Project description:Disease outbreaks devastate Pyropia aquaculture farms every year. The three most common and serious diseases are Olpidiopsis blight and red-rot disease caused by oomycete pathogens and green-spot disease caused by PyroV1 virus. We hypothesized that a basic genetic profile of molecular defenses will be revealed by comparing and analyzing genetic response of Pyropia tenera against the above three pathogens. RNAs isolated from infected thalli were hybridized onto an oligochip containing 15,115 primers designed from P. tenera ESTs. Microarray profiles of the three diseases were compared and interpreted together with histochemical observation. Massive amounts of reactive oxygen species (ROS) were accumulated in P. tenera cells exposed to oomycete pathogens. Heat shock genes and serine proteases were the most highly upregulated genes in all infection experiments. Genes involved in RNA metabolism, ribosomal proteins and antioxidant metabolism were also highly upregulated. Genetic profiles of P. tenera in response to pathogens were most similar between the two biotrophic pathogens, Olpidiopsis pyropiae and PyroV1 virus. A group of plant R-gene homologues were specifically regulated against each pathogen. Our results suggested that disease resistance of P. tenera consist of a general and constitutive defense and a genetic toolkit against specific pathogen.
Project description:Porphyra/Pyropia seaweeds are promising sources for functional foods development, offering a rich macro- and micronutrient profiles. In New Zealand (NZ), endemic Porphyra/Pyropia species (karengo), exhibit considerable variability driven by geography, seasonality, and climate, which may influence their nutritional quality. Despite their use as traditional foods, the NZ Porphyra/Pyropia remain underutilized commercially, in part due to the lack of biomolecular characterisation, particularly their bioactive protein components, hindering evidence-based species selection for seaweed farming commercialisation and functional food development. This study presents the first proteomic characterization of three NZ Porphyra/Pyropia species: Pyropia virididentata, Pyropia cinnamomea, and Porphyra GRB complex. Mass spectrometry-based proteomics analysis identified differences in the phycobiliprotein composition among the species, with the Porphyra GRB complex containing higher levels of phycocyanin. Using the protein sequence information, in silico gastrointestinal digestion analysis predicted that phycobiliproteins from NZ Porphyra/Pyropia seaweeds can potentially release bioactive peptides capable of inhibiting angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) activities. Sequence-based allergenicity prediction indicated possible cross-reactivity between NZ Porphyra/Pyropia β-phycoerythrin and β-phycocyanin against the β-phycocyanin allergen from spirulina, which is associated with a low incidence of allergy. Proximate analysis revealed that NZ Porphyra/Pyropia seaweeds have high protein (26–30.2 %) and carbohydrate (48.3–50.9 %) contents, and low fat and free sugar levels. Amino acid profiling further showed that NZ Porphyra/Pyropia seaweeds are relatively rich in sulphur-containing amino acids and umami-associated amino acids. Overall, these findings highlight the potential of NZ Porphyra/Pyropia seaweeds as a novel plant-based protein source for functional food applications.