|ZHAO, HAIJUN - Former ARS Employee|
|WANG, XUEYAN - University Of Arkansas|
|MINKENBERG, BASTIAN - Pennsylvania State University|
|WHEATLEY, MATHEW - Pennsylvania State University|
|FAN, JIANGBO - The Ohio State University|
|FAMOSO, ADAM - Louisiana State University|
|WAMISHE, YESHI - University Of Arkansas|
|VALENT, BARBARA - Kansas State University|
|WANT, GUO-LIANG - The Ohio State University|
|YANG, YIONG - Pennsylvania State University|
Submitted to: Plant and Animal Genome Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/27/2018
Publication Date: 1/12/2019
Citation: Jia, Y., Zhao, H., Wang, X., Minkenberg, B., Wheatley, M., Fan, J., Jia, M.H., Famoso, A., Edwards, J., Wamishe, Y., Valent, B., Want, G., Yang, Y. 2019. Functional characterization of a new class of rice blast resistance gene Ptr. Plant and Animal Genome Conference.
Technical Abstract: Plant genes that confer resistance to pathogens such as the rice blast pathogen, Magnaporthe oryzae, typically encode nucleotide binding sites -leucine rich repeat (NLR)-type receptor proteins. Rice blast resistance (R) genes Pi-ta and Pi-ta2 located near the centromere of chromosome 12 have been effectively deployed to prevent infections by M. oryzae for years. The Ptr gene was mapped within a 63 kilobase region on chromosome 12 using 11,618 segregating progenies derived from the cross of the Pita containing rice variety Katy with a susceptible rice variety Amane. The Ptr gene is located 211 kilobase away from the NLR R gene Pi-ta and another uncharacterized gene, Pi-ta2. Genetic analysis showed that Ptr confers broad spectrum disease resistance independent of Pi-ta. The Ptr gene encodes two predicted proteins that were mainly localized in the cytoplasm of plant cells. A two-base pair deletion within the Ptr coding region found in the fast neutron-created mutant line, M2354, produced a truncated protein, resulting in susceptibility to M. oryzae. Targeted mutation of Ptr in a resistant cultivar using CRISPR/Cas9 led to blast susceptibility, further validating its resistance function. The Ptr gene was predicted to encode a protein with four Armadillo repeats. DNA sequence analysis of 3000 rice accessions identified regions of high variability in Ptr suggesting that these regions may be involved in protein-protein interaction in triggering effective resistance. A new haplotype of Ptr was identified from a black hull awned weedy red rice (PtrBHA), and genetic analysis showed that PtrBHA is responsible for preventing the infections by a highly virulent blast race IB33. Weedy red rice is known to be compete with commercial rice, and functional validation of PtrBHA will shed more insights into adaptive immunity in rice. This knowledge is important to develop effective strategies to manage blast disease.