Studies on host-selective infection mechanism of Pyricularia oryzae Cavara. (2). Production of susceptibility-inducing factor(s) from germinating spores and their phytotoxicity.

Fukuyama

Honda

2000

The effect of light irradiation on Sekiguchi lesion formation induced by infection with Bipolaris oryzae on rice sl mutants was investigated. Although the Sekiguchi lesions formed exclusively under daylight fluorescent lamps, brown spots and necrotic spot lesions formed in the dark. The Sekiguchi lesions were larger than the brown spot lesions. When leaf blades inoculated with B. oryzae were irradiated through band‐pass filters of BPB‐45, BPB‐50, BPB‐55, and BPB‐60, Sekiguchi lesions were formed regardless of the BPB filters' wavelengths. Under black‐light lamps, near‐infrared fluorescent lamps, or in the dark, however, brown spot lesions were induced by B. oryzae. The effective wavelength region for light‐dependent Sekiguchi lesion formation was 400–700 nm. Furthermore, there was a direct correlation between the length of the radiation wavelengths and the size of the Sekiguchi lesions.

Section: Discussionmentioning

confidence: 99%

Light‐Dependent Induction of Sekiguchi Lesion Formation by Bipolaris oryzae in Rice cv. Sekiguchi‐asahi

Fukuyama

Honda

2000

“…Keissler of the leaves of cv. Sekj guchi -asahi (ARASE et al 1990a). SGFs also caused a charac teri sti c necros is on the leaves of cv.…”

Section: Zusammenfassungmentioning

confidence: 96%

“…Some pathologically important prob lem s o f the rice and P. oryzae interaction h ave yet to be elucidated, esp ecially the mechanism for race specificity of P. oryzae to rice cultivars in pathogeni city and t he importance o f the disease d etermin ants, su ch as h ost-specific U. S. Copyri ght C lea rance Center Code Statement: 093 1-1785/94/4203-0245$ 10.50/0 FUJITA, ARASE, H IRATSUKA, H ONDA and N ozu toxin(s) (NISHIM URA andKOHMOTO 1983, SCHEFFER andYODER 1972) o r suppressors (O KU et al 1987).…”

Section: Zusammenfassungmentioning

confidence: 99%

The Role of Toxin(s) Produced by Germinating Spores of Pyricularia oryzae in Pathogenesis

Fujita

Hiratsuka

et al. 1994

Pyricularia oryzae produced toxin(s) during spore germination w hich induced susceptibility to infection by non-pathogeni c Alternaria alternata of rice leaves. The induced susceptibili ty was ind ependent of the co mpatibility between the races of blast fun gi used for obtaining th e toxin(s) and th e rice cu ltivars used for bioassay. Susceptibility was also induced in other susceptible species (e.g. barley, Italian ryegrass, perennial ryegrass and wheat), results suggestin g that th e toxin(s) are host-selective and determine the host specifi city at plant species level.

“…Sekiguchi-asahi (blast resistance Pi-a), was grown as described previously (Arase et al, 1990a). Magnaporthe grisea (Strain Naga 69±150, race 007) and Cladosporium paenoiae were used as the pathogen and assay fungus, respectively.…”

Section: Plant and Fungusmentioning

confidence: 99%

“…Magnaporthe grisea (Strain Naga 69±150, race 007) and Cladosporium paenoiae were used as the pathogen and assay fungus, respectively. Magnaporthe grisea spores were synchronously formed on an oatmeal medium as described previously (Arase et al, 1990a). Cladosporium paenoiae spores were formed by culturing on a potato sucrose agar (PSA) medium at 26°C for 14 days (Islam et al, 1999).…”

Section: Plant and Fungusmentioning

confidence: 99%

Light‐Dependent Accumulation of Tryptamine in the Rice Sekiguchi Lesion Mutant Infected with Magnaporthe grisea

Ueno

Toko

et al. 2001

An antifungal compound with an infection-inhibiting activity was isolated from a rice Sekiguchi lesion (sl) mutant and identi®ed as the indole alkaloid tryptamine. Tryptamine inhibited not only spore germination and appressorium formation of Magnaporthe grisea at high concentrations (> 600 lg/ml) but also the infection hypha formation in onion cells at low concentrations (150±300 lg/ml). Tryptamine is a normal compound of the rice sl-mutant but accumulates further in rice with a mutant-type response (Sekiguchi lesion formation) to inoculation with M. grisea spores. A mutant type of response is involved in light-enhanced resistance. The accumulation of tryptamine was not induced, however, in rice with a wild-type response (blast lesion formation). This study strongly suggests that tryptamine plays an important role as a possible factor in light-enhanced resistance in the rice sl-mutants.