Identification and expression analysis of multiple FRO gene copies in Medicago truncatula

Abstract

ABSTRACT. Iron (Fe) is an essential element for plant growth. Commonly, this element is found in an oxidized form in soil, which is poorly available for plants. Therefore, plants have evolved ferric-chelate reductase enzymes (FRO) to reduce iron into a more soluble ferrous form. Fe scarcity in plants induce the FRO enzyme activity. Although the legume Medicago truncatula has been employed as a model for FRO activity studies, only one copy of the M. truncatula MtFRO1 gene has been characterized so far. In this study, we identified multiple gene copies of the MtFRO gene in the genome of M. truncatula by an in silico search, using BLAST analysis in the database of the M. truncatula Genome Sequencing Project and the National Center for Biotechnology Information, and also determined whether they are functional. We identified five genes apart from MtFRO1, which had been already characterized. All of the MtFRO genes exhibited high identity with homologous FRO genes from Lycopersicon esculentum, Citrus junos and Arabidopsis thaliana. The gene copies also presented characteristic conserved FAD and NADPH motifs, transmembrane regions and oxidoreductase signature motifs. We also detected expression in five of the putative MtFRO sequences by semiquantitative RT-PCR analysis,

Identification and Expression Analysis of Multiple Ferric Chelate Reductases in Citrus junos

“…Subsequently, seven other functional members of the same family have been identified in the model plant arabidopsis (Mukherjee et al, 2006;Wu et al, 2005). Similarly, six MtFROs were reported for M. truncatula (Orozco-Mosqueda et al, 2012) and five CjFROs for C. junos in our experiment. The reason why plants contain multiple FRO genes in their genomes has already been summarized in excellent reviews: FROs are well known for their role in iron uptake by roots and furthermore, may play critical roles in the iron uptake by leaves as well as for iron homeostasis in chloroplasts and mitochondria (Jain et al, 2014;Jeong and Connolly, 2009).…”

“…Online plant genomics offer greatly valuable databases for the identification and further characterization of genes that are involved in diverse cellular processes, such as Fe-starvation responses. Eight FROs had been found in the A. thialiana genome and six FROs in the M. truncatula according their genomic databases (Orozco-Mosqueda et al, 2012;Wu et al, 2005). Just like A. thialiana and M. truncatula, C. junos belongs to the plants using strategy I for Fe acquisition, which can reduce rhizospheric iron, thus increasing the bioavailability of iron.…”

“…The first FRO gene was identified in the model plant Arabidopsis thaliana (Robinson et al, 1999). Further FRO genes have been reported in a variety of plants such as Arachis hypogaea (Ding et al, 2009), Cucumis sativus (Waters et al, 2007), Lotus japonicus (Klein et al, 2012), Malus xiaojinensis (Wu et al, 2012), Medicago truncatula (Andaluz et al, 2009;Orozco-Mosqueda et al, 2012), Oryza sativa (Gross et al, 2003), Pisum sativum (Waters et al, 2002), and Solanum lycopersicum (Kong et al, 2013;Li et al, 2004). Eight FROs have been described in the genome of A. thaliana and shown to exhibit tissue-specific expression (Mukherjee et al, 2006;Wu et al, 2005).…”

Bacterial Compound N,N-Dimethylhexadecylamine Modulates Expression of Iron Deficiency and Defense Response Genes in Medicago truncatula Independently of the Jasmonic Acid Pathway

“…All the identified genes showed at least 60% identity with their A. thaliana orthologues and the sequences of the characteristic domains of each protein (Table S1). The key genes MtFRO3 [27,36] (iron-deficiency response), and MtDef2.1 [37] (ISR response) have been previously described.…”

Physiological and Transcriptome Analyses Revealed the Mechanism by Which Deferoxamine Promotes Iron Absorption in Cinnamomum camphora

“…Transcriptome sequencing refers to the use of second generation high−throughput sequencing technology for cDNA sequencing, which can comprehensively and quickly obtain almost all transcripts of a specific organ or tissue of a species in a certain state [ 20 , 21 , 22 ]. In recent years, RNA−seq technology has been used to analyse the molecular mechanism of plant tolerance to iron deficiency stress, and key FRO , IRT and TF family genes have been found in many plant species, such as Arabidopsis thaliana , pea, cucumber and tomato [ 23 , 24 , 25 ]. Cinnamomum camphora is a common tree species in urban landscaping.…”