Analysis on Blast Fungus-Responsive Characters of a Flavonoid Phytoalexin Sakuranetin; Accumulation in Infected Rice Leaves, Antifungal Activity and Detoxification by Fungus
Open Access
- 4 August 2014
- Vol. 19 (8), 11404-11418
- https://doi.org/10.3390/molecules190811404
Abstract
To understand the role of the rice flavonoid phytoalexin (PA) sakuranetin for blast resistance, the fungus-responsive characteristics were studied. Young rice leaves in a resistant line exhibited hypersensitive reaction (HR) within 3 days post inoculation (dpi) of a spore suspension, and an increase in sakuranetin was detected at 3 dpi, increasing to 4-fold at 4 dpi. In the susceptible line, increased sakuranetin was detected at 4 dpi, but not at 3 dpi, by which a large fungus mass has accumulated without HR. Induced expression of a PA biosynthesis gene OsNOMT for naringenin 7-O-methyltransferase was found before accumulation of sakuranetin in both cultivars. The antifungal activity of sakuranetin was considerably higher than that of the major rice diterpenoid PA momilactone A in vitro and in vivo under similar experimental conditions. The decrease and detoxification of sakuranetin were detected in both solid and liquid mycelium cultures, and they took place slower than those of momilactone A. Estimated local concentration of sakuranetin at HR lesions was thought to be effective for fungus restriction, while that at enlarged lesions in susceptible rice was insufficient. These results indicate possible involvement of sakuranetin in blast resistance and its specific relation to blast fungus.Keywords
This publication has 23 references indexed in Scilit:
- Biosynthesis, elicitation and roles of monocot terpenoid phytoalexinsThe Plant Journal, 2014
- Modulation of Phytoalexin Biosynthesis in Engineered Plants for Disease ResistanceInternational Journal of Molecular Sciences, 2013
- Identification of a Novel Casbane-Type Diterpene Phytoalexin, ent-10-Oxodepressin, from Rice LeavesBioscience, Biotechnology, and Biochemistry, 2013
- Phytoalexin transgenics in crop protection—Fairy tale with a happy end?Plant Science, 2012
- Phytoalexin Accumulation in the Interaction Between Rice and the Blast FungusMolecular Plant-Microbe Interactions®, 2010
- Contribution of Ethylene Biosynthesis for Resistance to Blast Fungus Infection in Young Rice PlantsPlant Physiology, 2006
- Metabolism and detoxification of phytoalexins and analogs by phytopathogenic fungiPhytochemistry, 2005
- Differences in phytoalexin response among rice cultivars of different resistance to blastPhytochemistry, 1997
- Phytoalexins, Stress Metabolism, and Disease Resistance in PlantsAnnual Review of Phytopathology, 1995
- Sakuranetin, a flavanone phytoalexin from ultraviolet-irradiated rice leavesPhytochemistry, 1992