Author(s): MORALES, A.; O'ROURKE, J. A.; BORÉM, A.; ABDELNOOR, R. V.; PEDLEY, K. F.; WHITHAM, S. A.; GRAHAM, M. A.

Summary: Six Asian Soybean Rust (ASR) resistance loci have been identified and mapped in soybean genome: Rpp1 (Resistance to Phakopsora pachyrhizi 1), Rpp2, Rpp3, Rpp4, Rpp5 and Rpp6. Of particular interest is Rpp4, which has remained stable and confers resistance against Phakopsora pachyrhizi isolates from around the world. Sequencing of the region harboring Rpp4 in the susceptible cultivar Williams 82 (Wm82) and the resistant cultivar (PI459025B) genotype identified a cluster of CC-NBS-LRR resistance genes. Meyers et al. (2009) developed Virus Induced Gene Silencing constructs from the LRR regions of the Wm82 Rpp4 candidate genes to confirm that orthologous genes were responsible for resistance in the resistant parent (PI459025B). In this study, RNA samples extracted from the same Rpp4 LRR silenced and empty vector treated plants, also infected with P. pachyrhizi (described by Meyer et al., 2009) were compared using the GeneChip® Soybean Genome Array (Affymetrix®). Since the plant samples differed only in the expression of Rpp4, comparisons of these samples would identify genes downstream of Rpp4 in the signaling pathway. In total, 383 differentially expressed probes were identified, many with functions related to defense. While the time point analyzed was late in defense signaling, bioinformatic approaches were useful in characterizing the defense response and identify transcription factors regulating the response.

Publication year: 2012

Types of publication: Abstract in annals or event proceedings

Unit: Embrapa Soybean

Keywords: Doença de planta, Ferrugem, Phakopsora Pachyrhizi, Plant diseases and disorders, Rust diseases, Soja, Soybeans