Wheat blast: a new threat to food security

Abstract

Wheat blast, caused by the Magnaporthe oryzae Triticum (MoT) lineage (synonym Pyricularia oryzae Triticum lineage), is a destructive disease in South America and Bangladesh. It is primarily a disease of wheat head, which can cause yield loss up to 100% under favorable disease conditions. The head infection results in complete or partial bleaching of the spike above the point of infection with either no grain or shriveled grain with low test weight. Due to low fungicide efficacy against the disease and lack of availability of resistant varieties, an integrated management program should be adopted to control this serious wheat disease. First of all, a convenient and specific diagnostic tool is needed for evaluating seed health and early detection in wheat field to initiate timely mitigation measures and thereby decreasing pathogen initial inoculum and dispersal. Second, we should have a better understanding of the epidemiology of the disease and develop a real-time disease monitoring and surveillance system to alert growers to apply management practices at an optimum time. Third, we need a better understanding of the infection biology of the fungus and its interaction with wheat plants at the tissue and molecular levels helpful for improving disease management. Fourth, breeding for resistance to wheat blast can be accelerated by using resistance genes such as 2NS translocation, Rmg8 and RmgGR119 or advanced genomic technology such as CRISPR-Cas. Fifth, integration of alternative disease management practices, such as biological control using antagonistic microorganisms or derivatives thereof to achieve sustainable approach for the management of wheat blast. Finally, a globally concerted effort is needed using open science and open data sharing approaches to prevent this seed- and air-borne plant disease’s widespread devastation of wheat crop. This comprehensive review updates our knowledge on wheat blast disease and discusses the approaches for its sustainable management for ensuring food and nutritional security of the ever-increasing global population.