Isosteric probes provide structural requirements essential for detoxification of the phytoalexin brassinin by the fungal pathogen Leptosphaeria maculans

Pedras, M. Soledade C.; Jha, Mukund; Okeola, Oladapo G.

doi:10.1016/j.bmc.2007.06.040

Cited by 20 publications

(13 citation statements)

References 15 publications

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“…All phytoalexins and the analogue 3-phenylindole were synthesized as described by Pedras et al (2007b).…”

Section: Phytoalexins and Analogue 3-phenylindolementioning

confidence: 99%

“…Crucifer phytoalexins can be detoxified in vitro by Leptosphaeria maculans and Leptosphaeria biglobosa (Pedras and Ahiahonu, 2005;Pedras et al, , 2007aPedras et al, , 2007b, Rhizoctonia solani, which causes root rot (Pedras and Okanga, 1999;Pedras and Khan, 2000), and S. sclerotorium (Pedras and Ahiahonu, 2002;Pedras andHossain, 2006, 2007). Moreover, similar detoxification reactions occur in planta; for example, brassinin detoxification by L. maculans in infected leaves of Brassica napus .…”

Section: Introductionmentioning

confidence: 99%

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Cloning, purification and characterisation of brassinin glucosyltransferase, a phytoalexin-detoxifying enzyme from the plant pathogen Sclerotinia sclerotiorum

Sexton

Minić

Cozijnsen

et al. 2009

Fungal Genetics and Biology

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“…All phytoalexins and the analogue 3-phenylindole were synthesized as described by Pedras et al (2007b).…”

Section: Phytoalexins and Analogue 3-phenylindolementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cloning, purification and characterisation of brassinin glucosyltransferase, a phytoalexin-detoxifying enzyme from the plant pathogen Sclerotinia sclerotiorum

Sexton

Minić

Cozijnsen

et al. 2009

Fungal Genetics and Biology

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“…Several analogues of brassinin and phytoalexins (78 compounds; see supplementary Table S1) were synthesized, purified and characterized spectroscopically, as reported previously [13,14]. The activity of BO was examined in the presence of these compounds at 0.10 m m (supplementary Table S1); the compounds showing inhibition were also tested at 0.30 m m (Table 5).…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we proposed a mechanism for the transformation of brassinin to indole‐3‐carboxaldehyde [14], which invoked the formation of an imido dithiocarbamate intermediate (I 1 ) partly resembling a cyclobrassinin structure, followed by formation of a fully conjugated intermediate (I 2 ) partly resembling a camalexin structure (Fig. 6).…”

Section: Discussionmentioning

confidence: 99%

“…Considering the apparent specificity of the enzyme involved in the oxidative detoxification of brassinin, brassinin oxidase (BO), we suggested that BO inhibitors could prevent detoxification of brassinin by L. maculans and thus avoid its depletion in infected plants [13,14]. The concomitant accumulation of brassinin and related phytoalexins might prompt a recovery in which the infected plant would be able to ward off the sensitive pathogen(s).…”

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Brassinin oxidase, a fungal detoxifying enzyme to overcome a plant defense – purification, characterization and inhibition

Pedras¹,

Minić²,

Jha³

2008

The FEBS Journal

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Microbial plant pathogens display a variety of successful strategies to invade plant tissues and obtain the necessary nutrients that allow growth and reproduction. Plants fight back with no smaller a variety of weapons, including the synthesis of small to very large molecules to inhibit specific metabolic processes in the pathogen [1][2][3]. In general, plants under microbial attack produce de novo a blend of antimicrobial defenses known as phytoalexins, the specific components of which appear to depend on the type of stress [4,5]. Despite such an arsenal, fungal pathogens can disarm the plant by counterattacking with enzymes that detoxify promptly these phytoalexins [6][7][8]. The outcome of this 'arms race ' [3] frequently favors the pathogen, causing great crop devastation and substantial yield losses. Brassinin is a phytoalexin of great importance to crucifer plants, due to its dual role both as an antimicrobial defense and a biosynthetic precursor of several other phytoalexins. The toxophore group of brassinin is a dithiocarbamate, with an interesting resemblance to the potent fungicides used in the 1960s [9]. From a plant's perspective, it is highly desirable to prevent brassinin detoxification by any pathogen.Crucifers include a wide variety of crops cultivated across the world; for example, the oilseeds rapeseed and canola (Brassica napus and Brassica rapa) and vegetables such as cabbage (Brassica oleraceae var. capitata), cauliflower (Brassica oleraceae var. botrytis) or broccoli (Brassica oleraceae var. italica). In addition, both wild and cultivated crucifers are known to Blackleg fungi [Leptosphaeria maculans (asexual stage Phoma lingam) and Leptosphaeria biglobosa] are devastating plant pathogens with well-established stratagems to invade crucifers, including the production of enzymes that detoxify plant defenses such as phytoalexins. The significant roles of brassinin, both as a potent crucifer phytoalexin and a biosynthetic precursor of several other plant defenses, make it critical to plant fitness. Brassinin oxidase, a detoxifying enzyme produced by L. maculans both in vitro and in planta, catalyzes the detoxification of brassinin by the unusual oxidative transformation of a dithiocarbamate to an aldehyde. Purified brassinin oxidase has an apparent molecular mass of 57 kDa, is approximately 20% glycosylated, and accepts a wide range of cofactors, including quinones and flavins. Purified brassinin oxidase was used to screen a library of brassinin analogues and crucifer phytoalexins for potential inhibitory activity. Unexpectedly, it was determined that the crucifer phytoalexins camalexin and cyclobrassinin are competitive inhibitors of brassinin oxidase. This discovery suggests that camalexin could protect crucifers from attacks by L. maculans because camalexin is not metabolized by this pathogen and is a strong mycelial growth inhibitor.Abbreviations BO, brassinin oxidase; CKX, cytokinin oxidase ⁄ dehydrogenase; DEA, diethanolamine; FCC, flash column chromatography; PMS, phenazine methosulfate;...

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The chemical ecology of crucifers and their fungal pathogens: Boosting plant defenses and inhibiting pathogen invasion

Pedras

2008

The Chemical Record

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Fungal plant diseases can cause very substantial yield losses in crucifer crops such as rapeseed and canola, or vegetables such as cabbage and broccoli. To devise sustainable methods to prevent and deter crucifer pathogens, the chemical interaction between crucifers and their fungi is under intense investigation. Crucifers produce complex blends of secondary metabolites with diverse ecological roles that include protection against microbial pathogens and other pests. The secondary metabolites involved in crucifer defense, namely phytoalexins and phytoanticipins, and their metabolism by fungal pathogens indicate that some fungi produce different enzymes to detoxify these metabolites and that some fungal detoxifying enzymes are rather specific. Chemical synthesis and screening of phytoalexin analogue libraries using cultures of fungal pathogens, as well as protein extracts, have shown that such detoxification reactions can be inhibited and that some inhibitors are strongly antifungal. Overall results of current work show the feasibility of using selective inhibitors of fungal detoxifying enzymes, i.e., paldoxins, to protect plants by boosting their chemical defenses.

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Isosteric probes provide structural requirements essential for detoxification of the phytoalexin brassinin by the fungal pathogen Leptosphaeria maculans

Cited by 20 publications

References 15 publications

Cloning, purification and characterisation of brassinin glucosyltransferase, a phytoalexin-detoxifying enzyme from the plant pathogen Sclerotinia sclerotiorum

Cloning, purification and characterisation of brassinin glucosyltransferase, a phytoalexin-detoxifying enzyme from the plant pathogen Sclerotinia sclerotiorum

Brassinin oxidase, a fungal detoxifying enzyme to overcome a plant defense – purification, characterization and inhibition

The chemical ecology of crucifers and their fungal pathogens: Boosting plant defenses and inhibiting pathogen invasion

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