Effects of Nitrogen, Plant Density, Moisture Stress and Artificial Inoculation with Macrophomina phaseolina on Charcoal Rot Incidence in Grain Sorghum

Laboratory and greenhouse studies examined effects of atrazine, alachlor, and metolachlor on growth and colonization of grain sorghum roots byMacrophomina phaseolina, causal fungus for charcoal rot disease. In laboratory studies, all three herbicides reduced fungal colony diameter and increased production of microsclerotia. Alachlor and metolachlor reduced germination of fungal microsclerotia. Atrazine did not affect microsclerotia germination, but lessened the effects of alachlor and metolachlor on germination when applied in combination. In greenhouse studies, atrazine reduced numbers ofM. phaseolinamicrosclerotia recovered from soil after 8 wk, and this resulted in reduced colonization of roots by this fungus at harvest. Colonization of grain sorghum roots byM. phaseolinawas not affected by alachlor or metolachlor. Grain sorghum growth was reduced by atrazine at all intervals and by alachlor and metolachlor at harvest, despite use of seed safened with cyometrinil.

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The Necrotrophic Fungus Macrophomina phaseolina Promotes Charcoal Rot Susceptibility in Grain Sorghum Through Induced Host Cell-Wall-Degrading Enzymes

Phytopathology ◽

10.1094/phyto-12-17-0404-r ◽

2018 ◽

Vol 108 (8) ◽

pp. 948-956 ◽

Cited By ~ 7

Author(s):

Y. M. A. Y. Bandara ◽

D. K. Weerasooriya ◽

S. Liu ◽

C. R. Little

Keyword(s):

Cell Wall ◽

Glycosyl Hydrolase ◽

Pectin Methylesterase ◽

Macrophomina Phaseolina ◽

Grain Sorghum ◽

Cell Wall Degrading Enzymes ◽

Charcoal Rot ◽

Degrading Enzymes ◽

Encoding Genes ◽

Polygalacturonase Activity

The cell-wall-degrading enzymes (CWDE) secreted by necrotrophs are important virulence factors. Although not unequivocally demonstrated, it has been suggested that necrotrophs induce hosts to cooperate in disease development through manipulation of host CWDE. The necrotrophic fungus Macrophomina phaseolina causes charcoal rot disease in Sorghum bicolor. An RNA-seq experiment was conducted to investigate the behavior of sorghum CWDE-encoding genes after M. phaseolina inoculation. Results revealed M. phaseolina’s ability to significantly upregulate pectin methylesterase-, polygalacturonase-, cellulase-, endoglucanase-, and glycosyl hydrolase-encoding genes in a charcoal rot-susceptible sorghum genotype (Tx7000) but not in a resistant genotype (SC599). For functional validation, crude enzyme mixtures were extracted from M. phaseolina- and mock-inoculated charcoal-rot-resistant (SC599 and SC35) and -susceptible (Tx7000 and BTx3042) sorghum genotype stalks. A gel diffusion assay (pectin substrate) revealed significantly increased pectin methylesterase activity in M. phaseolina-inoculated Tx7000 and BTx3042. Polygalacturonase activity was determined using a ruthenium red absorbance assay (535 nm). Significantly increased polygalacturonase activity was observed in two susceptible genotypes after M. phaseolina inoculation. The activity of cellulose-degrading enzymes was determined using a 2-cyanoacetamide fluorimetric assay (excitation and emission maxima at 331 and 383 nm, respectively). The assay revealed significantly increased cellulose-degrading enzyme activity in M. phaseolina-inoculated Tx7000 and BTx3042. These findings revealed M. phaseolina’s ability to promote charcoal rot susceptibility in grain sorghum through induced host CWDE.

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Toxin Production in Soybean (Glycine max L.) Plants with Charcoal Rot Disease and by Macrophomina phaseolina, the Fungus that Causes the Disease

Toxins ◽

10.3390/toxins11110645 ◽

2019 ◽

Vol 11 (11) ◽

pp. 645 ◽

Cited By ~ 8

Author(s):

Hamed K. Abbas ◽

Nacer Bellaloui ◽

Cesare Accinelli ◽

James R. Smith ◽

W. Thomas Shier

Keyword(s):

Culture Media ◽

Leaf Disc ◽

Toxin Production ◽

Macrophomina Phaseolina ◽

Economic Losses ◽

Limit Of Quantification ◽

Charcoal Rot ◽

Wide Range ◽

Soybean Plants ◽

Rot Disease

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.

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Phaseocyclopentenones A and B, Phytotoxic Penta- and Tetrasubstituted Cyclopentenones Produced by Macrophomina phaseolina, the Causal Agent of Charcoal Rot of Soybean in Argentina

Journal of Natural Products ◽

10.1021/acs.jnatprod.0c01287 ◽

2021 ◽

Vol 84 (2) ◽

pp. 459-465

Author(s):

Marco Masi ◽

Francisco Sautua ◽

Roukia Zatout ◽

Stefany Castaldi ◽

Lorenzo Arrico ◽

...

Keyword(s):

Macrophomina Phaseolina ◽

Causal Agent ◽

Charcoal Rot

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Progress of soybean charcoal rot under tillage and no-tillage systems in Brazil

Fitopatologia Brasileira ◽

10.1590/s0100-41582003000200002 ◽

2003 ◽

Vol 28 (2) ◽

pp. 131-135 ◽

Cited By ~ 13

Author(s):

Álvaro M. R. Almeida ◽

Lilian Amorim ◽

Armando Bergamin Filho ◽

Eleno Torres ◽

José R. B. Farias ◽

...

Keyword(s):

Cropping Systems ◽

Disease Incidence ◽

Cropping System ◽

Macrophomina Phaseolina ◽

Conventional System ◽

Survival Times ◽

Charcoal Rot ◽

No Till ◽

Four Seasons ◽

Conventional Systems

The increase in incidence of charcoal rot caused by Macrophomina phaseolina on soybeans (Glycine max) was followed four seasons in conventional and no-till cropping systems. In the 1997/98 and 2000/01 seasons, total precipitation between sowing and harvest reached 876.3 and 846.9 mm, respectively. For these seasons, disease incidence did not differ significantly between the no-till and conventional systems. In 1998/99 and 1999/00 precipitation totaled 689.9 and 478.3 mm, respectively. In 1998/99, in the no-till system, the disease incidence was 43.7% and 53.1% in the conventional system. In 1999/00 the final incidence was 68.7% and 81.2% for the no-till and conventional systems, respectively. For these two seasons, precipitation was lower than that required for soybean crops (840 mm), and the averages of disease incidence were significantly higher in the conventional system. The concentration of microsclerotia in soil samples was higher in samples collected in conventional system at 0 - 10 cm depth. However, analysis of microsclerotia in roots showed that in years with adequate rain no difference was detected. In dry years, however, roots from plants developed under the conventional system had significantly more microsclerotia. Because of the wide host range of M. phaseolina and the long survival times of the microsclerotia, crop rotation would probably have little benefit in reducing charcoal rot. Under these study conditions it may be a better alternative to suppress charcoal rot by using the no-till cropping system to conserve soil moisture and reduce disease progress.

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Reaction of Drought-Tolerant Soybean Genotypes to Macrophomina phaseolina

Plant Health Progress ◽

10.1094/php-2008-0618-01-rs ◽

2008 ◽

Vol 9 (1) ◽

pp. 16 ◽

Cited By ~ 10

Author(s):

J. A. Wrather ◽

J. G. Shannon ◽

T. E. Carter ◽

J. P. Bond ◽

J. C. Rupe ◽

...

Keyword(s):

Drought Tolerance ◽

Common Bean ◽

Root Colonization ◽

Macrophomina Phaseolina ◽

Common Disease ◽

Charcoal Rot ◽

Stages Of Growth ◽

Drought Tolerant ◽

Soybean Genotypes ◽

Moderately Resistant

Charcoal rot caused by Macrophomina phaseolina is a common disease of many crops including common bean and soybean. Incidence and severity of charcoal rot are enhanced when plants are drought stressed. Resistance to this pathogen in some common bean genotypes was associated with drought tolerance. Resistance to M. phaseolina among soybean genotypes has not been identified, although a few have been rated moderately resistant based on less root tissue colonization by this pathogen compared to other genotypes. A few soybean genotypes have been rated as slow-wilt or drought-tolerant. The reaction of drought-tolerant soybean to M. phaseolina compared to intolerant or drought-sensitive genotypes has not been determined. Our objective was to determine if there were differences in root colonization by M. phaseolina between drought-tolerant and drought-sensitive soybean genotypes. Drought tolerance of the soybean genotypes and root colonization by M. phaseolina at the R6 and R8 stages of growth were not related in this study. Some drought-tolerant soybean genotypes may resist root colonization by M. phaseolina, but our results suggest that this is not true for all drought-tolerant genotypes. Accepted for publication 21 March 2008. Published 18 June 2008.

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