ELONGATED HYPOCOTYL 5 regulates BRUTUS and affects iron acquisition and homeostasis in Arabidopsis thaliana.

Iron (Fe) is an essential micronutrient for both plants and animals. Fe-limitation significantly reduces crop yield and adversely impacts on human nutrition. Owing to limited bioavailability of Fe in soil, plants have adapted different strategies that not only regulate Fe-uptake and homeostasis but also bring modifications in root system architecture to enhance survival. Understanding the molecular mechanism underlying the root growth responses will have critical implications for plant breeding. Fe-uptake is regulated by a cascade of basic helix-loop-helix (bHLH) transcription factors (TFs) in plants. In this study, we report that HY5 (Elongated Hypocotyl 5), a member of the basic leucine zipper (bZIP) family of TFs, plays an important role in the Fe-deficiency signaling pathway in Arabidopsis thaliana. The hy5 mutant failed to mount optimum Fe-deficiency responses, and displayed root growth defects under Fe-limitation. Our analysis revealed that the induction of the genes involved in Fe-uptake pathway (FIT-FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR, FRO2-FERRIC REDUCTION OXIDASE 2 and IRT1-IRON-REGULATED TRANSPORTER1) is reduced in the hy5 mutant as compared with the wild-type plants under Fe-deficiency. Moreover, we also found that the expression of coumarin biosynthesis genes is affected in the hy5 mutant under Fe-deficiency. Our results also showed that HY5 negatively regulates BRUTUS (BTS) and POPEYE (PYE). Chromatin immunoprecipitation followed by quantitative polymerase chain reaction revealed direct binding of HY5 to the promoters of BTS, FRO2 and PYE. Altogether, our results showed that HY5 plays an important role in the regulation of Fe-deficiency responses in Arabidopsis.

A tale of two players: the role of phosphate in iron and zinc homeostatic interactions.

MAIN CONCLUSION: This minireview details the impact of iron-phosphate and zinc-phosphate interactions in plants and provides perspectives for further areas of research regarding nutrient homeostasis. Iron (Fe) and zinc (Zn) are among the most important micronutrients for plant growth and have numerous implications for human health and agriculture. While plants have developed efficient uptake and transport mechanisms for Fe and Zn, emerging research has shown that the availability of other nutrients in the environment influences the homeostasis of Fe and Zn within plants. In this minireview, we present the current knowledge regarding homeostatic interactions of Fe and Zn with the macronutrient phosphorous (P) and the resulting physiological responses to combined deficiencies of these nutrients. Fe and P interactions have been shown to influence root development, photosynthesis, and biological processes aiding Fe uptake. Zn and P interactions also influence root growth, and coordination of Zn-dependent transcriptional regulation contributes to phosphate (Pi) transport in the plant. Understanding homeostatic interactions among these different nutrients is of critical importance to obtain a more complete understanding of plant nutrition in complex soil environments.

Contrasting ß-ODAP content correlates with stress gene expression in Lathyrus cultivars.

Lathyrus sativus, commonly known as grass pea, is a nutrient-rich pulse crop with remarkable climate-resilient attributes. However, wide use of this nutritious crop is not adopted owing to the presence of a non-protein amino acid ß-N-oxalyl-l-α,ß-diaminopropionic acid (ß-ODAP), which is neurotoxic if consumed in large quantities. We conducted a de novo transcriptomic profiling of two ODAP contrasting cultivars, Pusa-24 and its somaclonal variant Ratan, to understand the genetic changes leading to and associated with ß-ODAP levels. Differential gene expression analysis showed that a variety of genes are downregulated in low ß-ODAP cultivar Ratan and include genes involved in biotic/abiotic stress tolerance, redox metabolism, hormonal metabolism, and sucrose, and starch metabolism. Several genes related to chromatin remodeling are differentially expressed in cultivar Ratan. ß-ODAP biosynthetic genes in these cultivars showed differential upregulation upon stress. ODAP content of these cultivars varied differentially upon stress and development. Physiological experiments indicate reduced relative water content and perturbed abscisic acid levels in the low ODAP cultivar. Altogether, our results suggest that the low ODAP cultivar may have a reduced stress tolerance. The dataset provides insight into the biological role of ODAP and will be helpful for hypothesis-driven experiments to understand ODAP biosynthesis and regulation.

Differentially reset transcriptomes and genome bias response orchestrate wheat response to phosphate deficiency.

Phosphorus (P) is an essential macronutrient for all organisms. Phosphate (Pi) deficiency reduces grain yield and quality in wheat. Understanding how wheat responds to Pi deficiency at the global transcriptional level remains limited. We revisited the available RNA-seq transcriptome from Pi-starved wheat roots and shoots subjected to Pi starvation. Genome-wide transcriptome resetting was observed under Pi starvation, with a total of 917 and 2338 genes being differentially expressed in roots and shoots, respectively. Chromosomal distribution analysis of the gene triplets and differentially expressed genes (DEGs) revealed that the D genome displayed genome induction bias and, specifically, the chromosome 2D might be a key contributor to Pi-limiting triggered gene expression response. Alterations in multiple metabolic pathways pertaining to secondary metabolites, transcription factors and Pi uptake-related genes were evidenced. This study provides genomic insight and the dynamic landscape of the transcriptional changes contributing to the hexaploid wheat during Pi starvation. The outcomes of this study and the follow-up experiments have the potential to assist the development of Pi-efficient wheat cultivars.

Whole genome re-sequencing of indian wheat genotypes for identification of genomic variants for grain iron and zinc content.

BACKGROUND: Whole-genome sequencing information which is of abundant significance for genetic evolution, and breeding of crops. Wheat (Triticum spp) is most widely grown and consumed crops globally. Micronutrients are very essential for healthy development of human being and their sufficient consumption in diet is essential for various metabolic functions. Biofortification of wheat grains with iron (Fe) and zinc (Zn) has proved the most reliable and effective way to combat micronutrient associated deficiency. Genetic variability for grain micronutrient could provide insight to dissect the traits. METHODS AND RESULTS: In the current study, 1300 wheat lines were screened for grain Fe and Zn content, out of which only five important Indian wheat genotypes were selected on the basis of Fe and Zn contents. These lines were multiplied during at the National Agri-Food Biotechnology Institute (NABI) and re-sequenced to identify genomic variants in candidate genes for Fe and Zn between the genotypes. Whole genome sequencing generated Ì´ 12 Gb clean data. Comparative genome analysis identified 254 genomic variants in the candidate genes associated with deleterious effect on protein function. CONCLUSIONS: The present study demonstrated the fundamental in understanding the genomic variations for Fe and Zn enrichment to generate healthier wheat grains.

Wheat inositol pyrophosphate kinase TaVIH2-3B modulates cell-wall composition and drought tolerance in Arabidopsis.

BACKGROUND: Inositol pyrophosphates (PP-InsPs) are high-energy derivatives of inositol, involved in different signalling and regulatory responses of eukaryotic cells. Distinct PP-InsPs species are characterized by the presence of phosphate at a variable number of the 6-carbon inositol ring backbone, and two distinct classes of inositol phosphate kinases responsible for their synthesis have been identified in Arabidopsis, namely ITPKinase (inositol 1,3,4 trisphosphate 5/6 kinase) and PP-IP5Kinase (diphosphoinositol pentakisphosphate kinases). Plant PP-IP5Ks are capable of synthesizing InsP8 and were previously shown to control defense against pathogens and phosphate response signals. However, other potential roles of plant PP-IP5Ks, especially towards abiotic stress, remain poorly understood. RESULTS: Here, we characterized the physiological functions of two Triticum aestivum L. (hexaploid wheat) PPIP5K homologs, TaVIH1 and TaVIH2. We demonstrate that wheat VIH proteins can utilize InsP7 as the substrate to produce InsP8, a process that requires the functional VIH-kinase domains. At the transcriptional level, both TaVIH1 and TaVIH2 are expressed in different wheat tissues, including developing grains, but show selective response to abiotic stresses during drought-mimic experiments. Ectopic overexpression of TaVIH2-3B in Arabidopsis confers tolerance to drought stress and rescues the sensitivity of Atvih2 mutants. RNAseq analysis of TaVIH2-3B-expressing transgenic lines of Arabidopsis shows genome-wide reprogramming with remarkable effects on genes involved in cell-wall biosynthesis, which is supported by the observation of enhanced accumulation of polysaccharides (arabinogalactan, cellulose, and arabinoxylan) in the transgenic plants. CONCLUSIONS: Overall, this work identifies a novel function of VIH proteins, implicating them in modulation of the expression of cell-wall homeostasis genes, and tolerance to water-deficit stress. This work suggests that plant VIH enzymes may be linked to drought tolerance and opens up the possibility of future research into using plant VIH-derived products to generate drought-resistant plants.

Physiological and molecular responses to combinatorial iron and phosphate deficiencies in hexaploid wheat seedlings.

Iron (Fe) and phosphorus (P) are the essential mineral nutrients for plant growth and development. However, the molecular interaction of the Fe and P pathways in crops remained largely obscure. In this study, we provide a comprehensive physiological and molecular analysis of hexaploid wheat response to single (Fe, P) and its combinatorial deficiencies. Our data showed that inhibition of the primary root growth occurs in response to Fe deficiency; however, growth was rescued when combinatorial deficiencies occurred. Analysis of RNAseq revealed that distinct molecular rearrangements during combined deficiencies with predominance for genes related to metabolic pathways and secondary metabolite biosynthesis primarily include genes for UDP-glycosyltransferase, cytochrome-P450s, and glutathione metabolism. Interestingly, the Fe-responsive cis-regulatory elements in the roots in Fe stress conditions were enriched compared to the combined stress. Our metabolome data also revealed the accumulation of distinct metabolites such as amino-isobutyric acid, arabinonic acid, and aconitic acid in the combined stress environment. Overall, these results are essential in developing new strategies to improve the resilience of crops in limited nutrients.

Decoding the genome of superior chapatti quality Indian wheat variety 'C 306' unravelled novel genomic variants for chapatti and nutrition quality related genes.

An Indian wheat variety, 'C 306' has good chapatti quality, which is controlled by multiple genes that have not been explored. We report the high quality de novo assembled genome of 'C 306' by combining short and long read sequencing data. The hybrid assembly covered 93% of gene space and identified about 142 K coding genes, 34% repetitive DNA and ~ 501 K SSR motifs. The phylogenetic analysis of about 83 K orthologous protein groups suggested the closest relationship with T. turgidum, T. aestivum and Ae. tauschii. Genome wide analysis annotated 69,217,536 genomic variants. Out of them, 1423 missense and 117 deleterious variants identified in processing, nutrition, and chapatti quality related genes such as alpha- and beta-gliadin, SSI, SSIII, SUT1, SBEI, CHS, YSL, DMAS, and NAS encoded proteins. These variants may affect quality genes. The genomic data will be potential genomic resources in wheat breeding programs for quality improvement.

Experts' Consensus on Use of Long-Acting Nitroglycerine in the Management of Angina and Chronic Coronary Syndrome in India.

AIM: To address the existing gaps in knowledge about long-acting nitroglycerine (LA-NTG) and provide recommendations to address these issues. METHODOLOGY: Approved LA-NTG questionnaire that included 17 questions related to the role of LA-NTG in the management of angina and chronic coronary syndrome (CCS) was shared with 150 expert cardiologists from different regions from India. Results of these survey questionnaires were further discussed in 12 regional level meetings. The opinions and suggestions from all the meetings were compiled and analyzed. Further, recommendations were made with the help of attending national cardiology experts and a consensus statement was derived. RESULTS: This is the first consensus on LA-NTG, summarizing the clinical evidence from India and suggesting recommendations based on these data. The experts recommended early use of LA-NTG as a first-line antianginal therapy in combination with beta-blocker since it improves exercise tolerance in patients with CCS. A strong consensus was observed for using LA-NTG in patients with co-morbid hypertension, diabetes, chronic kidney disease and post-percutaneous coronary intervention angina. As a part of cardiac rehabilitation, LA-NTG allows patients with angina to exercise to a greater functional capacity. CONCLUSIONS: A national consensus was observed for several aspects of LA-NTG in the management of angina and CCS. The clinical experience of the experts confirmed an extremely satisfied patient perception about the efficacy of LA-NTG.

Dissecting the nutrient partitioning mechanism in rice grain using spatially resolved gene expression profiling.

Rice, a staple food worldwide, contains varying amounts of nutrients in different grain tissues. The underlying molecular mechanism of such distinct nutrient partitioning remains poorly investigated. Here, an optimized rapid laser capture microdissection (LCM) approach was used to individually collect pericarp, aleurone, embryo and endosperm from grains 10 days after fertilization. Subsequent RNA-Seq analysis in these tissues identified 7760 differentially expressed genes. Analysis of promoter sequences of tissue-specific genes identified many known and novel cis-elements important for grain filling and seed development. Using the identified differentially expressed genes, comprehensive spatial gene expression pathways were built for accumulation of starch, proteins, lipids, and iron. The extensive transcriptomic analysis provided novel insights about nutrient partitioning mechanisms; for example, it revealed a gradient in seed storage protein accumulation across the four tissue types analysed. The analysis also revealed that the partitioning of various minerals, such as iron, is most likely regulated through transcriptional control of their transporters. We present the extensive analysis from this study as an interactive online tool that provides a much-needed resource for future functional genomics studies aimed to improve grain quality and seed development.

Spotlight on the overlapping routes and partners for anthocyanin transport in plants.

Secondary metabolites are produced by plants and are classified based on their chemical structure or the biosynthetic routes through which they are synthesized. Among them, flavonoids, including anthocyanins and pro-anthocyanidins (PAs), are abundant in leaves, flowers, fruits, and seed coats in plants. The anthocyanin biosynthetic pathway has been intensively studied, but the molecular mechanism of anthocyanin transport from the synthesis site to the storage site needs attention. Although the major transporters are well defined yet, the redundancy of these transporters for structurally similar or dis-similar anthocyanins motivates additional research. Herein, we reviewed the role of membrane transporters involved in anthocyanin transport, including ATP-binding cassette, multidrug and toxic compound extrusion (MATE), Bilitranslocase-homolog (BTL), and vesicle-mediated transport. We also highlight the ability of transporters to cater distinct anthocyanins or their chemically-modified forms with overlapping transport mechanisms and sequestration into the vacuoles. Our understanding of the anthocyanin transporters could provide anthocyanin-rich crops and fruits with a benefit on human health at a large scale.

Feasibility, efficiency & effectiveness of pooled sample testing strategy (pooled NAAT) for molecular testing of COVID-19.

BACKGROUND & OBJECTIVES: During the current COVID-19 pandemic, a large number of clinical samples were tested by real-time PCR. Pooling the clinical samples before testing can be a good cost-saving and rapid alternative for screening large populations. The aim of this study was to compare the performance characteristics, feasibility and effectiveness of pooling nasal swab and throat swab samples for screening and diagnosis of SARS-CoV-2. METHODS: The pool testing was applied on a set of samples coming from low COVID-19 positivity areas. A total of 2410 samples were tested in pools of five samples each. A total of five pools of five samples each were generated and tested for E gene. RESULTS: Of the total of 482 pools (2410 samples) 24 pools flagged positive. Later on pool de-convolution, a total of 26 samples were detected as positive for COVID-19, leading to positivity of about one per cent in the test population. For the diagnosis of individual samples, the pooling strategies resulted in cost savings of 75 per cent (5 samples per pool). INTERPRETATION & CONCLUSIONS: It was observed that testing samples for COVID-19 by reverse transcription (RT)- PCR after pooling could be a cost-effective method which would save both in manpower and cost especially for resource-poor countries and at a time when test kits were short in supply.

Multi-metal tolerance of DHHC palmitoyl transferase-like protein isolated from metal contaminated soil.

The microbiota inhabiting in metal polluted environment develops strong defense mechanisms to combat pollution and sustain life. Investigating the functional genes of the eukaryotic microbiota inhabiting in these environments by using metatranscriptomics approach was the focus of this study. Size fractionated eukaryotic cDNA libraries (library A, < 0.5 kb, library B, 0.5-1.0 kb, and library C, > 1.0 kb) were constructed from RNA isolated from the metal contaminated soil. The library C was screened for Cadmium (Cd) tolerant genes by using Cd sensitive yeast mutant ycf1Δ by functional complementation assay, which yielded various clones capable of growing in Cd amended media. One of the Cd tolerant clones, PLCg39 was selected because of its ability to grow at high concentrations of Cd. Sequence analysis of PLCg39 showed homology with DHHC palmitoyl transferases, which are responsible for addition of palmitoyl groups to proteins and usually possess metal coordination domains. The cDNA PLCg39 was able to confer tolerance to Cd-sensitive (ycf1Δ), Copper-sensitive (cup1Δ) and Zn-sensitive (zrc1Δ) yeast mutants when grown at different concentrations of Cd (40-100 µM), Cu (150-1000 µM) and Zn (10-13 mM), respectively. The DHHC mutant akr1Δ transformed with PLCg39 rescued from the metal sensitivity indicating the role of DHHC palmitoyl transferase in metal tolerance. This study demonstrated that PLCg39 acts as a potential metal tolerant gene which could be used in bioremediation, biosensing and other biotechnological fields.

CRISPR/Cas9 directed editing of lycopene epsilon-cyclase modulates metabolic flux for ß-carotene biosynthesis in banana fruit.

Banana is one of the most economically important fruit crops worldwide. Genetic improvement in banana is a challenging task due to its parthenocarpic nature and triploid genome. Genetic modification of crops via the CRISPR/Cas9 module has emerged as a promising tool to develop important traits. In the present work, a CRISPR/Cas9-based approach was used to develop the ß-carotene-enriched Cavendish banana cultivar (cv.) Grand Naine (AAA genome). The fifth exon of the lycopene epsilon-cyclase (LCYε) gene was targeted. The targeting specificity of the designed guide-RNA was also tested by its ability to create indels in the LCYε gene at the A genome of cv. Rasthali (AAB genome). Sequence analysis revealed multiple types of indels in the genomic region of Grand Naine LCYε (GN-LCYε). Metabolic profiling of the fruit pulp of selected edited lines showed enhanced accumulation of ß-carotene content up to 6-fold (~24 µg/g) compared with the unedited plants. These lines also showed either an absence or a drastic reduction in the levels of lutein and α-carotene, suggesting metabolic reprogramming, without any significant effect on the agro-morphological parameters. In addition, differential expression of carotenoid pathway genes was observed in the edited lines in comparison to unedited plants. Overall, this is the first report in banana to improve nutritional trait by using a precise genome editing approach.

ABC Transporter-Mediated Transport of Glutathione Conjugates Enhances Seed Yield and Quality in Chickpea.

The identification of functionally relevant molecular tags is vital for genomics-assisted crop improvement and enhancement of seed yield, quality, and productivity in chickpea (Cicer arietinum). The simultaneous improvement of yield/productivity as well as quality traits often requires pyramiding of multiple genes, which remains a major hurdle given various associated epistatic and pleotropic effects. Unfortunately, no single gene that can improve yield/productivity along with quality and other desirable agromorphological traits is known, hampering the genetic enhancement of chickpea. Using a combinatorial genomics-assisted breeding and functional genomics strategy, this study identified natural alleles and haplotypes of an ABCC3-type transporter gene that regulates seed weight, an important domestication trait, by transcriptional regulation and modulation of the transport of glutathione conjugates in seeds of desi and kabuli chickpea. The superior allele/haplotype of this gene introgressed in desi and kabuli near-isogenic lines enhances the seed weight, yield, productivity, and multiple desirable plant architecture and seed-quality traits without compromising agronomic performance. These salient findings can expedite crop improvement endeavors and the development of nutritionally enriched high-yielding cultivars in chickpea.

Spatio-temporal distribution of micronutrients in rice grains and its regulation.

Rice has been a staple food for more than half of the global population. Different parts of rice grains contain different amounts of macro- and micro-nutrients. Polished white rice, which is the main form of rice consumption, mainly contains starch, however, the bran and germ, which are removed during polishing, contain large amounts of micronutrients and bioactive compounds. To engineer nutritionally superior rice varieties, it is imperative to understand the spatial and temporal distribution of different nutrients in different parts of the rice grain. Keeping this in mind, in this review, we have performed a comprehensive literature review to put together all the recent findings regarding the spatio-temporal distribution of all the important micronutrients in different cell-layers/tissues of developing seeds and mature seed grains. Furthermore, we have overviewed the underlying cell-layer specific possible regulatory mechanism responsible for the loading/partitioning for each of the micronutrients into specific tissue types. Most of the nutrient filling occurs between 7 and 18 days after fertilization (DAF) through the dorsal vascular bundle and the aleurone layer. During the last few years, spatio-temporal distribution of various minerals and the role of their transporters has been studied in great detail. However, with regard to vitamins and other bioactive compounds, such studies are still very limited. Distribution of minerals in the grain is mainly regulated by the distribution of their ligands and transporters, whereas the accumulation of various vitamins is mainly metabolic enzyme activity. Collective knowledge discussed here in this niche area would help to design new studies to improve the micronutrient content located in the inner part of the seed.

A homologous overexpression system to study roles of drug transporters in Candida glabrata.

Considering the relevance of drug transporters belonging to ABC and MFS superfamilies in pathogenic Candida species, there has always been a need to have an overexpression system where these membrane proteins for functional analysis could be expressed in a homologous background. We could address this unmet need by constructing a highly drug-susceptible Candida glabrata strain deleted in seven dominant ABC transporters genes such as CgSNQ2, CgAUS1, CgCDR1, CgPDH1, CgYCF1, CgYBT1 and CgYOR1 and introduced a GOF mutation in transcription factor (TF) CgPDR1 leading to a hyper-activation of CgCDR1 locus. The expression system was validated by overexpressing four GFP tagged ABC (CgCDR1, CgPDH1, CaCDR1 and ScPDR5) and an MFS (CgFLR1) transporters genes facilitated by an engineered expression plasmid to integrate at the CgCDR1 locus. The properly expressed and localized transporters were fully functional, as was revealed by their several-fold increased drug resistance, growth kinetics, localization studies and efflux activities. The present homologous system will facilitate in determining the role of an individual transporter for its substrate specificity, drug efflux, pathogenicity and virulence traits without the interference of other major transporters.

Extraction of Common Task Features in EEG-fMRI Data Using Coupled Tensor-Tensor Decomposition.

The fusion of simultaneously recorded EEG and fMRI data is of great value to neuroscience research due to the complementary properties of the individual modalities. Traditionally, techniques such as PCA and ICA, which rely on strong non-physiological assumptions such as orthogonality and statistical independence, have been used for this purpose. Recently, tensor decomposition techniques such as parallel factor analysis have gained more popularity in neuroimaging applications as they are able to inherently contain the multidimensionality of neuroimaging data and achieve uniqueness in decomposition without making strong assumptions. Previously, the coupled matrix-tensor decomposition (CMTD) has been applied for the fusion of the EEG and fMRI. Only recently the coupled tensor-tensor decomposition (CTTD) has been proposed. Here for the first time, we propose the use of CTTD of a 4th order EEG tensor (space, time, frequency, and participant) and 3rd order fMRI tensor (space, time, participant), coupled partially in time and participant domains, for the extraction of the task related features in both modalities. We used both the sensor-level and source-level EEG for the coupling. The phase shifted paradigm signals were incorporated as the temporal initializers of the CTTD to extract the task related features. The validation of the approach is demonstrated on simultaneous EEG-fMRI recordings from six participants performing an N-Back memory task. The EEG and fMRI tensors were coupled in 9 components out of which seven components had a high correlation (more than 0.85) with the task. The result of the fusion recapitulates the well-known attention network as being positively, and the default mode network working negatively time-locked to the memory task.

Rpp1 Encodes a ULP1-NBS-LRR Protein That Controls Immunity to Phakopsora pachyrhizi in Soybean.

Phakopsora pachyrhizi is the causal agent of Asian soybean rust. Susceptible soybean plants infected by virulent isolates of P. pachyrhizi are characterized by tan-colored lesions and erumpent uredinia on the leaf surface. Germplasm screening and genetic analyses have led to the identification of seven loci, Rpp1 to Rpp7, that provide varying degrees of resistance to P. pachyrhizi (Rpp). Two genes, Rpp1 and Rpp1b, map to the same region on soybean chromosome 18. Rpp1 is unique among the Rpp genes in that it confers an immune response (IR) to avirulent P. pachyrhizi isolates. The IR is characterized by a lack of visible symptoms, whereas resistance provided by Rpp1b to Rpp7 results in red-brown foliar lesions. Rpp1 maps to a region spanning approximately 150 kb on chromosome 18 between markers Sct_187 and Sat_064 in L85-2378 (Rpp1), an isoline developed from Williams 82 and PI 200492 (Rpp1). To identify Rpp1, we constructed a bacterial artificial chromosome library from soybean accession PI 200492. Sequencing of the Rpp1 locus identified three homologous nucleotide binding site-leucine rich repeat (NBS-LRR) candidate resistance genes between Sct_187 and Sat_064. Each candidate gene is also predicted to encode an N-terminal ubiquitin-like protease 1 (ULP1) domain. Cosilencing of the Rpp1 candidates abrogated the immune response in the Rpp1 resistant soybean accession PI 200492, indicating that Rpp1 is a ULP1-NBS-LRR protein and plays a key role in the IR.

Overlapping transcriptional expression response of wheat zinc-induced facilitator-like transporters emphasize important role during Fe and Zn stress.

BACKGROUND: Hexaploid wheat is an important cereal crop that has been targeted to enhance grain micronutrient content including zinc (Zn) and iron (Fe). In this direction, modulating the expression of plant transporters involved in Fe and Zn homeostasis has proven to be one of the promising approaches. The present work was undertaken to identify wheat zinc-induced facilitator-like (ZIFL) family of transporters. The wheat ZIFL genes were characterized for their transcriptional expression response during micronutrient fluctuations and exposure to multiple heavy metals. RESULTS: The genome-wide analyses resulted in identification of fifteen putative TaZIFL-like genes, which were distributed only on Chromosome 3, 4 and 5. Wheat ZIFL proteins subjected to the phylogenetic analysis showed the uniform distribution along with rice, Arabidopsis and maize. In-silico analysis of the promoters of the wheat ZIFL genes demonstrated the presence of multiple metal binding sites including those which are involved in Fe and heavy metal homeostasis. Quantitative real-time PCR analysis of wheat ZIFL genes suggested the differential regulation of the transcripts in both roots and shoots under Zn surplus and also during Fe deficiency. Specifically, in roots, TaZIFL2.3, TaZIFL4.1, TaZIFL4.2, TaZIFL5, TaZIFL6.1 and TaZIFL6.2 were significantly up-regulated by both Zn and Fe. This suggested that ZIFL could possibly be regulated by both the nutrient stress in a tissue specific manner. When exposed to heavy metals, TaZIFL4.2 and TaZIFL7.1 show significant up-regulation, whereas TaZIFL5 and TaZIFL6.2 remained almost unaffected. CONCLUSION: This is the first report for detailed analysis of wheat ZIFL genes. ZIFL genes also encode for transporter of mugineic acid (TOM) proteins, that are involved in the release of phytosiderophores to enhance Fe/Zn uptake. The detailed expression analysis suggests the varying expression patterns during development of wheat seedlings and also against abiotic/biotic stresses. Overall, this study will lay foundation to prioritize functional assessment of the candidate ZIFL as a putative TOM protein in wheat.