A note on phytotoxicity of homodestruxin B – a compound produced by Alternaria brassicae

Abstract

Homodestruxin B, a compound produced by Alternaria brassicae, the causal organism of the blackspot disease of rapeseed, is known to be phytotoxic to the leaves of Brassica napus. In this study we found that its phytotoxicity was comparable to that of destruxin B, another toxin produced by the pathogen when tested on B. napus. Homodestruxin B caused symptoms of different severities in leaves of various non-host plants. The results suggestthat homodestruxin B is a non-host-specific toxin.

Alternaria blight of oilseed Brassicas: A comprehensive review

“…Parada et al (2007) studied the host specificity of destruxin B and indicated its non-host specific nature supporting the result of Buchwaldt and Green (1992). Bains et al (1993) worked on the host specificity of homodestruxin B and observed the symptom of different severities in leaves of various non-host plants and suggested that homodestruxin B is non-host specific toxin. Host selective toxins are toxic only to the host plant, and have an important role in pathogenesis as primary determinants of virulence or pathogenicity.…”

Alternaria blight of oilseed Brassicas: A comprehensive review

“…Parada et al (2007) studied the host specificity of destruxin B and indicated its non-host specific nature supporting the result of Buchwaldt and Green (1992). Bains et al (1993) worked on the host specificity of homodestruxin B and observed the symptom of different severities in leaves of various non-host plants and suggested that homodestruxin B is non-host specific toxin. Host selective toxins are toxic only to the host plant, and have an important role in pathogenesis as primary determinants of virulence or pathogenicity.…”

Epidemiology, Genetics and Resistance of Alternaria Blight in Oilseed Brassica

“…In a non-host plant, the dietary deficiency and the presence of antimicrobial compounds in the apoplast can also prevent the production of hyphae into mycelium [71]. The pathogen also generates non-host specific or general toxins that might damage plant cells, leading ultimately to necrosis [78][79][80]. To avoid this, a non-host plant may recognize these toxins and employ defense mechanisms to detoxify these toxins [81].…”

Perspectives on the utilization of resistance mechanisms from host and nonhost plants for durable protection ofBrassicacrops against Alternaria blight

“…For example, A. brassicae fails to penetrate the cell wall in tomato and wheat plants, and callose-containing papilla formation is observed in the cell wall regions where the pathogen attempts to penetrate such plants(McRoberts & Lennard, 1996). The pathogen also produces nonhost-specific or general toxins that can damage the plant cells, which eventually leads to necrosis (Buchwaldt & Green, 1992; Bains, Tewari & Ayer, 1993; Parada et al, 2007). To avoid this, a nonhost plant may recognize these toxins and employ defense mechanisms to detoxify these toxins (Pedras et al, 2001).…”

Alternaria blight of oilseed Brassicas: A comprehensive review

“…Parada et al (2007) studied the host specificity of destruxin B and indicated its non-host specific nature supporting the result of Buchwaldt and Green (1992). Bains et al (1993) worked on the host specificity of homodestruxin B and observed the symptom of different severities in leaves of various non-host plants and suggested that homodestruxin B is non-host specific toxin. Host selective toxins are toxic only to the host plant, and have an important role in pathogenesis as primary determinants of virulence or pathogenicity.…”

Epidemiology, Genetics and Resistance of Alternaria Blight in Oilseed Brassica

“…In a non-host plant, the dietary deficiency and the presence of antimicrobial compounds in the apoplast can also prevent the production of hyphae into mycelium [71]. The pathogen also generates non-host specific or general toxins that might damage plant cells, leading ultimately to necrosis [78][79][80]. To avoid this, a non-host plant may recognize these toxins and employ defense mechanisms to detoxify these toxins [81].…”

Perspectives on the utilization of resistance mechanisms from host and nonhost plants for durable protection ofBrassicacrops against Alternaria blight

“…For example, A. brassicae fails to penetrate the cell wall in tomato and wheat plants, and callose-containing papilla formation is observed in the cell wall regions where the pathogen attempts to penetrate such plants(McRoberts & Lennard, 1996). The pathogen also produces nonhost-specific or general toxins that can damage the plant cells, which eventually leads to necrosis (Buchwaldt & Green, 1992; Bains, Tewari & Ayer, 1993; Parada et al, 2007). To avoid this, a nonhost plant may recognize these toxins and employ defense mechanisms to detoxify these toxins (Pedras et al, 2001).…”

Alternaria blight of oilseed Brassicas: A comprehensive review

“…Parada et al (2007) studied the host specificity of destruxin B and indicated its non-host specific nature supporting the result of Buchwaldt and Green (1992). Bains et al (1993) worked on the host specificity of homodestruxin B and observed the symptom of different severities in leaves of various non-host plants and suggested that homodestruxin B is non-host specific toxin. Host selective toxins are toxic only to the host plant, and have an important role in pathogenesis as primary determinants of virulence or pathogenicity.…”

Epidemiology, Genetics and Resistance of Alternaria Blight in Oilseed Brassica

“…In a non-host plant, the dietary deficiency and the presence of antimicrobial compounds in the apoplast can also prevent the production of hyphae into mycelium [71]. The pathogen also generates non-host specific or general toxins that might damage plant cells, leading ultimately to necrosis [78][79][80]. To avoid this, a non-host plant may recognize these toxins and employ defense mechanisms to detoxify these toxins [81].…”

Perspectives on the utilization of resistance mechanisms from host and nonhost plants for durable protection ofBrassicacrops against Alternaria blight

“…For example, A. brassicae fails to penetrate the cell wall in tomato and wheat plants, and callose-containing papilla formation is observed in the cell wall regions where the pathogen attempts to penetrate such plants(McRoberts & Lennard, 1996). The pathogen also produces nonhost-specific or general toxins that can damage the plant cells, which eventually leads to necrosis (Buchwaldt & Green, 1992; Bains, Tewari & Ayer, 1993; Parada et al, 2007). To avoid this, a nonhost plant may recognize these toxins and employ defense mechanisms to detoxify these toxins (Pedras et al, 2001).…”