Tropical Plant Pathology
URI permanente para esta coleçãohttps://thoth.dti.ufv.br/handle/123456789/13106
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Item Volatile organic compounds for the control of Meloidogyne exigua in Coffea arabica(Sociedade Brasileira de Fitopatologia, 2013) Silva, Willian R. J.; Machado, Alan R. T.; Campos, Viviane A. C.; Zeri, Ana C. M.; Campos, Vicente P.; Oliveira, Denilson F.Meloidogyne exigua is a plant-parasitic nematode that causes great losses to coffee farmers. Thus, to contribute to the development of new products to control this parasite, the present work studied the effect of volatile organic compounds (VOC) on the nematode and coffee plants (Coffea arabica), since these compounds are known to be used in plant defense against other agronomical pests. The number of galls of M. exigua was reduced when the aerial part of coffee plants was sprayed with combinations of methyl jasmonate + jasmone, (Z)-hex-3-en-1-ol + (E)-hex-3-en-1-ol + (Z)-hex-2-en-1-ol + (E)-hex-2-enal, (E)-hex-2-enyl acetate + hexyl acetate, meso-butane-2,3-diol + butane-1,2-diol + butane-1,3-diol + butane-1,4-diol, 3-hydroxybutan-2-one + 4-hydroxybutan-2-one or linalyl acetate + nerolidol. These VOC also caused alterations in the concentrations of substances such as alkaloids, phenols, amino acids and carbohydrates, in the roots of coffee plants. The findings suggest that these VOC may be explored as potential products for the control of M. exigua in coffee plants.Item Defense responses to Meloidogyne exigua in resistant coffee cultivar and non-host plant(Sociedade Brasileira de Fitopatologia, 2013) Silva, Rodrigo V.; Oliveira, Rosângela D.L.; Ferreira, Patrícia S.; Ferreira, Aline O.; Rodrigues, Fabrício A.The resistance of coffee plants to Meloidogyne exigua is conferred by the gene Mex-1. However, the mechanisms of resistance still need to be clarified. Therefore, the penetration, development and reproduction of two populations of M. exigua (M1, isolated from the coffee plant and M2, from rubber tree) in susceptible (Coffea arabica ‘Catuai’) and resistant (C. canephora ‘Apoatã’) cultivars were studied. A greater quantity of J2 from M1 penetrated the susceptible cultivar, but there was no difference between the cultivars for M2. Although the resistant coffee cultivar formed some galls, the nematode did not reproduce. M2 did not induce the formation of galls or the production of eggs in either cultivars. Events related to hypersensitive reaction (HR) were observed as well as other defense responses of the coffee cultivar against M. exigua, which inhibited the formation of the feeding site, provoked emigration of the J2 and delayed or inhibited development and reproduction. The response of the non-host plant was more effective, because it did not allow development of the nematode or, consequently, its reproduction. It was concluded that the coffee cultivar’s resistance to M. exigua is not restricted to HR, but rather to a set of defense responses, both constitutive and induced, expressed after nematode penetration, especially phenolic-like compounds.