Genome editing of PHS-associated AGO4_9 genes in small grain cereals

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Pre-Harvest Sprouting (PHS) is the germination of grains before harvest under hot and humid conditions. PHS greatly diminishes the economic value of the harvested grains and the annual cost of PHS globally to the wheat industry exceeds $1 billion. Recently, a loss of $100 million has been documented in Canada alone. Therefore, resistance to PHS is a highly desirable genetic trait for the wheat breeding programs in both the public sector and industry such as Corteva Agriscience. We recently discovered a key gene that acts as a switch to determine how a particular plant will respond to high humidity and excess rainfall by either germinating early (PHS) or not (http://www.mcgill.ca/channels/news/mcgill-discovery-should-save-wheat-farmers-millions-231037). This switch has been found in in the "RNA dependent DNA Methylation" pathway (Singh et al., 2013). We found that Argonaut genes, AGO4_9 class have been associated with pre-harvesting sprouting (PHS) in barley and wheat (Singh and Singh, 2012; Singh et al., 2013). The association of key gene (AGO4) of RNA-directed DNA methylation (RdDM) pathway with PHS in cereals indicating that AGO4 enhances DNA methylation and acts as a negative regulator of seed dormancy. This piece of research opens up a completely new area of exploration for plant scientists as they are endeavoring to increase the yields of cereals and minimize losses due to excessively humid conditions. The current project proposal aims to further understand the role of AGO4_9 in seed germination, dormancy and PHS in barley and wheat and assess their potential to develop novel PHS resistant breeding lines through CRISPR-based Genome Editing (GE) tools.