Rmg7, a New Gene for Resistance to Triticum Isolates of Pyricularia oryzae Identified in Tetraploid Wheat

Abstract

A single gene for resistance, designated Rmg7 (Resistance to Magnaporthe grisea 7), was identified in a tetraploid wheat accession, St24 (Triticum dicoccum, KU120), against Br48, a Triticum isolate of Pyricularia oryzae. Two other wheat accessions, St17 (T. dicoccum, KU112) and St25 (T. dicoccum, KU122), were also resistant against Br48 and showed a similar disease reaction pattern to St24. Crosses between these resistant accessions yielded no susceptible F2 seedlings, suggesting that St24, St17, and St25 carry the same resistance gene. Furthermore, a single avirulence gene corresponding to Rmg7 was detected in a segregation analysis of random F1 progenies between Br48 and MZ5-1-6, an Eleusine isolate virulent to St24 at a higher temperature. This avirulence gene was recognized not only by St24, but also by St17 and St25, thus supporting the preceding results indicating that all three accessions carry Rmg7. This resistance gene may have potential in future wheat breeding programs.

Rmg8 and Rmg7, wheat genes for resistance to the wheat blast fungus, recognize the same avirulence gene AVR‐Rmg8

“…d), which contained a putative signal peptide, but showed no similarity to other known proteins in the database. Interestingly, T. dicoccum KU120 (St24) carrying Rmg7 (Tagle et al ., ) showed the same pattern of reactions to these transformants as S‐615 (Fig. ).…”

“…Recently, Tagle et al . () have identified a new resistance gene, Rmg7 , in tetraploid accessions. These accessions were resistant to the wheat blast fungus not only at the seedling stage, but also at the heading stage.…”

Variable resistance of bread wheat (Triticum aestivum) lines carrying 2NS/2AS translocation to wheat blast

“…Each spike was considered an experimental unit and a total of ten spikes (10 plants) were inoculated for each line. The disease evaluations were made 15 days after inoculations using a scale adapted from Tagle, Chuma, and Tosa (), as shown in Figure . The disease inoculations were repeated twice in the experiment, to verify the infection scores of the blast.…”

Patogenicidad de Magnaporthe oryzae en variedades y líneas de trigo cultivadas en Paraguay

“…La observación de síntomas y evaluación se realizó 15 días después de la inoculación. Se evaluó la severidad de la infección en las espigas, adaptando la escala propuesta por Tagle et al (2014). Esta escala clasifica los síntomas de la siguiente manera: 0 = Sin infección; 1 = Lesiones pequeñas, < 1.5 mm; 2 = Lesiones de tamaño intermedio, < 3 mm; 3 = and sterile distilled water (Marangoni et al, 2013).…”

“…Symptoms were observed and evaluated 15 days after inoculation. The scale proposed by Tagle et al (2014) was adapted to evaluate infection severity on the spikes. This scale classifies symptoms as follows: 0 = no infection; 1 = small lesions, < 1.5 mm; 2 = intermediate lesions, < 3 mm; 3 = mixture of green and white glumes, without apparent necrosis, caused by a hypersensitive reaction; 4 = complete spike necrosis.…”