Genome-wide bioinformatic analysis of MYB gene family in monocotyledons and dicotyledons

The MYB transcription factor superfamily has a fundamental role in plant growth and development, activation of stress-responsive genes, and in some cases biosynthesis of key metabolites. The availability of potato, Arabidopsis (dicotyledonous), maize and barley (monocotyledonous) genome sequences provided the opportunity to identify 121, 139, 190 and 144 non-redundant MYB genes in these linages, respectively. In the study of the evolutionary characteristics of MYB conserved domains in two monocotyledonous plants, corn and barley, they were remarkably similar to each other in terms of alignment and order of placement. This characteristic was also true in relation to two dicotyledonous plants, potato and Arabidopsis, but the difference between MYB conserved domains in monocots and dicots was significant. In other words, it seems that despite the similarity of MYB genes in monocots and dicots, this gene family in the evolution in monocots and dicots have derived from each other. The 2R-MYB members were the most common subgroup of the MYB family in monocots and dicots and only one member of the 4R-MYB subfamily was observed in maize. In all four plants, the main reason for the functional differentiation of genes in this gene family was segmental duplication that has led to positive and purifying evolutionary selection. MYB gene family was located on all chromosomes of potato, Arabidopsis, maize and barley with non-uniform distribution. The expression pattern of AT1G57560, AT2G47190, AT3G23250 and AT1G56650 genes changed in more than one test of abiotic stress and hormonal response. Also, the expression pattern of AT1G74080, AT4G12350, AT4G22680, AT2G47190, AT1G48000, AT2G39880, AT5G40330 and AT5G16600 genes changed in more than one biotic stress test. On the other hand, the expression pattern of the AT2G47190 gene showed increased expression in several biotic and abiotic stresses. The presence of diverse and numerous regulatory Cis elements in response to stresses and hormones in the promoter region of MYB genes and the investigation of the expression profiles of this gene family in biotic and abiotic stresses in Arabidopsis indicates the functional diversity of the genes of this superfamily. In silico investigation of MYB gene superfamily in monocots and dicots provides a framework for comparative, evolutionary and functional studies of the members of this important gene superfamily.