Nut-based milks and yogurts are gaining popularity, but may not offer the same benefits as dairy yogurts to consumers
Cashew nuts often cause severe allergic reactions, and cashew nut allergens are ...stable to several types of processing. To compare its characteristics to dairy yogurt and characterize the effects of fermentation on the Ana o 1-3 cashew nut allergens, a commercial yogurt made from cashew nuts (Cashewgurt) was evaluated for microbiological, physiochemical, and immunological properties. Average counts for lactobacilli and
were greater than 10 million colony forming units per milliliter, indicating the capacity to provide a health benefit. Cashewgurt pH and viscosity values were comparable to cow milk yogurts, and it was off white in color. SDS-PAGE analysis indicated a clear reduction in Ana o 1 and 2, and immuno-assay with polyclonal anti-cashew IgG antibody and cashew-allergic IgE indicated an overall reduction in allergen content. In contrast, SDS-PAGE, mass spectrometry, immunoblot, and ELISA all revealed that Ana o 3 was relatively unaffected by the fermentation process. In conclusion, Ana o 1 and Ana o 2 are sensitive to degradation, while Ana o 3 survives lactic acid bacterial fermentation during yogurt production. The analysis presented here indicates that cashew nut yogurt is not suitable for those with cashew nut allergy.
Fermentation alters the protein content and composition of foods. To characterize fungal catabolism of peanut proteins, defatted peanut flour was fermented by Rhizopus oryzae (R. oryzae) for up to ...48 h and evaluated by SDS-PAGE, mass spectrometry, and antibody binding. A clear change in peanut protein migration was observed by SDS-PAGE after 16 h of fermentation. Mass spectrometric analysis indicated changes in allergen peptides and R. oryzae proteins. Several low molecular weight allergen fragments produced during fermentation were identified by mass spectrometry. Immunoassays using anti-peanut allergen antibodies demonstrated reduced allergen content as early as 16 h of fermentation. However, ELISA with peanut allergic IgE indicated only slightly reduced allergen binding even after 48 h. These results indicate that while R. oryzae fermentation efficiently metabolizes peanut allergens, significant IgE binding remains in lower molecular mass peptides, and therefore R. oryzae fermented peanut products would not be safe for peanut allergic individuals.
•R. oryzae metabolizes peanut allergens into peptide fragments.•Peanut allergen reduction varies depending upon the specific allergen.•IgE-peanut allergen binding is only slightly reduced by R. oryzae fermentation.•R. oryzae fermented peanut is not safe for individuals with peanut allergy.
Pseudomonas syringae is the most widespread bacterial pathogen in plants. Several strains of P. syringae produce a phytotoxin, coronatine (COR), which acts as a jasmonic acid mimic and inhibits plant ...defense responses and contributes to disease symptom development. In this study, we found that COR inhibits early defense responses during nonhost disease resistance. Stomatal closure induced by a nonhost pathogen, P. syringae pv. tabaci, was disrupted by COR in tomato epidermal peels. In addition, nonhost HR cell death triggered by P. syringae pv. tabaci on tomato was remarkably delayed when COR was supplemented along with P. syringae pv. tabaci inoculation. Using isochorismate synthase (ICS)-silenced tomato plants and transcript profiles of genes in SA- and JA-related defense pathways, we show that COR suppresses SA-mediated defense during nonhost resistance.
Pecan (
) nuts are an economically valuable crop native to the United States and Mexico. A proteomic summary from two pecan cultivars at multiple time points was used to compare protein accumulation ...during pecan kernel development. Patterns of soluble protein accumulation were elucidated using qualitative gel-free and label-free mass-spectrometric proteomic analyses and quantitative (label-free) 2-D gel electrophoresis. Two-dimensional (2-D) gel electrophoresis distinguished a total of 1267 protein spots and shotgun proteomics identified 556 proteins. Rapid overall protein accumulation occurred in mid-September during the transition to the dough stage as the cotyledons enlarge within the kernel. Pecan allergens Car i 1 and Car i 2 were first observed to accumulate during the dough stage in late September. While overall protein accumulation increased, the presence of histones diminished during development. Twelve protein spots accumulated differentially based on 2-D gel analysis in the weeklong interval between the dough stage and the transition into a mature kernel, while eleven protein spots were differentially accumulated between the two cultivars. These results provide a foundation for more focused proteomic analyses of pecans that may be used in the future to identify proteins that are important for desirable traits, such as reduced allergen content, improved polyphenol or lipid content, increased tolerance to salinity, biotic stress, seed hardiness, and seed viability.
Parasitic weeds of the family Orobanchaceae attach to the roots of host plants via haustoria capable of drawing nutrients from host vascular tissue. The connection of the haustorium to the host marks ...a shift in parasite metabolism from autotrophy to at least partial heterotrophy, depending on the level of parasite dependence. Species within the family Orobanchaceae span the spectrum of host nutrient dependency, yet the diversity of parasitic plant metabolism remains poorly understood, particularly during the key metabolic shift surrounding haustorial attachment. Comparative profiling of major metabolites in the obligate holoparasite
and the facultative hemiparasite
before and after attachment to the hosts revealed several metabolic shifts implicating remodeling of energy and amino acid metabolism. After attachment, both parasites showed metabolite profiles that were different from their respective hosts. In
, prominent changes in metabolite profiles were also associated with transitioning between different tissue types before and after attachment, with aspartate levels increasing significantly after the attachment. Based on the results from
N labeling experiments, asparagine and/or aspartate-rich proteins were enriched in host-derived nitrogen in
. These results point to the importance of aspartate and/or asparagine in the early stages of attachment in these plant parasites and provide a rationale for targeting aspartate-family amino acid biosynthesis for disrupting the growth of parasitic weeds.
Genome-enabled biotechnologies have the potential to accelerate breeding efforts in long-lived perennial crop species. Despite the transformative potential of molecular tools in pecan and other ...outcrossing tree species, highly heterozygous genomes, significant presence-absence gene content variation, and histories of interspecific hybridization have constrained breeding efforts. To overcome these challenges, here, we present diploid genome assemblies and annotations of four outbred pecan genotypes, including a PacBio HiFi chromosome-scale assembly of both haplotypes of the 'Pawnee' cultivar. Comparative analysis and pan-genome integration reveal substantial and likely adaptive interspecific genomic introgressions, including an over-retained haplotype introgressed from bitternut hickory into pecan breeding pedigrees. Further, by leveraging our pan-genome presence-absence and functional annotation database among genomes and within the two outbred haplotypes of the 'Lakota' genome, we identify candidate genes for pest and pathogen resistance. Combined, these analyses and resources highlight significant progress towards functional and quantitative genomics in highly diverse and outbred crops.
Nonphotosynthetic holoparasites exploit flexible targeting of phylloquinone biosynthesis to facilitate plasma membrane redox signaling. Phylloquinone is a lipophilic naphthoquinone found ...predominantly in chloroplasts and best known for its function in photosystem I electron transport and disulfide bridge formation of photosystem II subunits. Phylloquinone has also been detected in plasma membrane (PM) preparations of heterotrophic tissues with potential transmembrane redox function, but the molecular basis for this noncanonical pathway is unknown. Here, we provide evidence of PM phylloquinone biosynthesis in a nonphotosynthetic holoparasite Phelipanche aegyptiaca. A nonphotosynthetic and nonplastidial role for phylloquinone is supported by transcription of phylloquinone biosynthetic genes during seed germination and haustorium development, by PM-localization of alternative terminal enzymes, and by detection of phylloquinone in germinated seeds. Comparative gene network analysis with photosynthetically competent parasites revealed a bias of P. aegyptiaca phylloquinone genes toward coexpression with oxidoreductases involved in PM electron transport. Genes encoding the PM phylloquinone pathway are also present in several photoautotrophic taxa of Asterids, suggesting an ancient origin of multifunctionality. Our findings suggest that nonphotosynthetic holoparasites exploit alternative targeting of phylloquinone for transmembrane redox signaling associated with parasitism.
Parasitic weeds of the family Orobanchaceae attach to the roots of host plants via haustoria capable of drawing nutrients from host vascular tissue. Species in this family span the spectrum of host ...nutrient dependency, allowing comparisons that provide insight into parasite adaptation. A key aspect of this is the relationship between parasite metabolism and the metabolite profile of its host. To what extent does the metabolite profile of the parasite depend on that of the host? Do parasites that differ in host-dependency also differ in their metabolism or do they use common metabolic strategies? These questions were addressed using comparative profiling of primary metabolites to gain insight into carbon and nitrogen assimilation by the obligate holoparasite Phelipanche aegyptiaca and the facultative hemiparasite Triphysaria versicolor. First, metabolite profiles of these parasites and their hosts were compared during the key life stages before and after haustorial attachment. Second, the impact of specific variations in host metabolism was analyzed for P. aegyptiaca growing on Arabidopsis thaliana hosts that had mutations in amino acid metabolism but otherwise identical genetic backgrounds. Comparison of P. aegyptiaca and T. versicolor metabolite profiles identified substantial differences in the stages spanning the transition from pre-haustorial development through post-haustorial feeding. Each parasite species is distinct from the other and from their hosts. For parasites growing on host lines that differ in amino acid content, the size of P. aegyptiaca tubercles decreased when grown on the aap6 mutant line, which has decreased levels of asparagine in the phloem sap compared to the wild type. However, altered amino acid levels in other lines did not impact P. aegyptiaca growth, indicating that this parasite has ability to compensate for variation in host metabolic composition. This research highlights the importance of aspartate and asparagine to early post-attachment metabolism in both P. aegyptiaca and T. versicolor and through host deficiencies possibly associated with decreased growth in P. aegyptiaca. Overall, this work provides insights both into the metabolism of parasitic plants and lays the foundation for the development of new metabolism-based control strategies.
Ph. D.
Parasitic weeds of the plant family Orobanchaceae attach to the roots of host plants via haustoria. Parasite haustoria embed into the host plant and are capable of drawing nutrients from host vascular tissue. Species in this family span the spectrum of the extent to which a parasitic plant may depend on its host for nutrients. This allows comparisons that provide insight into the ways in which parasites adapt. A key aspect of this is the relationship between the metabolite profile of the parasite and the metabolite profile of the host. To what extent does the metabolite profile of the parasite depend on that of the host? Do parasites that differ in host-dependency also differ in their metabolism or do they use common metabolic strategies? These questions were addressed using comparative profiling of primary metabolites to gain insight into carbon and nitrogen assimilation by the obligate parasite Phelipanche aegyptiaca (which cannot perform photosynthesis) and the facultative parasite Triphysaria versicolor (which can perform photosynthesis). First, metabolite profiles of these parasites and their hosts were compared during the key life stages before and after haustorial attachment. Second, the impact of specific variations in host metabolism was analyzed for P. aegyptiaca growing on Arabidopsis thaliana hosts. These hosts had mutations in enzymes related to amino acid metabolism but otherwise identical genetic backgrounds. Comparison of P. aegyptiaca and T. versicolor metabolite profiles identified substantial differences in the stages spanning the transition from pre-haustorial development through post-haustorial feeding. Each parasite species is distinct from the other and from their hosts. For parasites growing on host lines that differ in amino acid content, the size of P. aegyptiaca tubercles decreased when grown on the aap6 mutant line, which has decreased levels of asparagine in the phloem sap compared to the wild type. However, altered amino acid levels in other lines did not impact P. aegyptiaca growth, indicating that this parasite has ability to compensate for variation in host metabolic composition. Overall, this work provides insights both into the metabolism of parasitic plants and lays the foundation for the development of new metabolism-based control strategies.
PDF
