Interaction of spatially separated Pratylenchus penetrans and Verticillium dahliae on potato measured by impaired photosynthesis

Abstract

Experiments were conducted under growth-chamber conditions to determine if Pratylenchus penetrans systemically alters light use efficiency (LUE) of Russet Burbank potato infected by Verticillium dahliae. Pathogen separation was achieved by inoculating potato roots with the nematode prior to injecting fungal conidia into the stem vasculature. Treatments were P. penetrans alone, V. dahliae alone, nematode and fungus together, and a no-pathogen control. Gas exchange was repeatedly and nondestructively measured on the fifth-youngest leaf with a Li-Cor LI-6200 portable photosynthesis system. By 16 and 20 days after stem injection with the fungus, LUE was synergistically impaired in jointly infected plants. Transpiration in plants infected with both pathogens was significantly reduced. However, the combined effect of nematode and fungus was synergistic in one experiment and additive in the other. Stems were destructively harvested when LUE was synergistically impaired. Coinfected potato plants contained more colony-forming units (CFU) of V. dahliae in stem sap than those infected by the fungus alone in one experiment. Evidence is provided that infection of Russet Burbank roots by P. penetrans systemically affects disease physiology associated with stem vascular infection by V. dahliae. The findings indicate that the role of the nematode in the fungus/ host interaction is more than simply to facilitate extravascular and /or vascular entry of the fungus into potato roots.

Cross-pathogenicity of Verticillium dahliae between potato and sunflower

“…Sornetimes the fungus interacts with the root lesion nematode PratylenchLts peneÍrans and the root rot bacteria Erwinia coccodes to cause a complex vascular wilt disease known as potato eally dying (Rotenberg et al, 2004;Rowe and Powelson, 2002 Xiao et al, 1997), and fruits such as strawbemy and olive (Levin et al, 2003;Harris and Yong, 1996) (Hastie and Heale, 1984 (Typas, 1983;Typas and Heale, 1978 This ability is termed vegetative compatibility (Puhalla,1979 (Rowe and Powelson.2002). The microsclerotia of V. dahliae survive in the soil more than ten years and it can germinate in response to root exudates secreted fi'orn the root tip (Mol, 1995).…”

Development of a potato seedling assay to screen for resistance to Verticillium dahliae

“…Another area of future research should include the role of Vd toxin in the interaction with the root lesion nematode P. penetrans. Symptom expression and colonization by Vd is enhanced during coinfection with this nematode (Martin et al 1982, MacGuidwin and Rouse 1990, Rotenberg et al 2004. Many questions related to the role of P. penetrans in eliciting increased susceptibility to Vd or increased sensitivity to Vd phytotoxins remain to be answered.…”

“…1982, Riedel and Rowe 1985, Rowe et al. 1985, 1987, MacGuidwin and Rouse 1990, Rotenberg et al. 2004).…”

“…VW is mainly caused by the soil-borne fungus Verticillium dahliae Kleb. (Vd), but symptom expression and colonization by Vd is enhanced during coinfection with the root lesion nematode Pratylenchus penetrans (Martin et al 1982, 1987, MacGuidwin and Rouse 1990, Rotenberg et al 2004. Host resistance is regarded as the most promising method of managing VW (Rowe and Powelson 2002).…”

Expression of a cystatin transgene can confer resistance to root lesion nematodes in Lilium longiflorum cv. ‘Nellie White’

“…are migratory endoparasitic nematodes that feed and migrate within the root cortical tissue causing a reduction in root growth after infection, accompanied by the formation of lesions, necrotic areas, browning and cell death (Jones and Fosu-Nyarko 2014), often followed by root rotting from secondary attack by soil fungi (Rotenberg et al 2004) or bacteria (Vrain and Copeman 1987). Pratylenchus penetrans (Cobb, 1917) Filipjev andSchuurmans Stekhoven, 1941 infestations are particularly important in the production of Easter lilies (Lilium longiflorum Thunb.…”