Genome-wide characterization of MLO family genes in bread wheat and Arabidopsis thaliana shed light on their role in growth and development, and resistance to powdery mildew, biotic and abiotic stresses

Abstract

Powdery mildew (PM), caused by the fungus, Blumeria graminis Bgt is a devastating and notorious disease that is prevalent across the globe and causes up to 62% of yield losses in wheat. The well-known 68 PM resistance loci are never long-lasting and break down when new races of pathogens interact with host plants. The editing of three known MLO genes through CRISPR/Cas9 has conferred resistance against PM. However, only 10 MLO genes were known in wheat to date. Taking advantage of IWGSC refseq v2.1 and using the gold-standard analysis pipeline that we have established, we expanded this number to 47 and reported 44 additional potential CRISPR targets that can be used to develop PM in wheat. We also performed phylogenetic, gene structure, Motif, and gene duplication, evolution, and comparative phylogenetic analysis with Arabidopsis thaliana and brachypodium distachyon to establish their evolutionary relationship; and finally, their expression under powdery mildew, rusts, head blight, abiotic stresses, and growth and development and predicted their potential roles in wheat under these conditions. We hope that the MLO genes identified in this study will be a great resource for the wheat community to develop PM resistance in wheat.