Genome Wide Identification of Orthologous ZIP Genes Associated with Zinc and Iron Translocation in Setaria italica

Abstract

Genes in the ZIP family encode transcripts to store and transport bivalent metal micronutrient, particularly iron (Fe) and or zinc (Zn). These transcripts are important for a variety of functions involved in the developmental and physiological processes in many plant species, including most, if not all, Poaceae plant species and the model species Arabidopsis. Here, we present the report of a genome wide investigation of orthologous ZIP genes in Setaria italica and the identification of 7 single copy genes. RT-PCR shows 4 of them could be used to increase the bio-availability of zinc and iron content in grains. Of 36 ZIP members, 25 genes have traces of signal peptide based sub-cellular localization, as compared to those of plant species studied previously, yet translocation of ions remains unclear. In silico analysis of gene structure and protein nature suggests that these two were preeminent in shaping the functional diversity of the ZIP gene family in S. italica. NAC, bZIP and bHLH are the predominant Fe and Zn responsive transcription factors present in SiZIP genes. Together, our results provide new insights into the signal peptide based/independent iron and zinc translocation in the plant system and allowed identification of ZIP genes that may be involved in the zinc and iron absorption from the soil, and thus transporting it to the cereal grain underlying high micronutrient accumulation.

Discovery and validation of candidate genes for grain iron and zinc metabolism in pearl millet [Pennisetum glaucum (L.) R. Br.]

“…Therefore, biofortification of cereals or increasing their bioavailability in the edible parts like endosperm can cost-effectively solve the problem of malnutrition and save millions of lives across the globe 35 . Among the Fe and Zn superfamily, genes such as YSL, ZIP, NRAMP, FER, NAS have been identified in many plants like Arabidopsis thaliana 36 , Setaria italica 29 and Oryza sativa 28 . These genes were responsible for Fe and Zn translocation from soil to the grain filling sight.…”

“…In Oryza sativa, 17 ZIP genes 47 , 15 in Arabidopsis thaliana 10 , 12 in Poncirus trifoliata 48 , and 9 in Zea mays 46 were reported. Alagarasan et al 29 on the other hand, identified 36 ZIP family members in Setaria italica. In contrast, in the present study, 8 ZIP family members (out of a total of 29 iron and zinc transporter genes) were noticed in the genome of P. glaucum.…”

“…The present study involves the identification of genes associated with Fe and Zn metabolism, gene structures, characterization, chromosomal localizations, grain Fe and Zn quantification and tissue-specific expression of these genes in P. glaucum. Unraveling the intricate mechanisms associated with Fe and Zn metabolism and the gene expression analysis should also help us in understanding better grain micronutrient nutrition in cereal crops 29 .…”

Structure, Function, Regulation and Phylogenetic Relationship of ZIP Family Transporters of Plants

“…But, the information about ZIP genes is limited. Alagarasan et al (2017) identified seven SiZIP genes (SiZIP1-SiZIP7) in foxtail millet. The expression pattern of seven SiZIP genes was analyzed in root, leaf, stem and spica tissues of foxtail millet grown under drought stress without any additional nutrient supplementation.…”

Two Cassava Basic Leucine Zipper (bZIP) Transcription Factors (MebZIP3 and MebZIP5) Confer Disease Resistance against Cassava Bacterial Blight

“…With the conserved bZIP domain, bZIP family is one of the largest transcription factors in plants. The bZIP domain contains two structural features, a basic region and a leucine zipper ( Alagarasan et al, 2017 ; Zha et al, 2017 ). The basic region consists of about 16 amino acid residues and an invariant N-x7-R/K motif, which are responsible for nuclear localization and DNA binding, respectively.…”