Involvement of an extracellular fungus laccase in the flavonoid metabolism in Citrus fruits inoculated with Alternaria alternata

Díaz, Licinio; Rı́o, José Antonio del; Pérez‐Gilabert, Manuela; Ortuño, A.

doi:10.1016/j.plaphy.2015.02.006

Cited by 15 publications

(9 citation statements)

References 35 publications

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“…2C). Second, we added an inhibitor to DOC plant to block the activity of laccases, a common family of soil enzymes capable of oxidizing flavonoid structures (23). Similar to heat treatment, this enzymatic inhibitor did not alter naringenin (unpaired t test, P > 0.05; Fig.…”

Section: Downloaded Frommentioning

confidence: 97%

Soil organic matter attenuates the efficacy of flavonoid-based plant-microbe communication

et al. 2020

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Plant-microbe interactions are mediated by signaling compounds that control vital plant functions, such as nodulation, defense, and allelopathy. While interruption of signaling is typically attributed to biological processes, potential abiotic controls remain less studied. Here, we show that higher organic carbon (OC) contents in soils repress flavonoid signals by up to 70%. Furthermore, the magnitude of repression is differentially dependent on the chemical structure of the signaling molecule, the availability of metal ions, and the source of the plant-derived OC. Up to 63% of the signaling repression occurs between dissolved OC and flavonoids rather than through flavonoid sorption to particulate OC. In plant experiments, OC interrupts the signaling between a legume and a nitrogen-fixing microbial symbiont, resulting in a 75% decrease in nodule formation. Our results suggest that soil OC decreases the lifetime of flavonoids underlying plant-microbe interactions.

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Section: Downloaded Frommentioning

confidence: 97%

Soil organic matter attenuates the efficacy of flavonoid-based plant-microbe communication

et al. 2020

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“…The strong pathogenicity of the Alt14 isolate was also associated with a higher expression of the laccase enzyme, considered as a virulence factor of this fungus [8]. This enzyme could be responsible for the browning of the fruit peel (albedo and flavedo) observed when 'Fortune' fruits are inoculated with this fungus, forming part of an enzymatic complex capable of oxidizing the phenolic…”

Section: Discussionmentioning

confidence: 99%

“…For laccase enzyme extracts, the A. alternata was cultivated in Saboreaud liquid medium (SIGMA) (peptone 10 g/L, D-glucose 40 g/L, pH 5.6 +/− 0.2) supplemented with 5 mM Cu 2 SO 4 [17] in 250 mL flasks and the culture was kept in a growth chamber at 25 • C, in darkness and stirring at 170 rpm [8].…”

Section: Selection Of Alternaria Alternata Isolates Culture Of the Fmentioning

confidence: 99%

“…Laccase activity was measured at 25 • C using 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (20 mM) as substrate [18]. The reaction was followed by measuring the increase in absorbance at 436 nm (ε = 29300 M −1 cm −1 ) in a UNICAM UV 500 spectrophotometer (Thermo Electronics, Cambridge, UK) according to a previously described procedure [8]. One unit of laccase activity was defined as the amount of enzyme required to oxidize 1 µmol of ABTS per minute at 25 • C in the standard reaction medium.…”

Section: Extraction and Measurement Of Laccase Activity In The Mycelimentioning

confidence: 99%

“…Some studies reveal that the differences in the susceptibility of Citrus fruits to A. alternata are due to complex endogenous signaling processes, modulated by several factors, such as ethylene produced during infection, the fruit growth stage, the phytoanticipins and/or phytolaexins present or induced in the fruits, and changes in laccase activity-a virulence factor of the fungus produced during infection [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of the Alternaria alternata Pathogenicity in ‘Fortune’ Mandarin

2018

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Alternaria brown spot, caused by Alternaria alternata (Fr.) Keissl, is an important disease in tangerines and their hybrids, affecting leaves, twigs, and immature fruit. Differences in susceptibility to this pathogenic fungus have been described for different Citrus species. In this paper, the expression of the mycotoxins alternariol and alternariol monomethyl ether in different A. alternata isolates was analyzed by HPLC-MS. A correlation was observed between the mycotoxins content and the pathogenicity of each isolated of A. alternata used, suggesting that the mycotoxins may be involved in the evolution of brown spot in ‘Fortune’ fruits caused by this fungus. The increased expression of the above mycotoxins was associated with the end of mycelia growth, high sporulation, and an increase in hyphal melanization in the fungus. On the other hand, the presence of laccase activity in the xylem of ‘Fortune’ fruits inoculated with A. alternata suggests that this is the way the fungus propagates in the plant. These results add to our knowledge of the pathogenesis of A. alternata in Citrus.

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Occurrence and characterization of Alternaria alternata causing leaf spot of soybean (Glycine max) in Pakistan

Buzdar,

Ahmed,

Awan

et al. 2023

J Plant Pathol

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Involvement of an extracellular fungus laccase in the flavonoid metabolism in Citrus fruits inoculated with Alternaria alternata

Cited by 15 publications

References 35 publications

Soil organic matter attenuates the efficacy of flavonoid-based plant-microbe communication

Soil organic matter attenuates the efficacy of flavonoid-based plant-microbe communication

Mechanism of the Alternaria alternata Pathogenicity in ‘Fortune’ Mandarin

Occurrence and characterization of Alternaria alternata causing leaf spot of soybean (Glycine max) in Pakistan

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