This page has only limited features, please log in for full access.
Toxins have been proposed to facilitate fungal root infection by creating regions of readily-penetrated necrotic tissue when applied externally to intact roots. Isolates of the charcoal rot disease fungus, Macrophomina phaseolina, from soybean plants in Mississippi produced a phytotoxic toxin, (−)-botryodiplodin, but no detectable phaseolinone, a toxin previously proposed to play a role in the root infection mechanism. This study was undertaken to determine if (−)-botryodiplodin induces toxic responses of the types that could facilitate root infection. (±)-Botryodiplodin prepared by chemical synthesis caused phytotoxic effects identical to those observed with (−)-botryodiplodin preparations from M. phaseolina culture filtrates, consistent with fungus-induced phytotoxicity being due to (−)-botryodiplodin, not phaseolinone or other unknown impurities. Soybean leaf disc cultures of Saline cultivar were more susceptible to (±)-botryodiplodin phytotoxicity than were cultures of two charcoal rot-resistant genotypes, DS97-84-1 and DT97-4290. (±)-Botryodiplodin caused similar phytotoxicity in actively growing duckweed (Lemna pausicostata) plantlet cultures, but at much lower concentrations. In soybean seedlings growing in hydroponic culture, (±)-botryodiplodin added to culture medium inhibited lateral and tap root growth, and caused loss of root caps and normal root tip cellular structure. Thus, botryodiplodin applied externally to undisturbed soybean roots induced phytotoxic responses of types expected to facilitate fungal root infection.
Hamed K. Abbas; Nacer Bellaloui; Alemah M. Butler; Justin L. Nelson; Mohamed Abou-Karam; W. Thomas Shier. Phytotoxic Responses of Soybean (Glycine max L.) to Botryodiplodin, a Toxin Produced by the Charcoal Rot Disease Fungus, Macrophomina phaseolina. Toxins 2020, 12, 25 .
AMA StyleHamed K. Abbas, Nacer Bellaloui, Alemah M. Butler, Justin L. Nelson, Mohamed Abou-Karam, W. Thomas Shier. Phytotoxic Responses of Soybean (Glycine max L.) to Botryodiplodin, a Toxin Produced by the Charcoal Rot Disease Fungus, Macrophomina phaseolina. Toxins. 2020; 12 (1):25.
Chicago/Turabian StyleHamed K. Abbas; Nacer Bellaloui; Alemah M. Butler; Justin L. Nelson; Mohamed Abou-Karam; W. Thomas Shier. 2020. "Phytotoxic Responses of Soybean (Glycine max L.) to Botryodiplodin, a Toxin Produced by the Charcoal Rot Disease Fungus, Macrophomina phaseolina." Toxins 12, no. 1: 25.
Charcoal rot disease, caused by the fungus Macrophomina phaseolina, results in major economic losses in soybean production in southern USA. M. phaseolina has been proposed to use the toxin (-)-botryodiplodin in its root infection mechanism to create a necrotic zone in root tissue through which fungal hyphae can readily enter the plant. The majority (51.4%) of M. phaseolina isolates from plants with charcoal rot disease produced a wide range of (-)-botryodiplodin concentrations in a culture medium (0.14–6.11 µg/mL), 37.8% produced traces below the limit of quantification (0.01 µg/mL), and 10.8% produced no detectable (-)-botryodiplodin. Some culture media with traces or no (-)-botryodiplodin were nevertheless strongly phytotoxic in soybean leaf disc cultures, consistent with the production of another unidentified toxin(s). Widely ranging (-)-botryodiplodin levels (traces to 3.14 µg/g) were also observed in the roots, but not in the aerial parts, of soybean plants naturally infected with charcoal rot disease. This is the first report of (-)-botryodiplodin in plant tissues naturally infected with charcoal rot disease. No phaseolinone was detected in M. phaseolina culture media or naturally infected soybean tissues. These results are consistent with (-)-botryodiplodin playing a role in the pathology of some, but not all, M. phaseolina isolates from soybeans with charcoal rot disease in southern USA.
Hamed K. Abbas; Nacer Bellaloui; Cesare Accinelli; James R. Smith; W. Thomas Shier; Alemah Butler. Toxin Production in Soybean (Glycine max L.) Plants with Charcoal Rot Disease and by Macrophomina phaseolina, the Fungus that Causes the Disease. Toxins 2019, 11, 645 .
AMA StyleHamed K. Abbas, Nacer Bellaloui, Cesare Accinelli, James R. Smith, W. Thomas Shier, Alemah Butler. Toxin Production in Soybean (Glycine max L.) Plants with Charcoal Rot Disease and by Macrophomina phaseolina, the Fungus that Causes the Disease. Toxins. 2019; 11 (11):645.
Chicago/Turabian StyleHamed K. Abbas; Nacer Bellaloui; Cesare Accinelli; James R. Smith; W. Thomas Shier; Alemah Butler. 2019. "Toxin Production in Soybean (Glycine max L.) Plants with Charcoal Rot Disease and by Macrophomina phaseolina, the Fungus that Causes the Disease." Toxins 11, no. 11: 645.
Hamed K. Abbas; W. Thomas Shier; Javier Plasencia; Mark A. Weaver; Nacer Bellaloui; Jeremy K. Kotowicz; Alemah M. Butler; Cesare Accinelli; M. Eugenia de la Torre-Hernandez; Robert M. Zablotowicz. Mycotoxin contamination in corn smut (Ustilago maydis) galls in the field and in the commercial food products. Food Control 2017, 71, 57 -63.
AMA StyleHamed K. Abbas, W. Thomas Shier, Javier Plasencia, Mark A. Weaver, Nacer Bellaloui, Jeremy K. Kotowicz, Alemah M. Butler, Cesare Accinelli, M. Eugenia de la Torre-Hernandez, Robert M. Zablotowicz. Mycotoxin contamination in corn smut (Ustilago maydis) galls in the field and in the commercial food products. Food Control. 2017; 71 ():57-63.
Chicago/Turabian StyleHamed K. Abbas; W. Thomas Shier; Javier Plasencia; Mark A. Weaver; Nacer Bellaloui; Jeremy K. Kotowicz; Alemah M. Butler; Cesare Accinelli; M. Eugenia de la Torre-Hernandez; Robert M. Zablotowicz. 2017. "Mycotoxin contamination in corn smut (Ustilago maydis) galls in the field and in the commercial food products." Food Control 71, no. : 57-63.