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United States Department of Agriculture

Agricultural Research Service

Research Project: RESPONSE OF DIVERSE RICE GERMPLASM TO BIOTIC AND ABIOTIC STRESSES Title: Analysis of rice blast resistance gene Pi-z in rice germplasm using pathogenicity assays and DNA markers

Authors
item Roychowdhury, Moytri -
item Jia, Yulin
item Jackson, Aaron
item Jia, Melissa
item Fjellstrom, Robert
item Cartwright, Rick -

Submitted to: Euphytica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 13, 2011
Publication Date: February 13, 2012
Citation: RoyChowdhury, M., Jia, Y., Jackson, A.K., Jia, M.H., Fjellstrom, R.G., Cartwright, R. 2012. Analysis of rice blast resistance gene Pi-z in rice germplasm using pathogenicity assays and DNA markers. Euphytica. 184:35-46.

Interpretive Summary: Blast resistance gene Pi-z(t) in rice confers resistance to a wide range of races of the rice blast fungus, Magnaporthe oryzae. We surveyed 117 selected rice germplasm accessions using DNA markers and pathogenicity assays. The existence of Pi-z(t) in rice germplasm was detected by using four simple sequence repeat (SSR) markers (RM527, AP4791, AP5659-1, AP5659-5) closely linked to Pi-z(t) , and was verified using pathogenicity assays with an avirulent strain (IE1k) and two virulent races (IB33 and IB49). Among 117 germplasm accessions evaluated, 81 were found to be present the Pi-z(t) gene using both SSR markers and pathogenicity assays. The remaining 36 germplasm accessions were found to be different in their responses to the blast races IB33, IEIk and IB49, suggesting the presence of unexpected SSR alleles and additional Pi-z(t) independent R gene(s). This study demonstrated the power of resistance gene identification and verification using DNA markers and pathogenicity assays. These characterized germplasm can be used for genetic studies and marker-assisted breeding for improving blast resistance in rice.

Technical Abstract: The Pi-z(t) gene in rice confers resistance to a wide range of races of the rice blast fungus, Magnaporthe oryzae. The objective of this study was to characterize Pi-z(t) in 117 rice germplasm accessions using DNA markers and pathogenicity assays. The existence of Pi-z(t) in rice germplasm was detected by using four simple sequence repeat (SSR) markers (RM527, AP4791, AP5659-1, AP5659-5) closely linked to Pi-z(t) , and was verified using pathogenicity assays with an avirulent strain (IE1k) and two virulent races (IB33 and IB49). Among 117 germplasm accessions evaluated, 81 were found to be present the Pi-z(t) gene using both SSR markers and pathogenicity assays. The remaining 36 germplasm accessions were found to be different in their responses to the blast races IB33, IEIk and IB49, suggesting the presence of unexpected SSR alleles and additional Pi-z(t) independent R gene(s). These characterized germplasm can be used for genetic studies and marker-assisted breeding for improving blast resistance in rice.

Last Modified: 10/22/2014
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