Next Generation Sequencing, and Development of a Pipeline as a Tool for the Detection and Discovery of Citrus Pathogens to Facilitate Safer Germplasm Exchange.

Citrus is affected by many diseases, and hence, the movement of citrus propagative materials is highly regulated in the USA. Currently used regulatory pathogen detection methods include biological and laboratory-based technologies, which are time-consuming, expensive, and have many limitations. There is an urgent need to develop alternate, rapid, economical, and reliable testing methods for safe germplasm exchange. Citrus huanglongbing (HLB) has devastated citrus industries leading to an increased need for germplasm exchanges between citrus growing regions for evaluating many potentially valuable hybrids for both HLB resistance and multilocational performance. In the present study, Next-Generation Sequencing (NGS) methods were used to sequence the transcriptomes of 21 test samples, including 15 well-characterized pathogen-positive plants. A workflow was designed in the CLC Genomics Workbench software, v 21.0.5 for bioinformatics analysis of the sequence data for the detection of pathogens. NGS was rapid and found to be a valuable technique for the detection of viral and bacterial pathogens, and for the discovery of new citrus viruses, complementary to the existing array of biological and laboratory assays. Using NGS methods, we detected beet western yellows virus, a newly reported citrus virus, and a variant of the citrus yellow vein-associated virus associated with the "fatal yellows" disease.

Silver nanoparticles induces apoptosis of cancer stem cells in head and neck cancer.

Background: Several nano formulations of silver nanoparticles with bioconjugates, herbal extracts and anti-cancerous drug coating have been vividly studied to target cancer. Despite of such extensive studies, AgNPs (silver nanoparticles) have not reached the stage of clinical use. Out of all possible reasons for this failure, the unexplored effect on Cancer Stem Cell (CSC) population and mechanism of action of AgNPs, are the most plausible ones and are worked upon in this study. Methods: AgNPs were synthesized by chemical reduction method using sodium citrate and characterized by UV, FTIR, XRD and electron microscopy. CSC population was isolated from Cal33 cell line by MACS technique. MTT assay, trypan blue exclusion assay, Annexin V and PI based apoptosis assay and cell cycle assay were performed. Results: The results showed that synthesized AgNPs have cytotoxic activity on all cancer cell lines tested with the IC50 value of a wide range (1.5-49.21 µg/ml for cell lines and 0.0643-0.1211 µg/ml for splenocytes and thymocytes). CSCs Cal33 showed higher resistance to AgNP treatment and arrest in G1/G0 phase upon cell cycle analysis. Conclusion: AgNPs as an anti-cancer agent although have great potential but is limited by its off-target effects on normal cells and less effective on cancer stem cells at lower concentrations.

Macrophage infiltration in 3D cancer spheroids to recapitulate the TME and unveil interactions within cancer cells and macrophages to modulate chemotherapeutic drug efficacy.

BACKGROUND: Recapitulating the tumor microenvironment (TME) in vitro remains a major hurdle in cancer research. In recent years, there have been significant strides in this area, particularly with the emergence of 3D spheroids as a model system for drug screening and therapeutics development for solid tumors. However, incorporating macrophages into these spheroid cultures poses specific challenges due to the intricate interactions between macrophages and cancer cells. METHODS: To address this issue, in this study, we established a reproducible healthy multicellular 3D spheroid culture with macrophage infiltrates in order to mimic the TME and modulate the drug's efficacy on cancer cells in the presence of macrophages. A 3D spheroid was established using the human cancer cell line CAL33 and THP1 cell derived M0 macrophages were used as a source of macrophages. Cellular parameters including tumour metabolism, health, and mitochondrial mass were analysed in order to establish ideal conditions. To modulate the interaction of cancer cells with macrophage the ROS, NO, and H2O2 levels, in addition to M1 and M2 macrophage phenotypic markers, were analyzed. To understand the crosstalk between cancer cells and macrophages for ECM degradation, HSP70, HIF1α and cysteine proteases were examined in spheroids using western blotting and qPCR. RESULTS: The spheroids with macrophage infiltrates exhibited key features of solid tumors, including cellular heterogeneity, metabolic changes, nutrient gradients, ROS emission, and the interplay between HIF1α and HSP70 for upregulation of ECM degradading enzymes. Our results demonstrate that tumor cells exhibit a metabolic shift in the presence of macrophages. Additionally, we have observed a shift in the polarity of M0 macrophages towards tumor-associated macrophages (TAMs) in response to cancer cells in spheroids. Results also demonstrate the involvement of macrophages in regulating HIF-1α, HSP70, and ECM degradation cysteine proteases enzymes. CONCLUSIONS: This study has significant implications for cancer therapy as it sheds light on the intricate interaction between tumor cells and their surrounding macrophages. Additionally, our 3D spheroid model can aid in drug screening and enhance the predictive accuracy of preclinical studies. The strength of our study lies in the comprehensive characterization of the multicellular 3D spheroid model, which closely mimics the TME.

Milder Autumns May Increase Risk for Infection of Crops with Turnip Yellows Virus.

Climate change has increased the risk for infection of crops with insect-transmitted viruses. Mild autumns provide prolonged active periods to insects, which may spread viruses to winter crops. In autumn 2018, green peach aphids (Myzus persicae) were found in suction traps in southern Sweden that presented infection risk for winter oilseed rape (OSR; Brassica napus) with turnip yellows virus (TuYV). A survey was carried out in spring 2019 with random leaf samples from 46 OSR fields in southern and central Sweden using DAS-ELISA, and TuYV was detected in all fields except one. In the counties of Skåne, Kalmar, and Östergötland, the average incidence of TuYV-infected plants was 75%, and the incidence reached 100% for nine fields. Sequence analyses of the coat protein gene revealed a close relationship between TuYV isolates from Sweden and other parts of the world. High-throughput sequencing for one of the OSR samples confirmed the presence of TuYV and revealed coinfection with TuYV-associated RNA. Molecular analyses of seven sugar beet (Beta vulgaris) plants with yellowing, collected in 2019, revealed that two of them were infected by TuYV, together with two other poleroviruses: beet mild yellowing virus and beet chlorosis virus. The presence of TuYV in sugar beet suggests a spillover from other hosts. Poleroviruses are prone to recombination, and mixed infection with three poleroviruses in the same plant poses a risk for the emergence of new polerovirus genotypes. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Immunomodulatory effects of ß-defensin 2 on macrophages induced immuno-upregulation and their antitumor function in breast cancer.

BACKGROUND: Macrophages are mononuclear CD34+ antigen-presenting cells of defense mechanism and play dual roles in tumor burden. The immunomodulatory and their antitumor function of ß-defensin 2 is still unclear, despite the accumulating evidence of the response in infection. So, the aim of present study is to elucidate the role of ß-defensin 2 on the level of ROS, cytokines, chemokine expression in macrophages and antitumor function in breast cancer. METHOD: Swiss albino mice were used to harvest PEC macrophages and C127i breast cancer cells line for tumor model was used in this study. Macrophages were harvested and characterized by flow-cytometry using F4/80 and CD11c antibodies. MTT was performed to estimate cytotoxicity and dose optimization of ß-defensin 2. Oxidative stress was analyzed by H2O2 and NO estimation followed by iNOS quantified by q-PCR. Cytokines and chemokines estimation was done using q-PCR. Co-culture experiment was performed to study anti-tumor function using PI for cell cycle, Annexin -V and CFSE analysis for cell proliferation. RESULTS: PEC harvested macrophages were characterized by flow-cytometry using F4/80 and CD11c antibodies with the purity of 8% pure population of macrophages. It was found that 99% of cells viable at the maximum dose of 100 ng/ml of ß-defensin 2 in MTT. Levels of NO and H2O2 were found to be decreased in ß-defensin 2 as compared to control. Expression of cytokines of IFN-γ, IL-1α, TNF-α, TGF-ßwas found to be increased while IL-3 was decreased in ß-defensin 2 group as compared to control. Levels of chemokines CXCL-1, CXCL-5 and CCL5 increased in treated macrophages while CCL24 and CXCL-15 expression decreased. Adhesion receptor (CD32) and fusion receptor (CD204) were decreased in the ß-defensin 2 group as compared to control. Anti-tumor experiment was performed using co-culture experiment apoptosis (Annexin-V) was induced, cell cycle arrest in phage and cell proliferation of C127i cells was decreased. CONCLUSION: This is the first report of ß-defensin 2 modulates macrophage immunomodulatory and their antitumor function in breast cancer. ß-defensin 2 as a new therapeutic target for immunotherapy as an adjuvant in vaccines.

Long-Term Efficacy and Safety of RNAi-Mediated Virus Resistance in 'HoneySweet' Plum.

Interfering RNA technology has been established as an effective strategy to protect plants against viral infection. Despite this success, interfering RNA (RNAi) has rarely been applied due to the regulatory barriers that confront genetically engineered plants and concerns over possible environmental and health risks posed by non-endogenous small RNAs. 'HoneySweet' was developed as a virus-resistant plum variety that is protected by an RNAi-mediated process against Sharka disease caused by the plum pox virus. 'HoneySweet' has been approved for cultivation in the United States but not in countries where the plum pox virus is endemic. In this study, we evaluated the long-term efficacy of virus resistance in 'HoneySweet,' the nature and stability of its sRNA profile, and the potential health risks of consuming 'HoneySweet' plums. Graft-challenged 'HoneySweet' trees carrying large non-transgenic infected limbs remained virus-free after more than 10 years in the field, and the viral sequences from the non-transgenic infected limbs showed no evidence of adaptation to the RNAi-based resistance. Small RNA profiling revealed that transgene-derived sRNA levels were stable across different environments and, on average, were more than 10 times lower than those present in symptom-less fruits from virus-infected trees. Comprehensive 90-day mouse feeding studies showed no adverse health impacts in mice, and there was no evidence for potential siRNA off-target pathologies predicted by comparisons of the most abundant transgene-derived sRNAs to the mouse genome. Collectively, the data confirmed that RNAi provides a highly effective, stable, and safe strategy to combat virus diseases in crop plants.

Analysis of Small RNAs of Barley Genotypes Associated with Resistance to Barley Yellow Dwarf Virus.

Barley yellow dwarf virus (BYDV) causes an often-devastating disease of cereals that is most effectively controlled by using plant genotypes that are resistant or tolerant to the virus. New barley lines Vir8:3 and Vir13:8, with pyramided resistance genes against different pathogens and resistance gene Ryd2 against BYDV, are currently being tested. Because microRNAs (miRNAs) are associated with antiviral plant defense, here we compared the miRNA profiles in these lines and in cultivar Wysor (carrying one resistance gene, Ryd2), with and without BYDV infection and after feeding by virus-free aphids, to determine whether the miRNA profile in the resistant variety bear similarities with the newly developed lines. The BYDV titer for each group was also determined and compared to the titer in sensitive cultivar Graciosa. Among 746 miRNAs identified in barley, 66 were known miRNAs, and 680 were novel. The expression of 73 miRNAs differed significantly after BYDV infection, including the strong, specific upregulation of novel miRNA10778 that was conserved across all the barley genotypes. This miRNA belongs to the H box and ACA box (H/ACA) snoR14 family of RNAs (Rf01280) and is associated with pseudourydilation. The expression of 48 miRNAs also differed depending on the barley genotype. The profile of miRNAs expressed in Vir8:3 and Vir13:8 in response to BYDV was similar and differed from that of Wysor. Insights into the expression patterns of miRNAs in response to BYDV in barley provided here will benefit further studies toward understanding the resistance mechanisms and developing novel strategies against virus infections.

RNAi-Mediated Resistance Against Viruses in Perennial Fruit Plants.

Small RNAs (sRNAs) are 20-30-nucleotide-long, regulatory, noncoding RNAs that induce silencing of target genes at the transcriptional and posttranscriptional levels. They are key components for cellular functions during plant development, hormone signaling, and stress responses. Generated from the cleavage of double-stranded RNAs (dsRNAs) or RNAs with hairpin structures by Dicer-like proteins (DCLs), they are loaded onto Argonaute (AGO) protein complexes to induce gene silencing of their complementary targets by promoting messenger RNA (mRNA) cleavage or degradation, translation inhibition, DNA methylation, and/or histone modifications. This mechanism of regulating RNA activity, collectively referred to as RNA interference (RNAi), which is an evolutionarily conserved process in eukaryotes. Plant RNAi pathways play a fundamental role in plant immunity against viruses and have been exploited via genetic engineering to control disease. Plant viruses of RNA origin that contain double-stranded RNA are targeted by the RNA-silencing machinery to produce virus-derived small RNAs (vsRNAs). Some vsRNAs serve as an effector to repress host immunity by capturing host RNAi pathways. High-throughput sequencing (HTS) strategies have been used to identify endogenous sRNA profiles, the "sRNAome", and analyze expression in various perennial plants. Therefore, the review examines the current knowledge of sRNAs in perennial plants and fruits, describes the development and implementation of RNA interference (RNAi) in providing resistance against economically important viruses, and explores sRNA targets that are important in regulating a variety of biological processes.

Heterobimetallic (FeII/PtII)-Based Supramolecular Coordination Complexes Using 1,1'-Ferrocene Dicarboxylate: Self-Assembly and Interaction with Carbon Dots.

The synthesis and characterization of a new pyrazine-based ditopic organoplatinum(II) complex having a bite angle of 180° is reported. The facile and efficient syntheses are described of three discrete neutral Fe(II)/Pt(II) heterobimetallic SCCs with Pt(II) acceptor clips of different binding angles, 0, 120, and 180°. These new SCCs were characterized by multinuclear NMR and mass spectrometry. Electrochemical response of these ferrocene containing self-assembled ensembles was studied using cyclic voltammetry. The diplatinum acceptor organometallic clips significantly quench the fluorescence of highly emitting carbon quantum dots (CD), while the self-assembled macrocycles tend to nullify the quenching effect of the organometallic clips. Interestingly, the inefficient quenching of CD fluorescence by these SCCs was found to be directly related to the angular disposition of the binding sites in the Pt(II) based organometallic clips.

Self-Assembly of a [1 + 1] Ionic Hexagonal Macrocycle and Its Antiproliferative Activity.

A unique irregular hexagon was self-assembled using an organic donor clip (bearing terminal pyridyl units) and a complementary organometallic acceptor clip. The resulting metallamacrocycle was characterized by multinuclear NMR, mass spectrometry, and elemental analyses. Molecular modeling confirmed hexagonal shaped cavity for this metallamacrocycle which is a unique example of a discrete hexagonal framework self-assembled from only two building blocks. Cytotoxicity of the Pt-based acceptor tecton and the self-assembled PtII-based macrocycle was evaluated using three cancer cell lines and results were compared with cisplatin. Results confirmed a positive effect of the metallamacrocycle formation on cell growth inhibition.

Wheat streak mosaic virus: a century old virus with rising importance worldwide.

Wheat streak mosaic virus (WSMV) causes wheat streak mosaic, a disease of cereals and grasses that threatens wheat production worldwide. It is a monopartite, positive-sense, single-stranded RNA virus and the type member of the genus Tritimovirus in the family Potyviridae. The only known vector is the wheat curl mite (WCM, Aceria tosichella), recently identified as a species complex of biotypes differing in virus transmission. Low rates of seed transmission have been reported. Infected plants are stunted and have a yellow mosaic of parallel discontinuous streaks on the leaves. In the autumn, WCMs move from WSMV-infected volunteer wheat and other grass hosts to newly emerged wheat and transmit the virus which survives the winter within the plant, and the mites survive as eggs, larvae, nymphs or adults in the crown and leaf sheaths. In the spring/summer, the mites move from the maturing wheat crop to volunteer wheat and other grass hosts and transmit WSMV, and onto newly emerged wheat in the fall to which they transmit the virus, completing the disease cycle. WSMV detection is by enzyme-linked immunosorbent assay (ELISA), reverse transcription-polymerase chain reaction (RT-PCR) or quantitative RT-PCR (RT-qPCR). Three types of WSMV are recognized: A (Mexico), B (Europe, Russia, Asia) and D (USA, Argentina, Brazil, Australia, Turkey, Canada). Resistance genes Wsm1, Wsm2 and Wsm3 have been identified. The most effective, Wsm2, has been introduced into several wheat cultivars. Mitigation of losses caused by WSMV will require enhanced knowledge of the biology of WCM biotypes and WSMV, new or improved virus detection techniques, the development of resistance through traditional and molecular breeding, and the adaptation of cultural management tactics to account for climate change.

Cyclophilins: Less Studied Proteins with Critical Roles in Pathogenesis.

Cyclophilins (EC 5.2.1.8) belong to a subgroup of proteins known as immunophilins, which also include FK506-binding proteins and parvulins. Members of the immunophilins have two main characteristic properties: (i) peptidyl-prolyl cis-trans isomerase activity and (ii) the ability to bind immunosuppressant molecules of fungal origin. Cyclophilins are some of the most conserved proteins present in eukaryotes and prokaryotes, and they have been implicated in diverse cellular processes and responses to multiple biotic and abiotic stresses. Cyclophilins have been exploited in humans and plants extensively, but they have only recently received attention in regard to phytopathogens. In Phellinus sulphurascens and species of the genus Leptosphaeria and Phytophthora, high expression of cyclophilins was found to be related to infection. Moreover, recent studies of cyclophilins in certain phytopathogens, such as Magnaporthe oryzae, Botrytis cinerea, Cryphonectria parasitica, and Puccinia triticina, demonstrated their roles as a pathogenicity factors. In addition to pathogenicity, cyclophilins have high affinity for the immunosuppressive drug cyclosporin A, which is a potent antifungal agent. Although cyclophilins are highly conserved in phytopathogens, because they have been less studied, their role remains largely unknown. In this review, we provide detailed information on the cyclophilins in several phytopathogens, including fungi and oomycetes, as well as their role in suppressing plant immunity.

Coordination-Driven Self-Assembly of Ionic Irregular Hexagonal Metallamacrocycles via an Organometallic Clip and Their Cytotoxicity Potency.

Two new irregular hexagons (6 and 7) were synthesized from a pyrazine motif containing an organometallic acceptor clip [bearing platinum(II) centers] and different neutral donor ligands (4,4'-bipyridine or pyrazine) using a coordination-driven self-assembly protocol. The two-dimensional supramolecules were characterized by multinuclear NMR, mass spectrometry, and elemental analyses. Additionally, one of the macrocycles (6) was characterized by single-crystal X-ray analyses. Macrocycles are unique examples of [2 + 2] self-assembled ensembles that are hexagonal but irregular in shape. These hexagon frameworks require the assembly of only four tectons/subunits. The cytotoxicity of platinum(II)-based macrocycles was studied using various cell lines such as A549 (human lung carcinoma), KB (human oral cancer), MCF7 (human breast cancer), and HaCaT (human skin keratinocyte) cell lines, and the results were compared with those of cisplatin. The smaller macrocycle (7) exhibited a higher cytotoxic effect against all cell types, and its sensitivity was found to be comparable with that of cisplatin for A549 and MCF7 cells. Cell cycle analysis and live propidium iodide staining suggest that the macrocycles 6 and 7 induced a loss of membrane integrity that ultimately might lead to necrotic cell death.

The immunophilin repertoire of Plasmodiophora brassicae and functional analysis of PbCYP3 cyclophilin.

Plasmodiophora brassicae is a soil-borne pathogen that belongs to Rhizaria, an almost unexplored eukaryotic organism group. This pathogen requires a living host for growth and multiplication, which makes molecular analysis further complicated. To broaden our understanding of a plasmodiophorid such as P. brassicae, we here chose to study immunophilins, a group of proteins known to have various cellular functions, including involvement in plant defense and pathogen virulence. Searches in the P. brassicae genome resulted in 20 putative immunophilins comprising of 11 cyclophilins (CYPs), 7 FK506-binding proteins (FKBPs) and 2 parvulin-like proteins. RNAseq data showed that immunophilins were differentially regulated in enriched life stages such as germinating spores, maturing spores, and plasmodia, and infected Brassica hosts (B. rapa, B. napus and B. oleracea). PbCYP3 was highly induced in all studied life stages and during infection of all three Brassica hosts, and hence was selected for further analysis. PbCYP3 was heterologously expressed in Magnaporthe oryzae gene-inactivated ΔCyp1 strain. The new strain ΔCyp1+ overexpressing PbCYP3 showed increased virulence on rice compared to the ΔCyp1 strain. These results suggest that the predicted immunophilins and particularly PbCYP3 are activated during plant infection. M. oryzae is a well-studied fungal pathogen and could be a valuable tool for future functional studies of P. brassicae genes, particularly elucidating their role during various infection phases.

Histone chaperones in Arabidopsis and rice: genome-wide identification, phylogeny, architecture and transcriptional regulation.

BACKGROUND: Histone chaperones modulate chromatin architecture and hence play a pivotal role in epigenetic regulation of gene expression. In contrast to their animal and yeast counterparts, not much is known about plant histone chaperones. To gain insights into their functions in plants, we sought to identify histone chaperones from two model plant species and investigated their phylogeny, domain architecture and transcriptional profiles to establish correlation between their expression patterns and potential role in stress physiology and plant development. RESULTS: Through comprehensive whole genome analyses of Arabidopsis and rice, we identified twenty-two and twenty-five genes encoding histone chaperones in these plants, respectively. These could be classified into seven different families, namely NAP, CAF1, SPT6, ASF1, HIRA, NASP, and FACT. Phylogenetic analyses of histone chaperones from diverse organisms including representative species from each of the major plant groups, yeast and human indicated functional divergence in NAP and CAF1C in plants. For the largest histone chaperone family, NAP, phylogenetic reconstruction suggested the presence of two distinct groups in plants, possibly with differing histone preferences. Further, to comment upon their physiological roles in plants, we analyzed their expression at different developmental stages, across various plant tissues, and under biotic and abiotic stress conditions using pre-existing microarray and qRT-PCR. We found tight transcriptional regulation of some histone chaperone genes during development in both Arabidopsis and rice, suggesting that they may play a role in genetic reprogramming associated with the developmental process. Besides, we found significant differential expression of a few histone chaperones under various biotic and abiotic stresses pointing towards their potential function in stress response. CONCLUSIONS: Taken together, our findings shed light onto the possible evolutionary trajectory of plant histone chaperones and present novel prospects about their physiological roles. Considering that the developmental process and stress response require altered expression of a large array of genes, our results suggest that some plant histone chaperones may serve a regulatory role by controlling the expression of genes associated with these vital processes, possibly via modulating chromatin dynamics at the corresponding genetic loci.

Genome wide identification of the immunophilin gene family in Leptosphaeria maculans: a causal agent of Blackleg disease in Oilseed Rape (Brassica napus).

Abstract Phoma stem canker (blackleg) is a disease of world-wide importance on oilseed rape (Brassica napus) and can cause serious losses for crops globally. The disease is caused by dothideomycetous fungus, Leptosphaeria maculans, which is highly virulent/aggressive. Cyclophilins (CYPs) and FK506-binding proteins (FKBPs) are ubiquitous proteins belonging to the peptidyl-prolyl cis/trans isomerase (PPIase) family. They are collectively referred to as immunophilins (IMMs). In the present study, IMM genes, CYP and FKBP in haploid strain v23.1.3 of L. maculans genome, were identified and classified. Twelve CYPs and five FKBPs were determined in total. Domain architecture analysis revealed the presence of a conserved cyclophilin-like domain (CLD) in the case of CYPs and FKBP_C in the case of FKBPs. Interestingly, IMMs in L. maculans also subgrouped into single domain (SD) and multidomain (MD) proteins. They were primarily found to be localized in cytoplasm, nuclei, and mitochondria. Homologous and orthologous gene pairs were also determined by comparison with the model organism Saccharomyces cerevisiae. Remarkably, IMMs of L. maculans contain shorter introns in comparison to exons. Moreover, CYPs, in contrast with FKBPs, contain few exons. However, two CYPs were determined as being intronless. The expression profile of IMMs in both mycelium and infected primary leaves of B. napus demonstrated their potential role during infection. Secondary structure analysis revealed the presence of atypical eight ß strands and two α helices fold architecture. Gene ontology analysis of IMMs predicted their significant role in protein folding and PPIase activity. Taken together, our findings for the first time present new prospects of this highly conserved gene family in phytopathogenic fungus.

Structural and biochemical characterization of the cytosolic wheat cyclophilin TaCypA-1.

Cyclophilins belong to a family of proteins that bind to the immunosuppressive drug cyclosporin A (CsA). Several members of this protein family catalyze the cis-trans isomerization of peptide bonds preceding prolyl residues. The present study describes the biochemical and structural characteristics of a cytosolic cyclophilin (TaCypA-1) cloned from wheat (Triticum aestivum L.). Purified TaCypA-1 expressed in Escherichia coli showed peptidyl-prolyl cis-trans isomerase activity, which was inhibited by CsA with an inhibition constant of 78.3 nM. The specific activity and catalytic efficiency (kcat/Km) of the purified TaCypA-1 were 99.06 ± 0.13 nmol s(-1) mg(-1) and 2.32 × 10(5) M(-1) s(-1), respectively. The structures of apo TaCypA-1 and the TaCypA-1-CsA complex were determined at 1.25 and 1.20 Šresolution, respectively, using X-ray diffraction. Binding of CsA to the active site of TaCypA-1 did not result in any significant conformational change in the apo TaCypA-1 structure. This is consistent with the crystal structure of the human cyclophilin D-CsA complex reported at 0.96 Å resolution. The TaCypA-1 structure revealed the presence of a divergent loop of seven amino acids (48)KSGKPLH(54) which is a characteristic feature of plant cyclophilins. This study is the first to elucidate the structure of an enzymatically active plant cyclophilin which shows peptidyl-prolyl cis-trans isomerase activity and the presence of a divergent loop.

Dissecting out the crosstalk between salinity and hormones in roots of Arabidopsis.

Phytohormones are chemical messengers that play a leading role in regulating the vital activity of plants, including transcription, posttranscriptional pre-mRNA splicing, translation, and posttranslational modifications by interacting with specific protein receptors. Plant hormones are synthesized in one tissue and act on specific target sites in other tissues at vanishingly low concentrations. High salinity is one of the main factors limiting Arabidopsis growth and productivity. In this study, phytohormones including abscisic acid, auxin, ethylene, and cytokinin responsive genes regulating salinity stress in Arabidopsis roots were monitored using microarray data. We identified phytohormone responsive genes on the basis of their expression pattern at genomic level at various time points. Using publicly available microarray data, we analyzed the effect of salt stress on the transcription of phytohormone responsive genes. Gene ontology (GO) analysis of phytohormone responsive genes showed their role in important biological processes such as signal transduction, hormone metabolism, biosynthetic process, and gene expression. Gene enrichment terms also reveal that transcription regulator activity is the main class of ABA responsive genes under salinity stress. We conclude that expression of ABA responsive genes involves induction of several transcription factors under salt stress treatment in Arabidopsis roots.