Cultivar Effects on the Interaction between Free-Living Plant-Parasitic Nematodes and the Fungal Pathogen Rhizoctonia solani in Potato

Abstract

Crop damage is associated with infection by plant pathogens but can also arise through abiotic factors. However, the plant pathogens are involved in biotic interactions with other plant pathogens, and these interactions may differ depending of the cultivar of the crop. Here, the interaction between the fungus Rhizoctonia solani (AG3) and free-living plant-parasitic nematodes was investigated in a pot experiment with different potato cultivars. No synergistic interaction between R. solani and plant-parasitic nematodes was found, instead there was an effect of treatment with lower tuber yield when nematodes occurred alone. There were differences among the cultivars regarding incidence of black scurf, dry weight of stems and tubers, and there was interactive effects between treatment and cultivar regarding dry weight of stolons and roots. Therefore, results concerning incidence and damage of R. solani and/or plant-parasitic nematodes found for one cultivar may not be applicable to other cultivars.Resumen El daño en el cultivo se asocia con infección por fitopatógenos, pero también puede surgir a través de factores abióticos. No obstante, los patógenos de plantas están involucrados en interacciones bióticas con otros patógenos, y estas interacciones pudieran diferir dependiendo de la variedad del cultivo. Aquí, se investigó la interacción entre el hongo Rhizoctonia solani (AG3) y nematodos fitoparásitos de vida libre en un experimento en macetas con diferentes variedades de papa. No se encontró una interacción sinergística entre R. solani y los nematodos fitoparásitos, en cambio, hubo un efecto de tratamiento con rendimiento más bajo de tubérculo cuando los nematodos estaban solos. Hubo diferencias entre variedades en relación a la incidencia de costra negra, peso seco de los tallos y los tubérculos, y hubo efectos interactivos entre tratamiento y variedad en relación al peso seco de los estolones y las raíces. De aquí que los resultados concernientes a la incidencia y daño de R. solani y/o nematodos fitoparásitos que se encontraron para una variedad pudieran no ser aplicables a otras.

Temporal Interactions between Root-Lesion Nematodes and the Fungus Rhizoctonia Solani Lead to Reduced Potato Yield

“…Therefore, the yield loss found in our experiments most likely depended on the observed reduction of root biomass in the presence of nematodes, regardless of the time of inoculation (Table 2, Figure 1, and Figure 2). In addition, in some treatments, there was an interaction effect of nematodes and fungus on the root biomass, and similar results were also observed in a previous study, where the potato cultivar Kuras was inoculated with a full nematode community dominated by root-lesion nematodes in combination with R. solani [12].…”

“…An isolate of R. solani, AG2-1, originating from Vara, Sweden, was kindly provided by Dr. S. Ahlström (Dept. of Forest Mycology and Plant Pathology SLU, Uppsala, Sweden), which was the same isolate as that used in the experiments previously published [12,21]. The methodology was also the same as in those experiments, that is, the fungal mycelium was mixed to small pieces and diluted in tap water to correspond to 0.01 g mycelium pot −1 within the same volume as for the inoculation of the nematodes.…”

“…The potato plants were harvested ten weeks after the first inoculation. This was performed as previously described [12,21]. In short, the potato plant was taken out of the pot; washed carefully with tap water; dried with a paper towel; and divided into stems, roots, stolons, and tubers.…”

“…increased in co-occurrence with P. penetrans and R. solani. A previous study revealed that a full nematode community, dominated by the root-lesion nematode Pratylenchus crenatus (Loof, 1960), had a negative impact on tuber yield in a pot experiment [12]. Other nematode species interacting with R. solani are the potato cyst nematodes Globodera rostochiensis (Wollenweber, 1923) [13,14] and Globodera pallida (Stone, 1973), 1975 [15,16], which can result in large yield losses.…”

Root‐lesion nematodes of potato: Current status of diagnostics, pathogenicity and management

“…(Back et al, 2002(Back et al, , 2010, but it is still unclear if a synergistic interaction with Pratylenchus spp. on potatoes occurs (Kotcon et al, 1985;Kenyon and Smith, 2007;Björsell et al, 2017;Viketoft et al, 2017).…”