Responses of infective juveniles of the soybean cyst nematode (Heterodera glycines) and the root-knot nematodes (Meloidogyne hapla, M. incognita) to amino acids

What is it about?

Root-knot nematodes and cyst nematodes are top two economically important and soil-borne plant parasitic nematodes in the world. Root exudates are critical to a plant’s responses to abiotic and biotic exposures, and its interactions within the rhizosphere. Among these root exudate metabolites are chemical signals that, through plant parasitic nematode chemoreception, affect nematode chemotaxis and host infection. Among primary metabolites in root exudates, amino acids are the second most abundant after sugars. However, it remains unknown if amino acids are associated with nematode chemotaxis. Using the powerful Pluronic gel in which nematodes move in a three-dimensions as in the soil compared with 2-dimensions of the agar gel, first time we examined and compared nematode attraction, mortality and behavior in response to 15 amino acids composing 4 types of amino acid (Polar, Nonpolar, Polar acidic, Polar basic) and determined the interactions between amino acids and pH in nematode behaviors. The results indicated acidic or basic AAs play roles in combination with pH and nematode species for nematode attraction. Nematode species, AA types, AA dose, pH affect nematode chemotaxis and mortality. The knowledge of AA attractiveness to plant parasitic nematodes gains more understanding of early ecological relationship between parasitic nematodes and plants and will help to develop a promising way to explore new control strategies against plant-parasitic nematodes.

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