Genome-Wide Identification, Characterization and Expression Profiling of Potato (Solanum tuberosum) Frataxin (FH) Gene.

Frataxin (FH) plays a crucial role in the biogenesis of mitochondria and the regulation of iron in the cells of various organisms. However, there has been very little research on FH in plants. In this study, the potato FH gene (StFH) was identified and characterized using a genome-wide approach, and its sequence was compared to those of FH genes from Arabidopsis, rice, and maize. The FH genes were found to have a lineage-specific distribution and were more conserved in monocots than in dicots. While multiple copies of FH genes have been reported in some species, including plants, only one isoform of FH was found in potato. The expression of StFH in leaves and roots was analyzed under two different abiotic stress conditions, and the results showed that StFH was upregulated more in leaves and that its expression levels increased with the severity of the stress. This is the first study to examine the expression of an FH gene under abiotic stress conditions.

Precision Oncology: An Ensembled Machine Learning Approach to Identify a Candidate mRNA Panel for Stratification of Patients with Breast Cancer.

The rise of machine learning (ML) has recently buttressed the efforts for big data-driven precision oncology. This study used ensemble ML for precision oncology in breast cancer, which is one of the most common malignancies worldwide with marked heterogeneity of the underlying molecular mechanisms. We analyzed clinical and RNA-seq data from The Cancer Genome Atlas (TCGA) (844 patients with breast cancer and 113 healthy individuals) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) (1784 patients with breast cancer and 202 healthy individuals). We evaluated six algorithms in the context of ensemble modeling and identified a candidate mRNA diagnostic panel that can differentiate patients from healthy controls, and stratify breast cancer into molecular subtypes. The ensemble model included 50 mRNAs and displayed 82.55% accuracy, 79.22% specificity, and 84.55% sensitivity in stratifying patients into molecular subtypes in TCGA cohort. Its performance was markedly higher, however, in distinguishing the basal, LumB, and Her2+ breast cancer subtypes from healthy individuals. In overall survival analysis, the mRNA panel showed a hazard ratio of 2.25 (p = 5 × 10-7) for breast cancer and was significantly associated with molecular pathways related to carcinogenesis. In conclusion, an ensemble ML approach, including 50 mRNAs, was able to stratify patients with different breast cancer subtypes and differentiate them from healthy individuals. Future prospective studies in large samples with deep phenotyping can help advance the ensemble ML approaches in breast cancer. Advanced ML methods such as ensemble learning are timely additions to the precision oncology research toolbox.

Mitochondrial iron transporter (MIT) gene in potato (Solanum tuberosum): comparative bioinformatics, physiological and expression analyses in response to drought and salinity.

Mitochondrial iron transporter (MIT) genes are essential for mitochondrial acquisition/import of iron and vital to proper functioning of mitochondria. Unlike other organisms, research on the MITs in plants is limited. The present study provides comparative bioinformatics assays for the potato MIT gene (StMIT) as well as gene expression analyses. The phylogenetic analyses revealed monocots-dicot divergence in MIT proteins and it was also found clade specific motif diversity. In addition, docking analyses indicated that Asp172 and Gly100 residues to be identified as the closest residues binding to ferrous iron. The percentage of structure overlap of the StMIT 3D protein model with Arabidopsis, maize and rice MIT proteins was found between 80.18% and 85.71%. The transcript analyses exhibited that the expression of StMIT was triggered under drought and salinity stresses. The findings of the present study would provide valuable leads for further studies targeting specifically the MIT gene and generally the plant iron metabolism.

Genome-wide identification of serine acetyltransferase (SAT) gene family in rice (Oryza sativa) and their expressions under salt stress.

BACKGROUND: Assimilation of sulfur to cysteine (Cys) occurs in presence of serine acetyltransferase (SAT). Drought and salt stresses are known to be regulated by abscisic acid, whose biosynthesis is limited by Cys. Cys is formed by cysteine synthase complex depending on SAT and OASTL enzymes. Functions of some SAT genes were identified in Arabidopsis; however, it is not known how SAT genes are regulated in rice (Oryza sativa) under salt stress. METHODS AND RESULTS: Sequence, protein domain, gene structure, nucleotide, phylogenetic, selection, gene duplication, motif, synteny, digital expression and co-expression, secondary and tertiary protein structures, and binding site analyses were conducted. The wet-lab expressions of OsSAT genes were also tested under salt stress. OsSATs have underwent purifying selection. Segmental and tandem duplications may be driving force of structural and functional divergences of OsSATs. The digital expression analyses of OsSATs showed that jasmonic acid (JA) was the only hormone inducing the expressions of OsSAT1;1, OsSAT2;1, and OsSAT2;2 whereas auxin and ABA only triggered OsSAT1;1 expression. Leaf blade is the only plant organ where all OsSATs but OsSAT1;1 were expressed. Wet-lab expressions of OsSATs indicated that OsSAT1;1, OsSAT1;2 and OsSAT1;3 genes were upregulated at different exposure times of salt stress. CONCLUSIONS: OsSAT1;1, expressed highly in rice roots, may be a hub gene regulated by cross-talk of JA, ABA and auxin hormones. The cross-talk of the mentioned hormones and the structural variations of OsSAT proteins may also explain the different responses of OsSATs to salt stress.

An Insight into Oligopeptide Transporter 3 (OPT3) Family Proteins.

BACKGROUND: OPT3s are involved in the transport of Fe from xylem to phloem, in loading Fe into phloem, and in the transmission of shoot-to-root iron signaling. Yet, apart from Arabidopsis, little is known about these transporters'functions in other plant species. OBJECTIVE: OPT3 proteins of several plant species were characterized using bioinformatical tools. Also, a probable Fe chelating protein, GSH, was used in docking analyses to shed light on the interactions of ligand binding sites of OPT3s. METHODS: The multiple sequence alignment (MSA) analysis, protein secondary and tertiary structure analyses, molecular phylogeny analysis, transcription factor binding site analyses, co-expression and docking analyses were performed using up-to-date bioinformatical tools. RESULTS: All OPT3s in this study appear to be transmembrane proteins. They appear to have broad roles and substrate specificities in different metabolic processes. OPT3 gene structures were highly conserved. Promoter analysis showed that bZIP, WRKY, Dof and AT-Hook Transcription factors (TFs) may regulate the expression of OPT3 genes. Consequently, they seemed to be taking part in both biotic and abiotic stress responses as well as growth and developmental processes. CONCLUSION: The results showed that OPT3 proteins are involved in ROS regulation, plant stress responses, and basal pathogen resistance. They have species-specific roles in biological processes. Lastly, the transport of iron through OPT3s may occur with GSH according to the binding affinity results of the docking analyses.

Gallic acid (GA) alleviating copper (Cu) toxicity in maize (Zea mays L.) seedlings.

The aim of this study is to determine the effect of GA on maize seedlings as well as its antioxidative effect under copper (Cu) stress. To that end, maize seedlings were exposed to 1.5 mM GA and 1 mM Cu solutions, and the seedlings were allocated to following experimental groups: 18-hr distilled water (DI) (Control), 6-hr GA + 12-hr DI (GA), 6-hr DI + 12-hr Cu (Cu), 6-hr GA + 12-hr Cu (GA + Cu), 12-hr Cu +6-hr GA (Cu + GA), and 18-hr GA and Cu mixture (GA = Cu). The experiment was designed by randomized block design with three repetitions. The results showed that GA alone and GA + Cu treatments significantly decreased membrane damage and H2O2 formation compared to the other treatments. GA formation was determined to be highest in turn in treatments GA + Cu and GA alone. The proline content significantly decreased in treatments GA alone and GA + Cu. The highest catalase (CAT) activity was observed in GA alone application, whereas GA + Cu treatment led to increase in guaiacol peroxidase (GPX), superoxide dismutase (SOD), and ascorbate peroxidase (APX) activities. GA has a protective effect on chlorophyll contents and relative water content (RWC), but not on carotenoid levels under Cu stress. Overall, GA alone application or GA + Cu stress may prevent the formation of reactive oxygen species (ROS) due to chelation effect of GA.

A key gene bHLH115 in iron homeostasis: comprehensive bioinformatics analyses in Arabidopsis, tomato, rice, and maize.

bHLH115 transcription factor (TF) is a positive regulator of the Fe-deficiency and plays essential roles in the stress-related regulation network. In this study, orthologous bHLH115 genes in Arabidopsis, tomato, rice, and maize were analyzed using in silico methods. All bHLH115 proteins contained PF00010 (HLH: Helix-loop-helix DNA-binding domain) domain structure and their sub-cellular localizations were predicted as nucleus. The bHLH115 orthologues in monocots and dicots clearly diverged from each other. The expression analyses revealed that orthologous genes of bHLH115 in queried species were highly expressed in seed parts, leaf, stem, and flower parts. The bHLH115 genes were co-expressed with genes in plant defense system, and with genes involving in biotic and abiotic stress responses. In terms of protein structures, OsbHLH115 and ZmbHLH115, and AtbHLH115 and SlbHLH115 had the highest protein structure similarities. In addition, bHLH115 proteins have bZIP, bHLH and MYB transcription factor binding sites strengthens their engagement in various metabolic ways. Molecular docking analyses showed the different binding sites based on plant species, suggesting functional flexibilities of bHLH115 gene.

Genome-wide and comparative analysis of bHLH38, bHLH39, bHLH100 and bHLH101 genes in Arabidopsis, tomato, rice, soybean and maize: insights into iron (Fe) homeostasis.

Iron (Fe) is an essential element for plant life. Its deficiency impedes growth and development and excessive iron can cause the toxic effect via the Fenton reaction. Thus, plants have developed various mechanisms to acquire, distribute and utilize Fe for the maintenance of their iron homeostasis at cellular and systemic levels. A basic helix-loop-helix (bHLH) transcription factor family plays essential roles in many regulatory and development processes in plants. In this study, we aimed to understand the roles of bHLH38, bHLH39, bHLH100 and bHLH101 genes for Fe homeostasis in Arabidopsis, tomato, rice, soybean and maize species by using bioinformatics approaches. The gene/protein sequence analyses of these genes demonstrated that all bHLH proteins comprised helix-loop-helix DNA binding domain (PF00010) with varied exon numbers between 2 and 13. The phylogenetic analysis did not reveal a clear distinction between monocot and dicot plants. A total of 61 cis-elements were found in promotor sequences, including biotic and abiotic stress responsiveness, hormone responsiveness, and tissue specific expressions. The some structural divergences were identified in predicted 3D structures of bHLH proteins with different channels numbers. The co-expression network analysis demonstrated that bHLH39 and bHLH101 played more important roles in Fe regulation in Arabidopsis. The digital expression analysis showed various expression profiles of bHLH genes which were identified in developmental stages, anatomical parts, and perturbations. Particularly, bHLH39 and bHLH101 genes were found to be more active genes in Fe homeostasis. As a result, our findings can contribute to understanding of bHLH38, bHLH39, bHLH100 and bHLH101 genes in Fe homeostasis in plants.

Simultaneous hyperaccumulation of multiple heavy metals by Helianthus annuus grown in a contaminated sandy-loam soil.

Phytoremediation is a promising means for the treatment of contamination arising from heavy metal spills. Although several species have been identified as hyperaccumulators, most of the studies were performed with only one heavy metal. Experiments were conducted with two cultivars of H. annuus exposed to different combinations of metal contamination (30 mg/kg Cd, Cr, Ni, As, and/or Fe). Cultivar efficiency was based on total metal uptake, as well as translocation and selectivity of each metal. The results for each cultivar were also compared after 0.1 g/kg or 0.3 g/kg EDTA was added to enhance metal bioavailability. The key finding was that H. annuus achieved hyperaccumulator status for multiple metals simultaneously: Cd, Cr, and As.