AsianScientist (Jul. 23, 2025) – Living on the roots of Solanaceae plants like potatoes and tomatoes, the potato cyst nematode causes yield-loss and root damage. At the end of their life cycle, the nematode body forms a cyst, encasing eggs that can lay dormant in the soil for up to 20 years.
Cyst nematode eggs hatch only when they detect hatching factors – molecules secreted by the roots of their host plants. For potato cyst nematodes, these are solanoeclepin B (SEB) and solanoeclepin A (SEA).
“If we apply hatching factors to agricultural soils before planting the plants and so induce the parasites to hatch prematurely, this so-called ‘suicide hatching’ might be effective parasite control,” said Mizutani Masaharu, Professor of Phytochemistry at Kobe University. “However, this class of chemicals is difficult to identify because they are secreted in very small amounts.”
Mizutani and his team previously found that plants only produce SEB, which microorganisms in the soil convert into SEA. “When we measured the process’ reaction rate, we noticed that the amount of SEB in the soil initially increased when we applied tomato root secretions to soils. This led us to hypothesise that there must be another, hitherto unknown molecule that the plants had produced and secreted,” said Mizutani. “In the soils, we conjectured, soil microbes converted it into SEB and then further into SEA.”
The researchers have now published the discovery of solanoeclepin C (SEC), their hypothesised molecule.
SEC is secreted 20 times more by the plants compared to SEB, but does not act as a hatching factor for parasites. Instead, it decays in the soil to form SEB in a process expedited by soil microorganisms.
“This indicates that maybe it is the secretion of SEC that is of physiological relevance to the plants, but through the chemical’s conversion to SEB and further to SEA, the parasites are then activated. This is the first time that this kind of three-way relationship has been found for this class of chemicals,” Mizutani said.
The reason why plants secrete these chemicals remain unclear. “At first glance, a hatching factor seems to be a component that has only unfavourable activity for a plant and it’s curious why they would produce it. But we are looking forward to future work clarifying the beneficial effects this class of chemicals has for the plants,” said Mizutani.
Plants produce chemicals for various purposes, including attracting soil microorganisms for symbiotic exchanges of nutrients. Gene expression analysis on tomatoes revealed one possible cause for secreting solanoeclepins.
“Trying different environmental conditions for the plants, we found that they secreted SEC, and to a much lower extent SEB, especially when they are starved for nitrogen or phosphorus, which are essential nutrients,” said Mizutani.
The discovery of SEC brings researchers closer to developing practical applications of hatching factors in sustainable agriculture, where they could induce ‘suicide hatching’ of parasites before crops are planted. However, the synthetic production of solanoeclepins is currently impractical for agricultural use.
Mizutani explained, “This class of chemicals is structurally complex and thus difficult to make. But if we keep looking, we might find an equivalent that has similar effects and is easier to produce.”
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Source: Kobe University Image: Wikimedia Commons
This article can be found at Solanoeclepin C, a root-secreted molecule converted by rhizosphere microbes to hatching factors for potato cyst nematodes
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