|Moldenhauer, Karen A|
Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/5/2010
Publication Date: 8/21/2010
Publication URL: www.ars.usda.gov/SP2UserFiles/ad_hoc/622505005thInternationalRiceBlastConference/program-for-web-0809.pdf
Citation: Jia, Y., Lin, M.J., Dai, Y., Costanzo, S., Lee, S., Rubinelli, F.G., Green, E.A., Jia, M.H., Mcclung, A.M., Fjellstrom, R.G., Correll, J.C., Roy-Chowdhury, M., Cartwright, R., Lee, F.N., Moldenhauer, K.K., Liu, G., Zhou, X.G., Wang, X., Wu, D., Rioux, R.A., Tavantzis, S., Xing, J., Yan, L., Singh, P. 2010. Development of strategies to manage rice blast disease in the USA. Symposium Proceedings. IV-P-62. Interpretive Summary:
Technical Abstract: Rice blast disease has been a serious threat to stable rice production in the southern USA. Blast disease has been causing yield losses for decades. Severity of blast epidemics has been always influenced by a combination of the following three factors: 1) rice cultivars deployed with different combination of major and minor resistance (R) genes, 2) weather conditions during rice growing stages, particularly high relative humidity before and during heading, and 3) race composition of field pathogen populations. In the USA, successful deployment of rice degree day known as “DD-50” program with improved varieties carrying both major and minor R genes has greatly contributed to the effectiveness of blast management. Since the fourth International Rice Blast Conference held in Changsha, the map positions, resistance spectra, DNA sequence variation, and evolution of the six most commonly used blast R genes, Pi-ta, Pi-b, Pi-kh/s(m), Pi42(t), Pi43(t), Pi-z(t) and eight blast resistant QTLs in the USA have been investigated. Progress will be presented by Costanzo, Lee, Dai, Roy-Chowdhury, Wang, Liu, and Zhou. Additional accomplishments are listed below: I. Through a combination of DNA sequencing, genetic crosses and pathogenicity assays a large linkage block at the Pi-ta region was identified. Genotyping of selected rice germplasm and six mapping populations revealed that such a linkage block is a result of the combination of selection of blast resistance, recombination suppression, and segregation distortions. II. Resistant spectrum of the Pi-ta gene in the USA was determined. The Pi-ta gene was found to confer resistance to 10 races of the US blast fungus. III. A total of 182 mono and digenic rice lines with different combinations of Pi-ta, Pi-kh and Pi-ks and agronomic traits have been created to facilitate the genetic studies of epistatic interactions of yield, yield components and blast resistance. References: 1. Jia, Y. 2009. Artificial introgression of a large chromosome fragment around the rice blast resistance gene Pi-ta in backcross progeny and several elite rice cultivars. Heredity 103: 333-339. 2. Jia, Y and Moldenhauer, KAK. 2010. Development of monogenic and digenic rice lines for blast resistance genes Pi-ta, Pi-kh/Pi-ks. Journal of Plant Registration 4: 163-166 (cover story). 3. Jia, Y., Lee, F., and McClung, A. 2009. Determination of resistance spectra to US races of Magnaporthe oryzae causing blast in a recombinant inbred line population. Plant Disease 93: 639-644.