Analysis of MBOAT family reveals the diversity of MBOAT1 amplification in Solanaceae

Genes containing an MBOAT (membrane-bound O-acyltransferase) domain form a large gene family in plants whose members play important roles in plant triacylglycerol biosynthesis. Among these genes, most belong to the MBOAT1 subfamily. Here we describe the identification and analysis of MBOAT genes in Solanaceae. Through data mining of four sequenced genomes of Solanaceae, we identified 52 MBOAT members. The MBOAT genes fell into four distinct groups, with MBOAT1 subfamily genes accounting for about half of the total number of genes. Several MBOAT1 genes were present in the genomes of hot pepper, tomato and potato, whereas only one was identified in Nicotiana benthamiana. Most of tomato MBOAT1 genes were localized in chromosomes in the form of clusters, which is the same in potato, indicating that the population of MBOAT1 members was mainly the result of tandem duplication. Some tomato MBOAT1 genes were not expressed, and all MBOAT1 genes were devoid of introns and were significantly shorter than other MBOAT members were. While average pairwise Ka/Ks values were significantly lower within the MBOAT1 subfamily, some MBOAT1 genes showed signs of positive selection