Abstract
The oyster mushroom Pleurotus ostreatus is a nematophagous basidiomycete that produces toxins to paralyze nematodes. We previously reported that P. ostreatus triggers a massive calcium influx and rapid cell necrosis in the neuromuscular system of C. elegans via its sensory cilia. However, how do the mushroom hyphae trigger rapid cell necrosis remains unclear. Here, we show that P. ostreatus induced calcium influx in the mitochondrial matrix, resulting in massive mitochondria enlargement within five minutes of hyphal contact. In addition, the ATP level dropped promptly in the pharyngeal muscle cells of the paralyzed nematodes. Moreover, we observed a calcium wave propagated across the mitochondria of hypodermis. Mutants exhibited muscle contraction defects restricted the calcium wave, suggesting that body wall muscle contraction contributed to the propagation of calcium wave in hypodermis. Furthermore, C. elegans mutants with disrupted ER-mitochondria contacts decreased the calcium influx in the mitochondria of pharyngeal muscle cells. Our findings illustrate that Pleurotus toxins trigger drastically ion imbalance and disrupt mitochondrial function, leading to energy failure and cell necrosis throughout the entire animal.
