Pathogenicity of Pythium species to maize

Abstract

Pythium isolates from diseased and dead bait plants of maize and cress grown in compost or various soils (maize fields, parkland under deciduous trees, grassland) were characterised and tested for pathogenicity to maize (Zea mays L.). In pot tests performed under controlled conditions, pathogenicity of the isolates to maize was apparent by reduction of root and shoot growth, whereas damping-off of maize seedlings was less frequent. Contrarily, pea seedlings were killed by pathogenic Pythium isolates. Pythium isolates from diseased maize seedlings and pathogenic strains from other gramineous plants (P. phragmitis, P. aff.phragmitis, P. catenulatum) were not necessarily more virulent to maize compared to isolates originating from dicotyledonous plants (cress). The most virulent isolates originated from compost and caused a reduction of maize shoot growth of up to 60%. Phylogenetic analysis revealed that they were very closely related to P. ultimum var. ultimum and P. arrhenomanes, respectively. Isolates originating from maize fields, grassland and parkland under deciduous trees, a reference culture of P. arrhenomanes and strains of P. phragmitis, P. aff. phragmitis and P. catenulatum with known pathogenicity on reed were non-pathogenic on maize. Isolates from compost, and from maize fields generally had a higher temperature optimum for mycelial growth (30 °C) and a faster growth rate (1.5–2.0 mm h−1) compared to the isolates from parkland under deciduous trees and grassland soil (20–25 °C, ~1.0 mm h−1), respectively. This study indicates a potential impact of pathogenic Pythium on maize plants even in the absence of visible symptoms.

Selection of bacteria and fungi for control of soilborne seedling diseases of maize

“…G. ultimum (CC-3) and R. solani AG2-2 IIIB were cultivated on seeds of buckwheat (Schmidt et al 2020) and pearl barley, respectively. The substrates were filled into 1-l Erlenmeyer flasks at 100 g per flask.…”

“…In addition to Fusarium spp., Rhizoctonia solani and different species of Globisporangium (syn. Pythium) are important soilborne pathogens of maize (Buddemeyer et al 2004; Thomsen et al 2018;Schmidt et al 2020). Maize seed is typically treated with chemical fungicides in order to reduce the impact of these pathogens (Sharma et al 2015).…”

Pythium Survey Europe provides deep insights into the genetic and structural diversity of Pythium communities and their disease potential in Europe

“…In Europe, intense corn cultivation in recent years boosted the risk of diseases 11 , such as damping off 12 and root rot [13][14][15] . Several pathogenic Pythium species have been reported to affect the growth of corn seedlings at varying initial temperatures 16,17 . However, there is currently very limited information on the disease potential of Pythium spp.…”

Specific interaction of an RNA-binding protein with the 3′-UTR of its target mRNA is critical to oomycete sexual reproduction

“…One of the most destructive oomycete pathogens [6], Pythium ultimum, displays a wide host range and has been recorded on hundreds of plant species worldwide, causing dampingoff and root rot that lead to huge yield losses [7]. P. ultimum is homothallic, meaning that a single isolate can mate with itself to complete the sexual stage; however, outcrossing has also been reported [8].…”

“…One of the most destructive oomycete pathogens [ 6 ], Pythium ultimum , displays a wide host range and has been recorded on hundreds of plant species worldwide, causing damping-off and root rot that lead to huge yield losses [ 7 ]. P .…”