Control of Pratylenchus brachyurus in soybean with Trichoderma spp. and resistance inducers

Abstract

Trichoderma spp. is a fungus with nematode control potential; however, its potential to control the root lesion nematode Pratylenchus brachyurus remains poorly studied.Thus, the aim of this study was to select Trichoderma spp. isolates and assess their ability to control P. brachyurus in soybean crops. Different experiments were conducted aiming at selecting isolates, assessing whether they were able to reduce nematode penetration in plants or cause mortality in vitro, and whether they were able to induce resistance in soybean, as well as at studying the possibility of using the selected isolates associated with resistance inducers (acibenzolar-S-methyl, Ecolife™ and AgroMos™). The selection experiment found three isolates showing satisfactory results, namely GF422, GF425 and GF427; the GF362 isolate was assessed in the subsequent experiments. These four isolates reduced P. brachyurus penetration in soybean roots and promoted nematode mortality in vitro. Increased total protein and catalase activity were recorded, mainly in the 72-hr assessments. Overall, the protein production was different between isolates. The best results were found in the combination between the GF362 isolate and the three resistance inducers, between GF427 and Ecolife™, between GF427 and AgroMos™ and between GF422 and Ecolife™. K E Y W O R D Sbiological control, Glycine max, nematophagous fungi, resistance induction, root lesion nematode

Biological control of Pratylenchus brachyurus in soya bean crops

“…The Trichoderma isolate used in the present study is not registered for nematode control purposes, although it is registered for the control of soil fungi. However, it showed positive results in terms of P. brachyurus reduction, as observed in the greenhouse and field experiments conducted in Londrina County, thus corroborating previous studies conducted with other species and isolates of the same fungus (Gonçalves Júnior et al., ; Kath et al., ). It is worth highlighting that Trichoderma isolates differ from each other in their efficiency in controlling P. brachyurus and other nematodes (Affokpon et al., ; Kath et al., ; Sharon et al., ).…”

“…However, it showed positive results in terms of P. brachyurus reduction, as observed in the greenhouse and field experiments conducted in Londrina County, thus corroborating previous studies conducted with other species and isolates of the same fungus (Gonçalves Júnior et al., ; Kath et al., ). It is worth highlighting that Trichoderma isolates differ from each other in their efficiency in controlling P. brachyurus and other nematodes (Affokpon et al., ; Kath et al., ; Sharon et al., ). However, different isolates may act in different ways, such as through the direct parasitism of eggs and juveniles due to the production of enzymes such as chitinases, lipases and proteases; through changes in root exudates found in the rhizosphere region, which may reduce juvenile hatching and compromise the host recognition process by changing the stimuli around the root; and through the production of substances capable of activating plant defence mechanisms (Harman, ; Kath et al., ; Sahebani & Hadavi, ; Sharon, Bar‐Eyal, Chet, Herrera‐Estrella, & Spiegel, ).…”

“…It is worth highlighting that Trichoderma isolates differ from each other in their efficiency in controlling P. brachyurus and other nematodes (Affokpon et al., ; Kath et al., ; Sharon et al., ). However, different isolates may act in different ways, such as through the direct parasitism of eggs and juveniles due to the production of enzymes such as chitinases, lipases and proteases; through changes in root exudates found in the rhizosphere region, which may reduce juvenile hatching and compromise the host recognition process by changing the stimuli around the root; and through the production of substances capable of activating plant defence mechanisms (Harman, ; Kath et al., ; Sahebani & Hadavi, ; Sharon, Bar‐Eyal, Chet, Herrera‐Estrella, & Spiegel, ). Recently, isolates selected as promising for P. brachyurus control increased the mortality of infective forms, reduced nematode penetration and reproduction in soya bean plants, and increased the total protein and catalase in host plants (Kath et al., ).…”

“…On the other hand, some Trichoderma spp. isolates show the potential to control this nematode (Gonçalves Júnior, Roldi, Namur, & Machado, ; Kath et al., ); however, commercial products with registration for soil fungi control purposes have not yet been evaluated for P. brachyurus .…”

Biological nematicides associated with biofertilizers in the management of Pratylenchus zeae in sugarcane

“…These fungi and bacteria show high potential in reducing nematodes in many pathosystems (Affokpon et al, 2011;Cardoso & Araújo, 2011;Freitas et al, 2012;Xiang et al, 2017). Both present multiple action forms; Trichoderma spp., for instance, can produce toxic compounds (Sharon et al, 2001) and enzymes linked to phytonematode parasitism (Zhang et al, 2015), causing changes in root exudates and inducing plant-defense mechanisms (Kath et al, 2017). Bacillus spp.…”