Characteristics of the AT-Hook Motif Containing Nuclear Localized (AHL) Genes in Carrot Provides Insight into Their Role in Plant Growth and Storage Root Development.

Gabriela Machaj,Dariusz Grzebelus

doi:10.3390/genes12050764

Abstract

The AT-hook motif containing nuclear localized (AHL) gene family, controlling various developmental processes, is conserved in land plants. They comprise Plant and Prokaryote Conserved (PPC) domain and one or two AT-hook motifs. DcAHLc1 has been proposed as a candidate gene governing the formation of the carrot storage root. We identified and in-silico characterized carrot AHL proteins, performed phylogenetic analyses, investigated their expression profiles and constructed gene coexpression networks. We found 47 AHL genes in carrot and grouped them into two clades, A and B, comprising 29 and 18 genes, respectively. Within Clade-A, we distinguished three subclades, one of them grouping noncanonical AHLs differing in their structure (two PPC domains) and/or cellular localization (not nucleus). Coexpression network analysis attributed AHLs expressed in carrot roots into four of the 72 clusters, some of them showing a large number of interactions. Determination of expression profiles of AHL genes in various tissues and samples provided basis to hypothesize on their possible roles in the development of the carrot storage root. We identified a group of rapidly evolving noncanonical AHLs, possibly differing functionally from typical AHLs, as suggested by their expression profiles and their predicted cellular localization. We pointed at several AHLs likely involved in the development of the carrot storage root.

Highlights

The AT-hook motif containing nuclear localized (AHL) gene family is common and conserved in all land plants, suggesting that AHL genes are important for plant growth and development
Some AtAHL genes have been described as controlling hypocotyl growth and senescence [1,2,3], fertility and pollen development [4,5], root development [6] and flowering [7,8]
In subsequent analyses we included a gene (LOC108207572) which, according to results produced by InterProScan, encoded a protein with an incomplete Plant and Prokaryote Conserved (PPC)-domain and an AT-hook motif

Summary

Introduction

Some AtAHL genes have been described as controlling hypocotyl growth and senescence [1,2,3], fertility and pollen development [4,5], root development [6] and flowering [7,8]. They may be involved in the regulation of primary metabolism [9], hormonal homeostasis and signaling [10,11], drought tolerance [11] and pathogen defense [12]. Beside A. thaliana, an AHL gene was reported to be required for the development of maize ears [13]; depressed palea

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