Micorrização e indução de quitinases e β-1,3-glucanases e resistência à fusariose em porta-enxerto de videira

Abstract

Resumo -O objetivo deste trabalho foi avaliar os níveis de expressão de β-1,3-glucanases e quitinases nos porta-enxertos de videira SO4 e R110, respectivamente suscetível e resistente a Fusarium oxysporum f. sp. herbemontis, bem como avaliar o efeito do fungo micorrízico arbuscular Glomus intraradices no crescimento, na expressão dessas enzimas e na supressão do patógeno no porta-enxerto suscetível. Foram quantificadas as atividades enzimáticas de β-1,3-glucanases e quitinases nas raízes dos porta-enxertos. Mudas do portaenxerto SO4 receberam inóculos de G. intraradices e F. oxysporum, e foram avaliadas quanto ao crescimento, atividade das duas enzimas e sintomas de doença. As atividades das enzimas nas raízes do porta-enxerto resistente aumentaram entre 0 e 5 dias após a inoculação do patógeno. A atividade de quitinases nas raízes do porta-enxerto suscetível aumentou com a inoculação do fungo micorrízico e do patógeno. A atividade de β-1,3-glucanases foi maior somente com a presença do fungo micorrízico e do patógeno. Videiras com inoculação de G. intraradices apresentaram diminuição nos sintomas de infecção por Fusarium spp., o que indica que o fungo micorrízico promove a indução de quitinases e β-1,3-glucanases especificamente na supressão ou inibição do patógeno.Termos para indexação: Fusarium oxysporum, Glomus, Vitis. Mycorrhizal inoculation and induction of chitinases and β-1,3-glucanases and fusarium resistance in grapevine rootstockAbstract -The objective of this work was to evaluate the expression levels of β-1,3-glucanases and chitinases in SO4 and 110 grapevine rootstocks, respectively susceptible and resistant to Fusarium oxysporum f. sp. herbemontis, as well as to evaluate the effect of the arbuscular mycorrhizal fungus Glomus intraradices on plant growth, on enzyme expression and on pathogen suppression in the susceptible rootstock. The enzyme activities of β-1,3-glucanases and chitinases in the rootstocks roots were evaluated. Plant growth, enzyme activity, and disease symptoms were evaluated in SO4 plantlets inoculated with G. intraradices and F. oxysporum. Enzyme activities in the plant roots increased in the resistant rootstock, between 0 and 5 days after pathogen inoculation. In the susceptible rootstock, chitinase activity enhanced after the mycorrhizal fungus and the pathogen inoculations. β-1,3-glucanase activity increased only in the presence of both the mycorrhizal and the pathogenic fungi. G. intraradices-inoculated SO4 grapevine plantlets showed decreased symptoms of Fusarium infection, which indicates that the mycorrhizal fungus promotes chitinase and β-1,3-glucanase activities leading to pathogen suppression or inhibition.

Root Proteomic Analysis of Grapevine Rootstocks Inoculated with Rhizophagus irregularis and Fusarium oxysporum f. sp. herbemontis

“…It has been shown that mycorrhizal plants may have fewer and shorter roots than non-mycorrhizal plants, since extraradicular AMF mycelium increases the volume of soil explored by the plant root system, allowing higher water and nutrient uptake (Locatelli et al, 2002). Therefore, these results confirm the ability of AMF to benefit plant growth, and the increase in shoot and root biomass is consistent with previous studies with grapevine rootstocks (Dalla Costa et al, 2010;Anzanello et al, 2011;Cangahuala-Inocente et al, 2011) or with other plant species (Lovato et al, 2006;Farzaneh et al, 2011;Cavagnaro et al, 2012;Evelin et al, 2012;Mohandas, 2012;Steinkellner et al, 2012). Anzanello et al (2011) detected an increase in shoot and root biomass in SO4 and P1103 rootstocks inoculated with AMF, and Dalla Costa et al (2010) also showed an increase in shoot biomass in SO4 rootstock inoculated with AMF.…”

“…That suggests a bioprotective effect of AMF against FOH colonization in both grapevine rootstocks, which is more marked in the susceptible SO4 rootstock. Dalla Costa et al (2010) also detected a decrease in disease symptoms in SO4 grapevine rootstocks co-inoculated with AMF and FOH. In two independent studies, Steinkellner et al (2012) and Fierro-Coronado et al (2013) showed (Schenkluhn et al, 2010), which occur when either mutualistic or pathogenic microorganisms are inoculated.…”

“…SO4 and R110 rootstocks, from the plant collection of the Federal University of Santa Catarina, were micropropagated in vitro in DSD1culture medium (Lima da Silva and Doazan, 1995) Costa et al, 2010). Prior to transplant, all plants were trimmed to have 1.0-cm roots, 2.5 to 3.0 cm height and 3 to 4 leaves.…”

“…Among the grapevine rootstocks available in southern Brazil, the SO4 rootstock (Vitis berlandieri × V. riparia) was commonly used in grapevine production due to its adaptability to different types of soils and climate, as well as to its vigour, which ensures high yield and fruit quality. However, SO4 was replaced, due to its susceptibility to FOH (Andrade et al, 1993;Dalla Costa et al, 2010;Cangahuala-Inocente et al, 2011), by Paulsen 1103, R99 and R110 (V. berlandieri × V. rupestris), and VR043-43 (V. vinifera × V. rotundifolia) grapevine rootstocks, resistant to FOH, which are currently the most recommended rootstocks in southern Brazil (Sônego et al, 2005;Souza et al, 2013). These rootstocks have low root development, and consequently low yield, but they have a long production cycle (Dalla Costa et al, 2010).…”

“…For this reason, AMF are known as a biological control tool for use in agriculture (Gianinazzi et al, 2010;Trouvelot et al, 2015). Many studies have shown that AMF improve plant resistance to soil pathogenic fungi, including Fusarium in grapevine rootstocks and tomato plants (Dalla Costa et al, 2010;Fierro-Coronado et al, 2013), and also act against nematodes in grapevine rootstocks (Hao et al, 2012). Inoculation of grapevine rootstocks with AMF is therefore an option to reduce or neutralize damage from soil-borne diseases.…”