Emerging and re-emerging viruses of wheat: current status and future challenges

New emerging viruses that are threatening the world's wheat production include wheat mosaic virus, barley yellow dwarf virus, wheat streak mosaic virus, and wheat spindle streak mosaic virus etc. The continuous occurrences of these viruses on wheat along with their spatio-temporal movement via infected wheat germplasm reported to cause heavy yield loss in different parts of the world. Significant research strides have been made in past several decades to understand the biology, ecology and epidemiology of the maladies imposed by these emergent viruses along with their vectors in wheat. Several potential sources imparting resistance against viruses and insect vectors have been identified in wide relatives of wheat. Recent genomic innovations have also expedited the application of molecular tools in speeding up the process of identification, isolation and cloning of resistance genes, in addition to offering additional advantages in terms of more precise detection of new and more efficient alleles and their genetic efficient deployment in enhancing resistance potentialities against emerging and reemerging viruses in wheat.