Glutamate potentiates rice resistance to blast

Abstract

Leaf blast, caused by the hemibiotrophic fungus Pyricularia oryzae, is the most important disease affecting rice production worldwide. The present study investigated the potential of using glutamate (Glu) to increase rice resistance to leaf blast. Rice plants (cultivar Metica-1) were non-supplied (−Glu) or supplied (10 mM) (+Glu) with Glu and non-inoculated or inoculated with P. oryzae. Leaf blast severity and the number of lesions per cm2 of leaf were significantly lower by 55 and 50%, respectively, for +Glu plants in comparison to -Glu plants at 96 h after inoculation (hai). The area under the leaf blast progress curve was significantly lower by 70% for +Glu plants in comparison to -Glu plants. For inoculated +Glu plants, the activities of chitinase, β-1-3-glucanase, phenylalanine ammonia-lyase, and polyphenoloxidases as well as the concentrations of total soluble phenolics and lignin-thioglycolic acid derivatives were significantly higher for inoculated +Glu plants in comparison to inoculated -Glu ones. The use of glutamate may become an alternative to be used in the management of rice blast in the context of a sustainable agriculture.