Fungal Enzymes in Charcoal Rot Disease of Soybean: Repression of Exo-Polygalacturonase and Inhibition of Beta Glucosidase by Gluconolactone

1975 ◽  
Vol 82 (2) ◽  
pp. 128-137
Author(s):  
T. H. Oswald ◽  
T. D. Wyllie
Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 645 ◽  
Author(s):  
Hamed K. Abbas ◽  
Nacer Bellaloui ◽  
Cesare Accinelli ◽  
James R. Smith ◽  
W. Thomas Shier

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.


2009 ◽  
Vol 45 (No. 2) ◽  
pp. 49-58 ◽  
Author(s):  
S. El-Bramawy M A E-H ◽  
E.-S. El-Hendawy S ◽  
I. Shaban W

Since sesame accessions differ significantly in many morphological and phenotypical traits, some of these traits could be suitable for direct selection for resistance to Fusarium wilt and charcoal rot diseases. Forty-eight sesame accessions that originated from different countries were screened for their reaction to infection by <I>Fusarium oxysporum</I > f.sp. <I>sesami</I> (FOS) and <I>Macrophomina phaseolina</I> (MPH), the Fusarium wilt and charcoal rot pathogens, respectively, in 2005 and 2006. The level of infection and seed yield were measured. Number of branches and days to maturity as morphological traits and seed color as phenotypical trait, which represent some of the diversity among the accessions, were tested for possible correlation with infection percentage. We found that 57, 67 and 67% in 2005, and 77, 77 and 62% in 2006 of the accessions resistant to FOS, and 68, 77 and 64% in 2005, and 80, 76 and 60% in 2006 of the accessions resistant to MPH had a medium branch number, medium maturity and creamy seed colour. According to the analysis of regression, branch number and seed colour were significantly correlated with infection percentages by FOS and/or MPH. Therefore, these traits may be used for direct selection of sesame accessions that are resistant to Fusarium wilt and charcoal rot disease. However, no significant correlations were found between days to maturity and infection percentage by both fungi. Linear regression between infection percentage and three groups of branch number and seed colour indicated that the accessions with medium branch number and creamy or white seed colour were the only covariate which significantly correlated with the infection percentage by FOS and/or MPH.


2019 ◽  
Vol 34 (2) ◽  
pp. 124
Author(s):  
Pawan K. Amrate ◽  
M. K. Shrivastava ◽  
M. S. Bhale

1991 ◽  
Vol 69 (3) ◽  
pp. 682-685
Author(s):  
Phyllis T. Himmel

Root infections caused by Macrophomina phaseolina were initiated under optimal conditions for the host, Euphorbia lathyris. Two-week-old Euphorbia lathyris seedlings were inoculated by tying roots with cotton strings infested with Macrophomina phaseolina. Ninety-three per cent of the inoculated roots developed infections after 2 weeks incubation in silica sand at 25 °C. By using infested strings, differences in the incidence of lesion development were detected when infected roots were subjected to differing temperature regimes. After approximately 6 weeks, there was a significantly [Formula: see text] greater incidence of lesion development at 34 °C than at 25 °C, whereas there was no difference in the incidence of infection. Aerial symptoms indicative of charcoal rot were not observed during the course of these studies. Key words: infested strings, charcoal rot.


2019 ◽  
Author(s):  
Ananda Y. Bandara ◽  
Dilooshi K. Weerasooriya ◽  
Sanzhen Liu ◽  
Christopher R. Little

ABSTRACTMacrophomina phaseolina (MP) is a necrotrophic fungus that causes charcoal rot disease in sorghum [Sorghum bicolor (L.) Moench]. The host resistance and susceptibility mechanisms for this disease are poorly understood. Here, the transcriptional and biochemical aspects of the oxidative stress and antioxidant system of charcoal rot resistant and susceptible sorghum genotypes in response to MP inoculation were investigated. RNA sequencing revealed 96 differentially expressed genes between resistant (SC599) and susceptible (Tx7000) genotypes that are related to the host oxidative stress and antioxidant system. Follow-up functional experiments demonstrated MP’s ability to significantly increase reactive oxygen (ROS) and nitrogen species (RNS) content in the susceptible genotypes. This was confirmed by increased malondialdehyde content, an indicator of ROS/RNS-mediated lipid peroxidation. The presence of nitric oxide (NO) in stalk tissues of susceptible genotypes was confirmed using a NO-specific fluorescent probe (DAF-FM DA) and visualized by confocal microscopy. Inoculation significantly increased peroxidase activity in susceptible genotypes while catalase activity was significantly higher in MP-inoculated resistant genotypes. MP inoculation significantly reduced superoxide dismutase activity in all genotypes. These findings suggested MP’s ability to promote a host-derived oxidative stress response in susceptible sorghum genotypes, which contributes to induced cell death-associated disease susceptibility to this necrotrophic phytopathogen.


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