Mining novel seedling stripe rust resistance from Vavilov's wheat landraces using conventional and modern genetic tools
Wheat is one of the most important staple food and agricultural crop cultivated worldwide. To meet the demands of the raising human population, global wheat production has to be increased which is however declined due to appearance of highly virulent strains of Puccinia striiformis f. sp. tritici (Pst) fungus causing stripe rust disease. Globally, the incidence of stripe rust is effectively managed through the deployment of host plant mediated genetic resistance. But as the resistance present in the current wheat cultivars are ineffective, new sources of resistance particularly from pathogen unexposed genetic resources are of urgent need to prevent stripe rust epidemics. Landrace collections with rich genetic diversity and being less exposed to prevalent pathogen are of valuable source for resistance to new pathogens. In this study, a total of 295 landrace accessions collected by the famous Russian botanist Vavilov was screened for stripe rust resistance using the two predominant lineage Pst strains of Australia. Six accessions with good resistance against the two aggressive Pst strains were selected for genetic characterization and for utilization in global wheat breeding. Characterisation of these novel resistance were undertaken using combination of conventional and advanced genetic tools. While the conventional approach involves the traditional map based gene cloning, the other tool is the recently identified rapid method based on mutagenesis, targeted gene capture and next generation sequencing called "MutRenSeq". Subsequently, the identified novel resistant traits were transferred into elite wheat cultivars through the combination of linked molecular markers and speed breeding techniques. Thus along with the identification of novel resistance, elite wheat cultivars with broad spectrum stripe rust resistance were also generated through the use state of art techniques to sustain global wheat production from the rapidly evolving stripe pathogens.