cultivars. The resistance mechanisms to Pratylenchus in wheat are poorly understood. Understanding how resistance works could increase breeding efficiency and resistance sustainability. Early observational studies show that, Louise a susceptible PNW-adapted spring wheat cultivar is readily penetrated by Pratylenchus, but that AUS28451 (PI623470), a resistant landrace accession, has little to no root penetration. Overtime Louise roots, in culture, develop multiple lesions and few lateral roots while AUS28451 does not appear affected. Further studies found that AUS28451 has a slow growing and expansive root system compared to Louise, suggesting increased cell wall composition. Florescence microscopy showed that AUS28451 appeared to have increased root lignin content compared to Louise. Lignin extractions using a thioglycolic acid precipitation method confirmed AUS28451 has more root lignin than Louise. This data indicates that increased root lignin content may be providing a physical barrier against Pratylenchus penetration of AUS28451 roots. Lignin is continuing to be investigated in a recombinant inbred mapping population derived from Louise and AUS28451 by mapping lignin associated loci and quantitative PCR of known lignin biosynthesis genes.