Fitonematoides em videira e pessegueiro: caracterização de espécies de Mesocriconema e Pratylenchus, reação de porta-enxertos, interação com Ilyonectria macrodidyma e primeiro relato de Meloidogyne morocciensis em pessegueiro no Brasil

Abstract

A problem of complex etiology, Grapevine Decline Disease (GDD), has become a notable obstacle to viticulture, causing great concern to producers. In recent surveys, high populations of ring nematode (Mesocriconema xenoplax) and root lesion nematode (Pratylenchus brachyurus) associated with GDD have been reported. The involvement of these plant parasitic nematodes in the GDD still needs to be better studied, especially in interaction with other pathogens, such as the fungus Ilyonectria macrodidyma, which causes the black foot in grapevines. Thus, the aims of this study were: a) identify the nematode community and to characterize Mesocriconema species associated with vineyards with symptoms of GDD in southern Brazil; b) to evaluate the reaction of rootstocks to M. xenoplax and P. brachyurus; d) to study the interaction among M. xenoplax, P. brachyurus, I. macrodidyma and different grapevine genotypes and e) report the occurrence of a new species of Meloidogyne parasitizing peach trees in Brazil. Three species of Mesocriconema were identified in the states of Santa Catarina and Rio Grande do Sul, including M. xenoplax, M. curvatum and M. rusticum. However, new protocols for amplification of mtCOI need to be tested for Criconematids. The rootstocks 548-44, IBCA-125 and VR 043-43 were resistant and tolerant to M. xenoplax, while the rootstocks Paulsen 1103 and Gravesac were susceptible and tolerant to the nematode. Mesocriconema xenoplax affected shoot and root fresh mass, altering photosynthetic pigments and total carbohydrates in susceptible genotypes. The increase in the activities of FAL, CAT, SOD, POD, PPO, APX, SOD and GLU enzymes was associated with the resistance reaction and tolerance of the studied grapevine genotypes. The effect of the interaction between M. xenoplax and I. macrodidyma potentiated vascular damage in susceptible grapevine genotypes. The parasitism of M. xenoplax favored infection by I. macrodidyma in susceptible grapevine genotypes. Two species of the root lesion nematode, P. brachyurus and P. zeae, were associated with declining vineyards in Santa Catarina state. Rootstocks immune to P. brachyurus (1111-21, 548-44, IBCA-125 and VR 043-43) were identified, while other genotypes (Paulsen 1103, Gravesac, IAC 313 Tropical, Salt Creek, Chardonnay and Bordô) were susceptible to that species. Pratylenchus brachyurus reduced the fresh mass of shoot and root, altered the levels of photosynthetic pigments and the balance of total carbohydrates in susceptible genotypes. There was synergism in the interactions between P. brachyurus, I. macrodidyma and susceptible grapevine genotypes. The combined effect of P. brachyurus and I. macrodidyma potentiated vascular damage in susceptible grapevine genotypes, predisposing plants to GDD. The species M. morocciensis was reported for the first time in Brazil parasitizing peach tree plants.