Genome-Wide Identification and Expression Analyses of Aquaporin Gene Family during Development and Abiotic Stress in Banana.

Wei Hu,Zhiqiang Jin,Juhua Liu,Zehong Ding,Yunxie Wei,Hongxia Miao,Chao Huang,Meiying Li,Weiwei Tie,Yan Yan,Biyu Xu,Xiaowan Hou,Zhiwei Lu

doi:10.3390/ijms160819728

Abstract

Aquaporins (AQPs) function to selectively control the flow of water and other small molecules through biological membranes, playing crucial roles in various biological processes. However, little information is available on the AQP gene family in bananas. In this study, we identified 47 banana AQP genes based on the banana genome sequence. Evolutionary analysis of AQPs from banana, Arabidopsis, poplar, and rice indicated that banana AQPs (MaAQPs) were clustered into four subfamilies. Conserved motif analysis showed that all banana AQPs contained the typical AQP-like or major intrinsic protein (MIP) domain. Gene structure analysis suggested the majority of MaAQPs had two to four introns with a highly specific number and length for each subfamily. Expression analysis of MaAQP genes during fruit development and postharvest ripening showed that some MaAQP genes exhibited high expression levels during these stages, indicating the involvement of MaAQP genes in banana fruit development and ripening. Additionally, some MaAQP genes showed strong induction after stress treatment and therefore, may represent potential candidates for improving banana resistance to abiotic stress. Taken together, this study identified some excellent tissue-specific, fruit development- and ripening-dependent, and abiotic stress-responsive candidate MaAQP genes, which could lay a solid foundation for genetic improvement of banana cultivars.

Highlights

Aquaporins (AQPs), belonging to the major intrinsic protein (MIP) superfamily, function to selectively control the flow of water and other small molecules, such as CO2, glycerol, and boron, through biological membranes [1,2,3,4,5]
Conserved domain and multiple sequence alignment analyses suggested that all identified banana AQPs contained the typical AQP family MIP domain
The results showed that all identified AQPs from banana were clearly divided into four different subfamilies (PIP, tonoplast intrinsic proteins (TIPs), nodulin 26-like intrinsic proteins (NIPs), and small basic intrinsic proteins (SIPs)), together with AQPs from Arabidopsis, poplar and rice

Summary

Introduction

Aquaporins (AQPs), belonging to the major intrinsic protein (MIP) superfamily, function to selectively control the flow of water and other small molecules, such as CO2, glycerol, and boron, through biological membranes [1,2,3,4,5]. There are highly conserved structures in plant AQPs, in which six membrane-spanning α-helices are linked by five short loops with their N- and C-termini always towards the cytosol [15]. Two of these loops (Loop B and E) contain highly conserved Asp-Pro-Ala (NPA) motifs which play a major role in the formation of water-selective channels [11]. Other important residues in aquaporin sequences are the ones forming the aromatic/arginine selectivity filter (ar/R). This region is formed by four residues towards the extracellular side approximately 8 Å from the NPA region. The ar/R region has been considered to serve as a selectivity filter for the transport of substrates, determine the transport rate of the protein by acting as a size-exclusion barrier, and provide key hydrogen bonds and van der Waals contacts for the transported solutes and/or water molecules [18]

Results

Discussion

Conclusion