Project description:In this study, we present a first proteomic overview of macadamia nut using a label-free shotgun proteomic approach and prediction of their proteins with potential allergenic activity and cross-reactivity via an in silico analysis. The defense response proteins were the most abundant group of proteins and accounted for 24% of the total abundance. The vicilin-like macadamia antimicrobial peptides 2-3 (MiAMP2) was the most abundant protein. The cascading of amino acid and carbohydrate metabolic pathways in macadamia nut were constructed and proposed for the first time. The in silico analysis revealed seed storage proteins (conglutins and vicilins), rubber elongation factor proteins, phosphate binding proteins, and detoxifying methylglyoxalases among others as proteins with allergenic and cross-reactive potential. The label-free shotgun proteomics study revealed valuable insight into the genetic and biological makeup of macadamia nut and potential proteins with predictive allergenic activity and cross-reactivity. Integration of genomics with the proteomic data will be indispensable for future molecular characterization of macadamia including allergens.
Project description:In plants, juvenile to adult phase transition is regulated by the sequential activity of two microRNAs: miR156 and miR172. A decline in miR156 and increase in miR172 abundance is associated with phase transition. There is very limited information on phase transition in economically important horticultural tree crops, which have a significantly long vegetative phase affecting fruit bearing. Here we profiled various molecular cues known to be involved in phase transition and flowering, including the microRNAs miR156 and miR172, in three horticultural tree crops avocado (Persea americana), mango (Mangifera indica) and macadamia (Macadamia integrifolia). We observed that miR156 expression decreases as these trees age and can potentially be used as a juvenility marker. Consistent with findings in annual plants, we also observed conserved regulation of the miR156-SPL3/4/5 regulatory module in these genetically distant tree crops, suggesting that this pathway may play a highly conserved role in vegetative identity. Meanwhile, the abundance of miR172 and its target AP2-like genes, as well as the accumulation level of SPL9 transcripts, were not related with plant age in these crops except in avocado where miR172 expression increased steadily. Finally, we demonstrate that various floral genes, including AP1 and SOC1 were upregulated in the reproductive phase and can be used as potential markers for the reproductive phase transition. Overall, this study provides an insight into the molecular associations of juvenility and phase transition in horticultural trees where crop breeding and improvement is encumbered by long juvenile phases.