Pathogenicity of Bipolaris sorokiniana isolates from wheat roots, leaves and grains in Mexico

Abstract

Pathogenicity of 27 Bipolaris sorokiniana isolates from roots, leaves and grains of spring wheat, collected at a site in Mexico, showed no clear differences between groups of isolates, based on lesion density after seedling inoculation of the susceptible cultivar Ciano T-79 under controlled conditions. Results were variable when tests were repeated over time or in experiments using a smaller number of isolates. The lesion number per leaf was significantly different depending on the isolate used for inoculation, irrespective of the plant part group. No difference was found between individual isolates when pathogenicity was assessed using a disease severity scale. No cultivar-isolate interaction was observed for lesion density when 12 isolates were tested on six cultivars, but there were some significant differences between cultivars and between isolates. Results obtained confirmed that infection by B. sorokiniana is highly variable, and very sensitive to environmental conditions. In this study no physiological specialization was observed. The fungus appeared as a continuum of isolates differing in aggressiveness. This work was conducted with isolates from a single site, and highlights the need to assess carefully the biological significance of any differences observed among B. sorokiniana isolates.

Pathogenicity of fungi associated with wheat and barley seedling emergence and fungicide efficacy of seed treatment

“…The results seem to be useful for practical control measurement, because the C. sativus pathogenicity can be limited for cereal growing in warm conditions Fernandez & Jefferson 2004) and can be used for prediction for seedling damage via seedling pathogenicity test (Mesterhazy 1984). The pathogenicity test highlighted the variation among C. sativus isolates and host interactions during kernel germination, which is in agreement with the results of Duveiller & Garcia (2000). The greatest pathogenicity of the tested species towards seedlings was achieved by F. culmorum and F. graminearum relative to uninoculated control seedlings.…”

“…B. sorokiniana is highly variable and very sensitive to environmental conditions, no physiological specialization was observed. The fungus appeared as a continuum of isolates differing in aggressiveness (Duveiller & Garcia 2000). Spot blotch, caused by C. sativus, is a common foliar disease of barley.…”

Biological control of leaf disease of barley with Bacillus strain

“…The infection process of B. sorokiniana, as well as other fungal pathogens, consists of several stages: attachment to the host, spore germination, reception of signals from the plant that is required for appressorium formation, and secretion of extracellular enzymes for further penetration of the plant surface. Infection by B. sorokiniana is known to be highly variable and very sensitive to environmental conditions (Duveiller, Garcia Altamirano, 2000). Conidia of Bipolaris may therefore be unable to germinate at 17°C and may not be subject to antagonistic bacteria before germination.…”

Morphological and Pathogenic Variability in Bipolaris sorokiniana Causing Spot Blotch in Wheat (Triticum aestivum, T. durum, T. dicoccum) in India

“…Duveiller andAltomirana (2000) reported that pathogenicity of 27 isolates of B. sorokiniana, obtained from roots, leaves and grains of spring wheat showed no clear difference between groups of isolates on the basis of lesion density. In present studies, the variation in number of lesions per leaf was observed in case of different isolates.…”