Project description:'Candidatus Liberibacter asiaticus' (CLas), the bacterial pathogen associated with citrus greening disease, is transmitted by Diaphorina citri, the Asian citrus psyllid. Interactions among D. citri and its microbial endosymbionts, including 'Candidatus Profftella armatura', are likely to impact transmission of CLas. We used quantitative mass spectrometry to compare the proteomes of CLas(+) and CLas(-) populations of D. citri, and found that proteins involved in polyketide biosynthesis by the endosymbiont Profftella were up-regulated in CLas(+) insects. Mass spectrometry analysis of the Profftella polyketide diaphorin in D. citri metabolite extracts revealed the presence of a novel diaphorin-related polyketide and the ratio of these two polyketides was changed in CLas(+) insects. Insect proteins differentially expressed between CLas(+) and CLas(-) D. citri included defense and immunity proteins, proteins involved in energy storage and utilization, and proteins involved in endocytosis, cellular adhesion, and cytoskeletal remodeling which are associated with microbial invasion of host cells. Insight into the metabolic interdependence between the insect vector, its endosymbionts, and the citrus greening pathogen reveals novel opportunities for control of this disease, which is currently having a devastating impact on citrus production worldwide.
Project description:Experimental data about gene functions curated from the primary literature have enormous value for research scientists in understanding biology. Using the Gene Ontology (GO), manual curation by experts has provided an important resource for studying gene function, especially within model organisms. Unprecedented expansion of the scientific literature and validation of the predicted proteins have increased both data value and the challenges of keeping pace. Capturing literature-based functional annotations is limited by the ability of biocurators to handle the massive and rapidly growing scientific literature. Within the community-oriented wiki framework for GO annotation called the Gene Ontology Normal Usage Tracking System (GONUTS), we describe an approach to expand biocuration through crowdsourcing with undergraduates. This multiplies the number of high-quality annotations in international databases, enriches our coverage of the literature on normal gene function, and pushes the field in new directions. From an intercollegiate competition judged by experienced biocurators, Community Assessment of Community Annotation with Ontologies (CACAO), we have contributed nearly 5,000 literature-based annotations. Many of those annotations are to organisms not currently well-represented within GO. Over a 10-year history, our community contributors have spurred changes to the ontology not traditionally covered by professional biocurators. The CACAO principle of relying on community members to participate in and shape the future of biocuration in GO is a powerful and scalable model used to promote the scientific enterprise. It also provides undergraduate students with a unique and enriching introduction to critical reading of primary literature and acquisition of marketable skills.
Project description:The title compound C22H39NO9·CH3OH [systematic name: (S)-N-((S)-{(2S,4R,6R)-6-[(S)-2,3-di-hydroxy-prop-yl]-4-hy-droxy-5,5-di-methyl-tetra-hydro-2H-pyran-2-yl}(hy-droxy)meth-yl)-2-hy-droxy-2-[(2R,5R,6R)-2-meth-oxy-5,6-dimeth-yl-4-methyl-ene-tetra-hydro-2H-pyran-2-yl]acetamide methanol monosolvate], was isolated from the Asian citrus psyllid, Diaphorina citri Kuwayama, and crystallizes in the space group P21. 'Candidatus Profftella armatura' a bacterial endosymbiont of D. citri, biosynthesizes diaphorin, which is a hybrid polyketide-nonribosomal peptide comprising two highly substituted tetra-hydro-pyran rings joined by an N-acyl aminal bridge [Nakabachi et al. (2013 ▸). Curr. Biol.23, 1478-1484]. The crystal structure of the title compound establishes the complete relative configuration of diaphorin, which agrees at all nine chiral centers with the structure of the methanol monosolvate of the di-p-bromo-benzoate derivative of pederin, a biogenically related compound whose crystal structure was reported previously [Furusaki et al. (1968 ▸). Tetra-hedron Lett.9, 6301-6304]. Thus, the absolute configuration of diaphorin is proposed by analogy to that of pederin.
Project description:The Asian citrus psyllid (Diaphorina citri) is the insect vector responsible for the worldwide spread of 'Candidatus Liberibacter asiaticus' (CLas), the bacterial pathogen associated with citrus greening disease. Developmental changes in the insect vector impact pathogen transmission, such that D. citri transmission of CLas is more efficient when bacteria are acquired by nymphs when compared with adults. We hypothesize that expression changes in the D. citri immune system and commensal microbiota occur during development and regulate vector competency. In support of this hypothesis, more proteins, with greater fold changes, were differentially expressed in response to CLas in adults when compared with nymphs, including insect proteins involved in bacterial adhesion and immunity. Compared with nymphs, adult insects had a higher titre of CLas and the bacterial endosymbionts Wolbachia, Profftella and Carsonella. All Wolbachia and Profftella proteins differentially expressed between nymphs and adults are upregulated in adults, while most differentially expressed Carsonella proteins are upregulated in nymphs. Discovery of protein interaction networks has broad applicability to the study of host-microbe relationships. Using protein interaction reporter technology, a D. citri haemocyanin protein highly upregulated in response to CLas was found to physically interact with the CLas coenzyme A (CoA) biosynthesis enzyme phosphopantothenoylcysteine synthetase/decarboxylase. CLas pantothenate kinase, which catalyses the rate-limiting step of CoA biosynthesis, was found to interact with a D. citri myosin protein. Two Carsonella enzymes involved in histidine and tryptophan biosynthesis were found to physically interact with D. citri proteins. These co-evolved protein interaction networks at the host-microbe interface are highly specific targets for controlling the insect vector responsible for the spread of citrus greening.
Project description:Insect-derived baculoviruses have emerged as versatile and safe workhorses of biotechnology. Baculovirus expression vectors (BEVs) have been applied widely for crop and forest protection, as well as safe tools for recombinant protein production in insect cells. However, BEVs ability to efficiently transduce noninsect cells is still relatively poorly recognized despite the fact that efficient baculovirus-mediated in vitro and ex vivo gene delivery into dormant and dividing vertebrate cells of diverse origin has been described convincingly by many authors. Preliminary proof of therapeutic potential has also been established in preclinical studies. This review summarizes the advantages and current status of baculovirus-mediated gene delivery. Stem cell transduction, preclinical animal studies, tissue engineering, vaccination, cancer gene therapy, viral vector production, and drug discovery are covered.
Project description:The European Nucleotide Archive (ENA; http://www.ebi.ac.uk/ena) is a repository for the submission, maintenance and presentation of nucleotide sequence data and related sample and experimental information. In this article we report on ENA in 2015 regarding general activity, notable published data sets and major achievements. This is followed by a focus on sustainable biocuration of functional annotation, an area which has particularly felt the pressure of sequencing growth. The importance of functional annotation, how it can be submitted and the shifting role of the biocurator in the context of increasing volumes of data are all discussed.
Project description:Stable associations between plants and microbes are critical to promoting host health and productivity. The objective of this work was to test the hypothesis that restructuring of the core microbiota may be associated with the progression of huanglongbing (HLB), the devastating citrus disease caused by Liberibacter asiaticus, Liberibacter americanus, and Liberibacter africanus The microbial communities of leaves (n = 94) and roots (n = 79) from citrus trees that varied by HLB symptom severity, cultivar, location, and season/time were characterized with Illumina sequencing of 16S rRNA genes. The taxonomically rich communities contained abundant core members (i.e., detected in at least 95% of the respective leaf or root samples), some overrepresented site-specific members, and a diverse community of low-abundance variable taxa. The composition and diversity of the leaf and root microbiota were strongly associated with HLB symptom severity and location; there was also an association with host cultivar. The relative abundance of Liberibacter spp. among leaf microbiota positively correlated with HLB symptom severity and negatively correlated with alpha diversity, suggesting that community diversity decreases as symptoms progress. Network analysis of the microbial community time series identified a mutually exclusive relationship between Liberibacter spp. and members of the Burkholderiaceae, Micromonosporaceae, and Xanthomonadaceae This work confirmed several previously described plant disease-associated bacteria, as well as identified new potential implications for biological control. Our findings advance the understanding of (i) plant microbiota selection across multiple variables and (ii) changes in (core) community structure that may be a precondition to disease establishment and/or may be associated with symptom progression.IMPORTANCE This study provides a comprehensive overview of the core microbial community within the microbiomes of plant hosts that vary in extent of disease symptom progression. With 16S Illumina sequencing analyses, we not only confirmed previously described bacterial associations with plant health (e.g., potentially beneficial bacteria) but also identified new associations and potential interactions between certain bacteria and an economically important phytopathogen. The importance of core taxa within broader plant-associated microbial communities is discussed.
Project description:Citrus huanglongbing (HLB) is a severe problem for citrus cultivation. The disease management programs benefit from improved field tools suitable for surveying the ACP vector (Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae)) and the associated pathogen. In the present study, we utilize three-dimensional (3D) printers and design tools to develop traps that can capture and preserve ACPs. Three novel, 3D-printed traps were designed and evaluated: stem trap, and cylinder traps 1 and 2. The traps and yellow sticky cards were deployed weekly for 8 months in 2 non-commercial citrus groves in Florida; in California, the traps were evaluated for 12 months in field cages and 4 citrus groves. The stem traps captured lower numbers of ACPs at all experimental sites compared to the cylinder traps. Capture rates in the cylinder traps were comparable to the sticky trap, making the device a viable tool for monitoring field ACPs. The two main advantages of using the reusable 3D traps over standard methods of ACP and HLB surveys include dynamic sampling that can be conducted year-round and the capture of ACPs that can be preserved and tested. Improved trapping may facilitate quick management decisions and mitigate HLB.
Project description:Citrus Greening or Huanglongbing (HLB) is a disease of citrus, causing high reduction in citrus production and is transmitted by the Asian citrus psyllid Diaphorina citri Kuwayama vectoring a phloem-limited bacterium Candidatus Liberibacter sp. We report research results using crowdsourcing challenge strategy identifying potential gene targets in D. citri to control the insect using RNA interference (RNAi). From 63 submitted sequences, 43 were selected and tested by feeding them to D. citri using artificial diet assays. After feeding on artificial diet, the three most effective dsRNAs causing 30% mortality above control silenced genes expressing iron-sulfur cluster subunit of the mitochondrial electron transport chain complex (Rieske), heme iron-binding terminal oxidase enzyme (Cytochrome P450) and tetrahydrobiopterin (BH4) pathway enzyme (Pterin 4α-Carbinolamine Dehydratase). These sequences were cloned into a citrus phloem-limited virus (Citrus tristeza virus, CTV T36) expressing dsRNA against these target genes in citrus. The use of a viral mediated "para-transgenic" citrus plant system caused higher mortality to adult D. citri than what was observed using artificial diet, reaching 100% when detached citrus leaves with the engineered CTV expressing dsRNA were fed to adult D. citri. Using this approach, a virus-induced gene silencing (VIGS) can be used to test future transgenic cultivars before genetically engineering citrus. RNA Seq analysis after feeding D. citri CTV-RIE on infected leaves identified transcriptionally modified genes located upstream and downstream of the targeted RIE gene. These genes were annotated showing that many are associated with the primary function of the Rieske gene that was targeted by VIGS.
Project description:Commercial sweet orange cultivars lack resistance to Huanglongbing (HLB), a serious phloem limited bacterial disease that is usually fatal. In order to develop sustained disease resistance to HLB, transgenic sweet orange cultivars 'Hamlin' and 'Valencia' expressing an Arabidopsis thaliana NPR1 gene under the control of a constitutive CaMV 35S promoter or a phloem specific Arabidopsis SUC2 (AtSUC2) promoter were produced. Overexpression of AtNPR1 resulted in trees with normal phenotypes that exhibited enhanced resistance to HLB. Phloem specific expression of NPR1 was equally effective for enhancing disease resistance. Transgenic trees exhibited reduced diseased severity and a few lines remained disease-free even after 36 months of planting in a high-disease pressure field site. Expression of the NPR1 gene induced expression of several native genes involved in the plant defense signaling pathways. The AtNPR1 gene being plant derived can serve as a component for the development of an all plant T-DNA derived consumer friendly GM tree.