Identification of putative target genes to manipulate Fe and Zn concentrations in rice grains (original) (raw)
Related papers
Journal of Plant Molecular Biology and …, 2011
Expression of twenty five metal transport related genes was analyzed in root and leaf tissue of twelve diverse rice genotypes at maximum tillering (MTS) and mid-grain fill (MGF) stages to understand their role in iron/zinc uptake and transport and remobilization. Well-nourished rice plants grown with sufficient supply of iron (Fe) and zinc (Zn) were used for expression analysis. Differential expression of metal homeostasis related candidate genes was observed among genotypes, tissue types and developmental stages. Maximum number of genes (twenty four) genes expressed in flag leaf tissue (MGF) showing variation in level of expression among genotypes. Root transcriptome profiling revealed that nine genes (OsZIP4,
Plant Science, 2018
Biofortification of rice (Oryza sativa L.) would alleviate iron and zinc deficiencies in the target populations. We identified two alleles 261 and 284 of a Gramineae-specific heavy metal transporter gene OsHMA7 by analyzing expression patterns and sequences of genes within QTLs for high Fe & Zn, in Madhukar x Swarna recombinant inbred lines (RILs) with high (HL) or low (LL) grain Fe & Zn. Overexpression of 261 allele increased grain Fe and Zn but most of the transgenic plants either did not survive or did not yield enough seeds and could not be further characterized. Knocking down expression of OsHMA7 by RNAi silencing of endogenous gene resulted in plants with altered domestication traits such as plant height, tiller number, panicle size and architecture, grain color, shape, size, grain shattering, heading date and increased sensitivity to Fe and Zn deficiency. However, overexpression of 284 allele resulted in transgenic lines with either high grain Fe & Zn content (HL-ox) and tolerance to Fe and Zn deficiency or low grain Fe & Zn content (LL-ox) and phenotype similar to RNAi-lines. OsHMA7 transcript levels were five-fold higher in the HL-ox plants whereas LL-ox and RNAi plants showed 2-3 fold reduced levels compared to Kitaake control. Spraying LL-ox and RNAi lines with Fe & Zn at grain filling stage resulted in increased grain yield, significant increase in Fe & Zn content and brown pericarp. Altered expression of OsHMA7 influenced transcript levels of iron-responsive genes indicating cellular Fe-Zn homeostasis and also several domestication-related genes in rice. Our study shows that a novel heavy metal transporter gene influences yield and grain Fe & Zn content and has potential to improve rice production and biofortification.
Current Science, 2015
To understand the role of metal homeostasis-related genes in rice, micronutrient levels of different tissue types were analysed at mid grain-filling stage followed by the expression analysis of candidate genes in these tissues. Subsequently, the association between the gene expression pattern and micronutrient level in tissues as well as mature grains was analysed. Out of 11 candidate genes used for gene expression analysis utilizing bulked cDNA based RT-PCR, 8 genes showed high level of expression in flag leaf and second leaf tissues. Four genes showed poor level of expression in immature grains and low to negligible expression in stem tissues. Further, six candidate genes were selected based on differential response of cDNA bulk analysis for the expression studies of individual rice genotypes, including four high-zinc rice genotypes, namely R-RHZ-LI-25, IR92970-111-1-2, R-RHZ-SM-3, R-RHZ-SM-4 which showed higher level of expression for genes OsVIT1, OsFER1, OsYSL2 and OsYSL9. Whereas low or negligible level gene expression in stem tissue of five genes, except OsFER1 shows that rice stem tissue could be involved in the uptake of micronutrients. The characterization of genes in this study provides deeper insight into the tightly regulated mechanism of metal homeostasis with respect to different tissue types and understanding of sourcesink relationship of mineral acquisition and remobilization.
Characterization of Metal Homeostasis Related Rice Gene Orthologs Innutri- Rich Minor Millets
The International Journal of Plant, Animal and Environmental Sciences, 2015
Minor millets are nutritious food crops which bear potentials to serve as future food to combat the deep rooted malnutrition and nutritional insecurity prevailing in the developing world. The presented study focuses on characterizing different minor millet genotypes for grain micronutrient content along with the expression analysis of related genes. The study revealed higher level of iron and zinc content in millet grains as compared to major cereal crops. Fe content ranged from 25.65 μg/g in Kodo millet to 42.13 μg/g in Barnyard millet. In regard to grain zinc content, it ranged from 20.66 μg/g in Kodo millet to 54.34 μg/g in Barnyard millet. Expression analysis of sixteen metal homeostasis related rice gene orthologs depicted variable gene expression levels in seven genotypes of minor millets in flag leaf tissues at mid grain filling stage. VIT1 gene showed expression in all minor millets genotype with high level of expression in Sawa local, Melaghat-1, Melaghat-2, RLM-37, and TNA...
Plant and Soil, 2009
To investigate the flow of the metal nutrients iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) during rice seed germination, we performed microarray analysis to examine the expression of genes involved in metal transport. Many kinds of metal transporter genes were strongly expressed and their expression levels changed during rice seed germination. We found that metal transporter genes such as ZIP family has tendency to decrease in their expressions during seed germination. Furthermore, imaging of the distribution of elements (Fe, Mn, Zn, and Cu) was carried out using Synchrotronbased X-ray microfluorescence at the Super Photon ring-8 GeV (SPring-8) facility. The change in the distribution of each element in the seeds following germination was observed by in vivo monitoring. Iron, Mn, Zn, and Cu accumulated in the endosperm and embryos of rice seeds, and their distribution changed during rice seed germination. The change in the patterns of mineral localization during germination was different among the elements observed.
PloS one, 2018
Polished rice is poor source of micronutrients, however wide genotypic variability exists for zinc uptake and remobilization and zinc content in brown and polished grains in rice. Two landraces (Chittimutyalu and Kala Jeera Joha) and one popular improved variety (BPT 5204) were grown under zinc sufficient soil and their analyses showed high zinc in straw of improved variety, but high zinc in polished rice in landraces suggesting better translocation ability of zinc into the grain in landraces. Transcriptome analyses of the panicle tissue showed 41182 novel transcripts across three samples. Out of 1011 differentially expressed exclusive transcripts by two landraces, 311 were up regulated and 534 were down regulated. Phosphate transporter-exporter (PHO), proton-coupled peptide transporters (POT) and vacuolar iron transporter (VIT) showed enhanced and significant differential expression in landraces. Out of 24 genes subjected to quantitative real time analyses for confirmation, eight g...
Identifying QTLs/genes for iron and zinc in rice grains can help in biofortification programs. 168 F 7 RILs derived from Madhukar × Swarna were used to map QTLs for iron and zinc concentrations in unpolished rice grains. Iron ranged from 0.2 to 224 ppm and zinc ranged from 0.4 to 104 ppm. Genome wide mapping using 101 SSRs and 9 gene specific markers showed 5 QTLs on chromosomes 1, 3, 5, 7 and 12 significantly linked to iron, zinc or both. In all, 14 QTLs were identified for these two traits. QTLs for iron were co-located with QTLs for zinc on chromosomes 7 and 12. In all, ten candidate genes known for iron and zinc homeostasis underlie 12 of the 14 QTLs. Another 6 candidate genes were close to QTLs on chromosomes 3, 5 and 7. Thus the high priority candidate genes for high Fe and Zn in seeds are OsYSL1 and OsMTP1 for iron, OsARD2, OsIRT1, OsNAS1, OsNAS2 for zinc and OsNAS3, OsNRAMP1, Heavy metal ion transport and APRT for both iron and zinc together based on our genetic mapping studies as these genes strictly underlie QTLs. Several elite lines with high Fe, high Zn and both were identified.
Differential Metal Selectivity and Gene Expression of Two Zinc Transporters from Rice
PLANT PHYSIOLOGY, 2003
Zinc is an essential mineral for a wide variety of physiological and biochemical processes. To understand zinc transport in cereals, we identified putative zinc transporters in gene databases. Three full-length cDNAs were identified and characterized from rice (Oryza sativa). Two of the cDNAs partially complemented a yeast (Saccharomyces cerevisiae) mutant deficient in zinc uptake at low concentrations. The two transporters showed many similarities in function but differed in ionic selectivity and pH optimum of activity. Expression patterns also differed between the two genes. One gene was broadly expressed under all conditions, and the other gene was mainly induced by zinc deficiency to higher levels in roots than in leaves. Although the timing of expression differed between the two genes, localization of expression overlapped in roots. Comparisons of the protein sequences, ionic selectivity, and gene expression patterns of the two transporters suggest that they may play different ...
The knockdown of OsVIT2 and MIT affects iron localization in rice seed
Rice (New York, N.Y.), 2013
The mechanism of iron (Fe) uptake in plants has been extensively characterized, but little is known about how Fe transport to different subcellular compartments affects Fe localization in rice seed. Here, we discuss the characterization of a rice vacuolar Fe transporter 2 (OsVIT2) T-DNA insertion line (osvit2) and report that the knockdown of OsVIT2 and mitochondrial Fe transporter (MIT) expression affects seed Fe localization. osvit2 plants accumulated less Fe in their shoots when grown under normal or excess Fe conditions, while the accumulation of Fe was comparable to that in wild-type (WT) plants under Fe-deficient conditions. The accumulation of zinc, copper, and manganese also changed significantly in the shoots of osvit2 plants. The growth of osvit2 plants was also slow compared to that of WT plants. The concentration of Fe increased in osvit2 polished seeds. Previously, we reported that the expression of OsVIT2 was higher in MIT knockdown (mit-2) plants, and in this study, t...
Cloning an iron-regulated metal transporter from rice
Journal of Experimental Botany, 2002
Rice cDNA and genomic libraries were screened in order to clone an Fe(II) transporter gene. A cDNA clone highly homologous to the Arabidopsis Fe(II) transporter gene IRT1 was isolated from Fe-de®cient rice roots. The cDNA clone was named OsIRT1. A genomic clone corresponding to the cDNA was also obtained, sequenced and analysed. When expressed in yeast cells, OsIRT1 cDNA reversed the growth defects of the yeast iron-uptake mutant. Northern blot analysis revealed that OsIRT1 mRNA was predominantly expressed in roots and was induced by Fe-and Cu-de®ciency. This suggests that OsIRT1 is a functional metal transporter for iron, and is actively engaged in Fe uptake from soils, especially under limiting conditions.