Phylogenetic tree derived from Pi2/9 homologs in Brachypodium, sorghum and 14 rice lines. The Arabidopsis gene At3g07040.1 was used as an out group. Pi2/9 homologs from the same rice line were indicated with the same color. The sequences of the Pi2/9 loci from two cultivars (75-1-127, C101A51) and four wild rice species (O. nivar, O. punctata, O. minuta, and O. officinalis) were designated based on Qu et al., Zhou et al. and Dai et al. [18–20]. Pi2/9 gene family members from lines, PA64, NK58, MH63, SH527, GLA4 and IR24, were designated Pi2/9 followed by two suffixes separated by a hyphen. The first suffix identified the abbreviation of the cultivar or species designation, while the other numeric suffix represented the member’s order within the cluster. For the NBS-LRR genes in the wild rice species, additional suffixes denoting the sub genome designation were specified.