Compounds Associated with Infection by the Root-Knot Nematode, Meloidogyne javanica, Influence the Ability of Infective Juveniles to Recognize Host Plants

• Published in: Journal of agricultural and food chemistry Vol. 68; no. 34; pp. 9100 - 9109
• Main Authors: Kihika, Ruth, Tchouassi, David P, Ng’ang’a, Margaret M, Hall, David R, Beck, John J, Torto, Baldwyn
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26.08.2020
• Subjects: Animals; Bioactive Constituents, Metabolites, and Functions; Host-Parasite Interactions; Lycopersicon esculentum - chemistry; Lycopersicon esculentum - metabolism; Lycopersicon esculentum - parasitology; Plant Diseases - parasitology; Plant Roots - chemistry; Plant Roots - metabolism; Plant Roots - parasitology; Tylenchoidea - growth & development; Tylenchoidea - physiology; Volatile Organic Compounds - chemistry; Volatile Organic Compounds - metabolism; root volatiles; Solanum lycopersicum; Meloidogyne javanica; chemotaxis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.0c03386

Plant root chemistry is altered by the parasitism of plant-parasitic nematodes (PPN). Here, we investigated the influence of the infective stage juveniles (J2) of Meloidogyne javanica in inducing tomato (Solanum lycopersicum) root volatiles and chemotactic effect on conspecifics. In olfactometer assays, J2 avoided the roots of 2-day infected plants but preferred 7-day-infected tomato compared to healthy plants. Chemical analysis showed a 2–7-fold increase in the amounts of monoterpenes emitted from tomato roots infected with M. javanica relative to healthy roots. In further bioassays, the monoterpenes β-pinene, (+)-(2)-carene, α-phellandrene, and β-phellandrene differentially attracted (51–87%) J2 relative to control. Concurrent reduction and increase in the levels of methyl salicylate and (Z)-methyl dihydrojasmonate, respectively, in the root volatiles reduced J2 responses. These results demonstrate that the host plant can alter its root volatile composition to inhibit PPN attack. The observed plant-produced inhibition of J2 warrants further investigation as a potential management tool for growers.