Baseline Sensitivity of Florida Isolates of Penicillium digitatum to Imazalil

Plant Disease ◽  
1989 ◽  
Vol 73 (9) ◽  
pp. 773 ◽  
Author(s):  
G. Eldon Brown
Keyword(s):  
Penicillium Digitatum ◽  
Baseline Sensitivity

Toxic action and baseline sensitivity of boscalid against Penicillium digitatum

2020 ◽  
Vol 137 ◽  
pp. 105272
Author(s):  
Qianru Xu ◽  
Kunyu Zhang ◽  
Yanping Fu ◽  
Hongju Ma ◽  
Fuxing Zhu
Keyword(s):  
Penicillium Digitatum ◽  
Toxic Action ◽  
Baseline Sensitivity

Fungicidal Actions and Resistance Mechanisms of Prochloraz to Penicillium digitatum

Plant Disease ◽  
2020 ◽  
pp. PDIS-05-20-1128
Author(s):  
Yuchao Zhang ◽  
Bao Zhang ◽  
Chaoxi Luo ◽  
Yanping Fu ◽  
Fuxing Zhu
Keyword(s):  
Cell Membrane ◽  
Target Genes ◽  
Membrane Integrity ◽  
Point Mutations ◽  
Resistance Mechanisms ◽  
Penicillium Digitatum ◽  
Cell Membrane Permeability ◽  
Baseline Sensitivity ◽  
Cell Membrane Integrity ◽  
Citrus Groves

The demethylation inhibitor (DMI) fungicide prochloraz has been widely used in China to control citrus green mold, which is caused by Penicillium digitatum. The 50% effective concentration (EC50) values of prochloraz for 129 isolates of P. digitatum collected in 2017 from citrus groves of four provinces of China ranged from 0.0032 to 0.4582 mg/liter. Analysis of the distribution of natural logarithms of EC50 values indicated that 111 isolates with EC50 values lower than 0.05 mg/liter could be considered sensitive to prochloraz. Relative baseline sensitivity was established based on the 111 sensitive isolates, and the mean EC50 value was 0.0090 ± 0.0054 mg/liter (SD). Prochloraz at 60, 100, and 140 mg/liter provided preventive efficacies of 67.8, 93.0, and 96.4%, respectively. Prochloraz at 0.005 and 0.01 mg/liter disrupted cell membrane integrity of conidia but reduced cell membrane permeability of mycelia. Prochloraz at 0.01 mg/liter reduced ergosterol content in mycelia by 41.8%. Two prochloraz-resistant isolates with EC50 values of 3.97 and 5.68 mg/liter were attained by consecutive subculturing on prochloraz-amended PDA. Studies on the expression levels of three potential target genes, CYP51A, CYP51B, and CYP51C, demonstrated that whether in the absence or presence of prochloraz, only CYP51B in the resistant isolates was overexpressed at least 10-fold higher than that of the sensitive ones. Sequencing of the three genes showed that only CYP51B in the resistant isolates had a 199-bp insertion in the promoter region. In addition, only CYP51B displayed point mutations of G405S, G389C, and Y390S in the coding regions in the resistant isolates. These results were important for understanding the resistance mechanisms of P. digitatum to prochloraz.

Pyrimethanil Sensitivity and Resistance Mechanisms in Penicillium digitatum

Plant Disease ◽  
2020 ◽  
Author(s):  
Yuchao Zhang ◽  
Yanping Fu ◽  
Chaoxi Luo ◽  
Fuxing Zhu
Keyword(s):  
Target Genes ◽  
Sodium Dodecyl ◽  
Resistance Mechanisms ◽  
Penicillium Digitatum ◽  
Cross Resistance ◽  
Postharvest Diseases ◽  
Cell Wall Degrading Enzymes ◽  
Baseline Sensitivity ◽  
Nucleotide Mutation ◽  
Resistant Mutants

Pyrimethanil is an anilinopyrimidines (AP) fungicide and highly effective in controlling green mold caused by Penicillium digitatum but has not yet been registered in China to control postharvest diseases of citrus. In the present study, baseline sensitivity of P. digitatum to pyrimethanil was established based on the effective concentrations for 50% inhibition (EC50) values of 127 isolates collected from five major citrus-growing regions of China. The distribution of these EC50 values was unimodal but with a long right tail. The mean EC50 value was 0.137 ± 0.046 μg/mL (SD), and the minimum and maximum were 0.073 and 0.436 μg/mL, respectively. Pyrimethanil in potato dextrose agar (PDA) at 0.20 μg/mL decreased methionine production in the mycelia by 21.6% and reduced the activities of cell wall-degrading enzymes cellulase and pectinase by 9.1 and 32.8%, respectively. Twelve pyrimethanil-resistant mutants were obtained by consecutive sub-culturing of 12 arbitrarily selected sensitive isolates on pyrimethanil-amended PDA for 4 generations, and the resistance factors ranged from 69 to 3421. There was no cross-resistance between pyrimethanil and prochloraz (r = 0.377, P = 0.123). Compared with their parental isolates, pyrimethanil-resistant mutants had reduced pathogenicity to citrus fruit but higher tolerance to hydrogen peroxide. No differences were detected in tolerance to NaCl, CaCl2, Congo red, or sodium dodecyl sulfate (SDS). Exogenous addition of methionine into PDA partially alleviated the toxicity of pyrimethanil to the sensitive isolates but had no significant effect on toxicity to the resistant mutants. Sequencing of cystathionine γ-synthase encoding genes CGS1 and CGS2, the potential target genes for pyrimethanil, showed that there was no nucleotide mutation in the coding region of CGS of the pyrimethanil-resistant mutants. However, the relative expression of CGS1 and CGS2 genes of the pyrimethanil-resistant mutants was reduced by 42.5 and 57.4%, respectively. These results have important implications for applications of pyrimethanil to control P. digitatum and for understanding the modes of action and resistance mechanisms of pyrimethanil.

Controle in vitro de Penicillium digitatum com extrato vegetal de Bidens pilosa L.

Textura ◽  
2018 ◽  
Vol 11 (20) ◽  
pp. 43-47
Author(s):  
Marilene Junqueira Machado ◽  
Noelma Miranda de Brito ◽  
Vânia de Jesus Santos ◽  
Lavinia dos Santos Mascarenhas
Keyword(s):  
Penicillium Digitatum ◽  
Bidens Pilosa

Antifungal effect of cinnamaldehyde, eugenol and carvacrol nanoemulsion against Penicillium digitatum and application in postharvest preservation of citrus fruit

LWT ◽  
2021 ◽  
Vol 141 ◽  
pp. 110924
Author(s):  
Ruopeng Yang ◽  
Jinyu Miao ◽  
Yuting Shen ◽  
Nan Cai ◽  
Chunpeng Wan ◽  
...  
Keyword(s):  
Citrus Fruit ◽  
Penicillium Digitatum ◽  
Antifungal Effect

scholarly journals Biosynthesis of ethylene from methionine. Isolation of the putative intermediate 4-methylthio-2-oxobutanoate from culture fluids of bacteria and fungi

1979 ◽  
Vol 182 (3) ◽  
pp. 827-836 ◽  
Author(s):  
D C Billington ◽  
B T Golding ◽  
S B Primrose
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mass Spectroscopy ◽  
Aeromonas Hydrophila ◽  
Penicillium Digitatum ◽  
Yeast Saccharomyces Cerevisiae ◽  
Coryneform Bacterium ◽  
Corynebacterium Species ◽  
Bacteria And Fungi

Methods are described for identifying the 2,4-dinitrophenylhydrazones of 4-methylthio-2-oxobutanoate by means of t.l.c., n.m.r. and mass spectroscopy. By using these methods 4-methylthio-2-oxobutanoate, a putative intermediate in the biosynthesis of ethylene from methionine, has been identified in culture fluids of Aeromonas hydrophila B12E and a coryneform bacterium D7F grown in the presence of methionine. Relative to 4-methylthio-2-oxobutanoate, the yield of 3-(methylthio)propanal (methional) from the same cultures was less than 1%. Because 4-[2H]methylthio-2-oxobutanoate was obtained from cultures grown on [Me-2H]methionine, the 4-methylthio-2-oxobutanoate must be derived from methionine. By means of t.l.c. alone, 4-methylthio-2-oxobutanoate was identified in the culture fluids of a range of bacteria, the yeast Saccharomyces cerevisiae and the fungus Penicillium digitatum. A photochemical assay developed for 4-methylthio-2-oxobutanoate shows it to be a product of the metabolism of methionine by Escherichia, Pseudomonas, Bacillus, Acinetobacter, Aeromonas, Rhizobium and Corynebacterium species.

Sign in / Sign up

Export Citation Format

Share Document