Management of rust diseases in wheat and barley: Next generation tools

Abstract

The rust diseases are the destructive diseases of cereal crops. Development of host resistance is an effective means of managing these diseases. Adequate understanding of plant pathogen interactions will facilitate speeding up breeding for disease resistance in plants. Recent advancements in molecular biology and biotechnology have provided molecular tools which facilitate designing novel strategies for developing resistance in crop plants. Strategies based on transgenic and genomics approaches can be deployed for understanding the disease resistance mechanisms and development of resistant cultivars. Transgenic expression of antimicrobial peptides, enzymes that synthesize antifungal metabolites, growth inhibitors, proteins that inhibit fungal virulence proteins, and proteins that induce natural plant defenses are produced in plants upon attack by the fungal pathogens. Besides, studies have shown that animal immunity can be engineered into plants to provide resistance against pathogens. Further, multiple or combination of R genes could be used to develop wheat transgenics with durable and broad spectrum resistance. Furthermore, introduction of non-host resistance (NHR) is another effective means of rust resistance and it needs exploration of molecular mechanisms controlling the NHR. RNAi- based host plant mediated/induced pathogen gene silencing (HIGS) is another strategy recently deployed to explore for fungal resistance. Genomic selection is a novel molecular breeding approach provides opportunity for manipulation of complex traits like yield, drought tolerance, and disease resistance. Very recently, in vivo genome editing tools like the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas facilitate precise manipulation of genomes and understanding of disease resistance mechanisms and development of resistant cultivars. Apart from enhancing host plant resistance, other disease management strategies such as integrated disease management (IDM), disease epidemics prediction system, use of new generation fungicides with novel mode of action and nanotechnology based diagnostic devices are also critical for strategic management of diseases.