Contribution of arbuscular mycorrhizal symbiosis to alliviate stress caused by Nacobbus aberrans nematode

GARITA, SEBASTIÁN; RIPODAS, JUAN IGNACIO; RUSCITTI MARCELA; ARANGO, CECILIA; BERNARDO, VALERIA

Barcelona

Congreso; XV Spanish-Portuguese Congress of Plant Physiology; 2017

Sociedades Española y Portuguesa de Fisiología Vegetal

Nacobbus aberrans is a parasitic root-knot nematode that causes yield losses in horticultural crops across the Americas, even leading to the death of plants in the case of severe attacks. The products currently used for its control have a high economic cost, lack specificity and have a high degree of toxicity. Symbiosis with arbuscular mycorrhizal fungi (AMF) has been shown to have a protective effect against several soil pathogens. Plants of Solanum lycopersicum Cv. Platense both with and without mycorrhizal colonization by Funneliformis mosseae were cultivated in soil artificially inoculated and not inoculated with N. aberrans. Four months after the transplant, the plants were extracted and it could be observed that the mobile forms of N. aberrans had penetrated into the roots, destroying the cortical parenchyma, causing necrotic lesions, barking of the root and the death of rootlets. As a consequence of this damage in cell membranes, malondialdehyde levels were significantly higher (1.9 nmoles.g-1)in comparison to tests treatments where the pathogen was absent (1.2 nmoles.g1). In mycorrhizal plants, the number of lesions was significantly lower than in non-mycorrhizal plants. Adult females were hosted by the roots forming galls, breaking the continuity of conductive tissues and altering the normal flow of water. As a consequence, infected plants suffered water stress, leading to an increase in proline levels (↑ 50%), and a reduction of protein content (↓ 20%). In mycorrhizal plants, water stress indicators had significantly lower values than in non-mycorrhizal plants. In addition, the number of nematode eggs collected in mycorrhizal roots was 80% lower than in non-mycorrhizal plants, indicating that this practice is beneficial to both attenuating the stress caused by the pathogen and reducing its population.