Molecular mechanism of poisoning to honeybees (Apis mellifera L.) after ingestion of Camellia oleifera nectar

[Display omitted] •Poisoning occurred as soon as 0.5 h after bee feeding Camellia oleifera nectar.•All bees died within 4 h of exposure to Camellia oleifera nectar.•NAD+-dependent protein deacetylase, prolongs cell lifespan, is down-regulaed.•The enzyme caspase7, which ensures orderly cell apoptosis, is down-regulaed.•Rapid and disorderly death of cells contribute towards death of the bees. To explore the molecular mechanism of honeybees (Apis mellifera L.) poisoning death by ingestion of Camellia oleifera nectar, feeding experiments were designed to investigate the poisoning effects. Observed the development process of poisoning symptoms, and collected bees at key experimental nodes for transcriptome sequencing analysis. The results showed that the first poisoning symptom was observed within 0.5 h after ingestion of Camellia oleifera nectar, with death occurring as early as 2 h post-ingestion and all honey bees dying within 4 h. There were four stages in the development of poisoning symptoms: normal flying, crawling (abdominal swelling, inability to fly normally), fluttering (inability to crawl normally), and death. Transcriptome sequencing analyzed the causes of poisoning death indicated that honey bee poisoning occurred with the transduction of dietary restriction signals into cells, resulting in the down-regulated expression gene elements that ensure cell health and inhibit apoptosis, including intracellular NAD+-dependent protein deacetylase sirtuin 1, insulin-like growth factor 1, and heat shock proteins. At the same time, the expression of cysteinyl aspartate specific proteinase 7, which protects programmed cell apoptosis, was also downregulated, resulting in the rapid and disorderly deaths of a large number of cells in individuals in a short period of time, and eventually leading to bees fatality.