Pathogenic Races of Phakopsora pachyrhizi on Soybean and Wild Host Plants Collected in Japan

Abstract

A total of 46 single uredinial isolates of Phakopsora pachyrhizi were collected from rust-infected soybean and wild host plants (Pueraria lobata and G. soja) at different localities in central and southwestern Japan. Eighteen pathogenic races were identified using a set of differential varieties composed of nine cultivars of soybean and two accession lines of G. soja. Nine and 11 races were found on soybean and wild host plants, respectively. Two races were common to soybean and wild host plants.

New soybean (Glycine max Fabales, Fabaceae) sources of qualitative genetic resistance to Asian soybean rust caused by Phakopsora pachyrhizi (Uredinales, Phakopsoraceae)

“…The development of soybean cultivars resistant to ASR may prove complicated because monogenic resistance is unlikely to provide lasting protection due to the high genetic variability of P. pachyrhizi, several races of which have already been identified (Yamaoka et al, 2002;Miles et al, 2006). Some soybean genotypes initially identified as resistant to ASR have had this resistance broken, as has occurred with the genotypes carrying Rpp1 and Rpp3 when exposed to the P. pachyrhizi Taiwan-72-1 isolate (Hartwig, 1986) and to the new P. pachyrhizi isolate from the Brazilian state of Mato Grosso (MT, the Brazilian government abbreviation for this state), the P. pachyrhizi MT state isolate, described by Yorinori et al (2004).…”

Advances on molecular studies of the interaction soybean - Asian rust

“…Additionally, some alleles was mapped on the same chromosome, for exemple, Rpp1b was also mapped on Chr 18, while Rpp Hyuuga was also mapped on Chr 6 (Monteros et al 2007, Chakraborty et al 2009 Despite the physical location of the Rpp genes and the recent release of the soybean genome (Schmutz et al 2010), none of them was cloned yet. However, significant progress has been made towards cloning Rpp4, which remained the most stable gene when challenged against isolates of fungus from different parts of the world (Yamaoka et al 2002, Bonde et al 2006). Sequencing of the mapped region in the susceptible genotype Williams 82 identified a cluster of three resistance genes, CC-NBS-LRR (coiled-coil, nucleotidebinding site, leucine-rich repeats), within a 2cM region on chromosome 18, which shows sequence similarly to the lettuce RGC2 family of resistance genes (Meyer et al 2009).…”

Variabilidade genética de Phakopsora pachyrhizi avaliada por meio de marcadores microssatélites

“…Contudo, no ano seguinte, esta resistência foi quebrada. Essa cultivar apresenta o gene denominado Rpp (FT2) (Yamanaka et al, 2008) A variabilidade genética em populações de P. pachyrhizi tem sido relatada de acordo com a variabilidade na virulência do patógeno (Sinclair & Hartman, 1999;Yamaoka et al, 2002;Bonde et al, 2006) e por análise molecular de regiões ITS (Freire et al 2008). Anderson et al (2008) (Soares et al, 2008), o que mostra que há variabilidade na patogenicidade do fungo no Brasil.…”

“…Diversos trabalhos relatam a existência de variabilidade genética em populações de P. pachyrhizi (Sinclair & Hartman, 1999;Yamaoka et al, 2002;Bonde et al, 2006;Freire et al, 2008). As fontes identificadas de resistência, no entanto, são todas específicas a determinados isolados do fungo (Bonde et al, 2006).…”

“…As fontes identificadas de resistência, no entanto, são todas específicas a determinados isolados do fungo (Bonde et al, 2006). Yamaoka et al (2002) (Soares et al, 2009).…”