Identification and fine mapping of Pi33, the rice resistance gene corresponding to the Magnaporthe grisea avirulence gene ACE1

Abstract

Rice blast disease is a major constraint for rice breeding. Nevertheless, the genetic basis of resistance remains poorly understood for most rice varieties, and new resistance genes remain to be identified. We identified the resistance gene corresponding to the cloned avirulence gene ACE1 using pairs of isogenic strains of Magnaporthe grisea differing only by their ACE1 allele. This resistance gene was mapped on the short arm of rice chromosome 8 using progenies from the crosses IR64 (resistant) x Azucena (susceptible) and Azucena x Bala (resistant). The isogenic strains also permitted the detection of this resistance gene in several rice varieties, including the differential isogenic line C101LAC. Allelism tests permitted us to distinguish this gene from two other resistance genes [ Pi11 and Pi-29(t)] that are present on the short arm of chromosome 8. Segregation analysis in F(2) populations was in agreement with the existence of a single dominant gene, designated as Pi33. Finally, Pi33 was finely mapped between two molecular markers of the rice genetic map that are separated by a distance of 1.6 cM. Detection of Pi33 in different semi-dwarf indica varieties indicated that this gene could originate from either one or a few varieties.

Screening of Rice Blast Resistance Genes from Aromatic Rice Germplasms with SNP Markers

“…Recently, more than 50 major blast resistance genes have been identified (Chauhan et al, 2002;Chen et al, 2002;Berruyer et al, 2003;Liu et al, 2004;Liu et al, 2005;Pan et al, 1999;Sallaud et al, 2003;Wu et al, 2003;Zhu et al, 2004). However, a number of blast resistance genes below have been mapped, which should be regarded as an essential starting point to isolate these important genes through map-based cloning approach.…”

The Rice Resistance Protein Pair RGA4/RGA5 Recognizes the Magnaporthe oryzae Effectors AVR-Pia and AVR1-CO39 by Direct Binding

“…Magnaporthe oryzae isolates and transgenic strains Guy11-AVR1-CO39 and Guy11-EV (Ribot et al, 2013) were grown on rice flour agar for spore production (Berruyer et al, 2003). For the determination of interaction phenotypes, a suspension of fungal conidiospores (5 3 10 4 spores$mL 21 ) was spray-inoculated on the leaves of 3-week-old plants (Berruyer et al, 2003).…”

“…For the determination of interaction phenotypes, a suspension of fungal conidiospores (5 3 10 4 spores$mL 21 ) was spray-inoculated on the leaves of 3-week-old plants (Berruyer et al, 2003). For gene expression analysis, an inoculum of 2 3 10 6 spores$mL 21 was used.…”

Analysis of simple sequence repeat markers linked with blast disease resistance genes in a segregating population of rice (Oryza sativa)

“…Several microsatellite markers with publicly available databases closely linked with the Pi-b, Pi-k h and Pi-ta 2 resistance genes have been identified (Fjellstrom et al, 2002). To date, more than 40 major blast resistance genes have been identified (Pan et al, 1999;Chauhan et al, 2002;Berruyer et al, 2003;Sallaud et al, 2003;Liu et al, 2004;Zhu et al, 2004). The presence of markers tightly linked to resistance genes will allow selection and maintenance of the desirable resistant genotypes in breeding process (Hittalmani et al, 1995;Naqvi and Chattoo, 1996).…”