Characterization of mTERF family in allotetraploid peanut and their expression levels in response to dehydration stress

Abstract

Polyploidization events are prevalent in plants and act as an important evolutionary force for speciation, adaptation and diversification. During this process, the genome undergoes reorganization and large changes. However, the evolutionary characteristics of specific gene families are still not well investigated. Cultivated peanut is an allotetraploid that evolved from a diploid. In this study, we focused on the family of mitochondrial transcription termination factors (mTERF), which is increasing in gene number in higher plants and acts in organellar gene expression. The 65 mTERFs were identified in allotetraploid peanut, but only 31 in diploid peanut, which showed that the genome has not doubled simply during the polyploidization event. Some of the mTERFs may have emerged as a result of reverse complements, deletions, insertions, fusions and so on. mTERFs were divided into three groups according to their predicted localization. Six representative proteins showed their different localization. Most of the AhmTERF mRNAs were detected in root and leaf samples and responded to dehydration stress. Our data provide insights into the evolution of the mTERF gene family in peanut and further support the hypothesis that these genes respond to dehydration stress.