The association of pisatin tolerance and demethylation with virulence on pea in Nectria haematococca

VanEtten, Hans D.; Matthews, Patty S.; Tegtmeier, K. J.; Dietert, Margaret F.; Stein, J.I.

doi:10.1016/0048-4059(80)90040-5

Cited by 85 publications

(46 citation statements)

References 27 publications

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“…This is consistent with previous studies which have shown that methoxylated flavonoid compounds are more fungitoxic than their nonmethoxylated precursors (VanEtten et al, 1980 ;Kodama et al, 1992 ;Aida et al, 1996).…”

Section: supporting

confidence: 82%

Temporal synthesis and radiolabelling of the sorghum 3‐deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3‐dimalonyl glucoside

Wharton

Nicholson

2000

New Phytologist

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Sorghum (Sorghum bicolor) synthesizes a complex mixture of 3-deoxyanthocyanidin phytoalexins in response to inoculation with the non-pathogenic fungus Bipolaris maydis. The anthocyanin cyanidin 3-dimalonyl glucoside, is also synthesized naturally in response to light. To determine the order and time of appearance of these compounds, etiolated sorghum mesocotyls were inoculated with B. maydis and tissue extracts were analysed by photodiode array-HPLC every 2 h for the first 24 h and at 48 h post inoculation (hpi). Uninoculated and inoculated etiolated mesocotyls were also allowed to incorporate L-[U-"%C] phenylalanine. Apigeninidin appeared at 10 hpi, followed by luteolinidin and apigeninidin 5-O-arabinoside at 14 hpi. Luteolinidin 5-methylether was not detected until 18 hpi and apigeninidin 7-methylether not until 20 hpi. The concentrations of the primary phytoalexins, apigeninidin, luteolinidin and apigeninidin 5-O-arabinoside, rose steadily between 12 and 24 hpi, and the levels of apigeninidin and luteolinidin were approximately equivalent by 24 hpi. However, between 24 and 48 hpi luteolinidin and luteolinidin 5-methylether accumulated rapidly so that by 48 hpi the amounts of luteolinidin and luteolinidin 5-methylether had increased approximately twofold. Radiolabelling also showed that "%C was incorporated into the 3-deoxyanthocyanidins and cyanidin 3-dimalonyl glucoside. Several other unidentified phenolic compounds also accumulated radioactivity.

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Section: supporting

confidence: 82%

Temporal synthesis and radiolabelling of the sorghum 3‐deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3‐dimalonyl glucoside

Wharton

Nicholson

2000

New Phytologist

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“…The fungi were isolated from diseased portions of the source plants indicated in Table 1. Isolates were provided by the following individuals (isolate number in this study, followed by donor's designation, if any): G. C. Bergstrom (10, Pm866; 11, Pm872; 12, Pm873), J. E. Carroll (14)(15)(16) (30). All fungi isolated from alfalfa and red clover were confirmed as pathogens of red clover by others.…”

Section: Methodsmentioning

confidence: 99%

“…(+)Pisatin was extracted from pea [24]. (-)Pisatin, as well as the two enantiomers of pisatin specifically radiolabelled at the 3-O-methyl position with 14 C, were prepared by methylation of (-) or (+)6a-hydroxymaackiain (6a-HM) with methyl iodide [16]. (+)6a-HM was obtained by 6a-hydroxylation of (-) maackiain by N. haematococca MP VI isolated T-95 [19].…”

Section: Methodsmentioning

confidence: 99%

“…An inhibition value of 40% was chosen as the value at which to classify a fungus as sensitive or tolerant to a phytoalexin. Based on previous studies with (+)pisatin and (-) maackiain in which this assay was used, isolates of Nectria haematococca mating population (MP) VI inhibited ≥ 40% were unable to metabolize pisatin or maackiain, and were low in virulence on pea [15][16][17] and chickpea (Cicer arietinum L.) [14,18]. In cases where multiple isolates of a species were assayed, each isolate was evaluated individually in the comparison of the responses of pathogens with non-pathogens.…”

Section: Toxicity Of Host Phytoalexinsmentioning

confidence: 99%

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Differential toxicity of enantiomers of maackiain and pisatin to phytopathogenic fungi

1992

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“…Pea HM3OMT catalyzes the final O-methylation step in pea phytoalexin biosynthesis, converting the pterocarpan 6a-hydroxymaackiain into the antimicrobial end product pisatin (Preisig et al, 1989(Preisig et al, , 1991Wu et al, 1997). This reaction is critical for resistance of pea against the fungal pathogen Nectria hematococca, virulent isolates of which possess a specific detoxifying cytochrome P450 enzyme, pisatin demethylase, located on a dispensable chromosome (VanEtten et al, 1980;Ciuffetti and VanEtten, 1996;Wasmann and VanEtten, 1996).…”

Section: Introductionmentioning

confidence: 99%

Structural Basis for Dual Functionality of Isoflavonoid O-Methyltransferases in the Evolution of Plant Defense Responses

et al. 2006

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In leguminous plants such as pea (Pisum sativum), alfalfa (Medicago sativa), barrel medic (Medicago truncatula), and chickpea (Cicer arietinum), 49-O-methylation of isoflavonoid natural products occurs early in the biosynthesis of defense chemicals known as phytoalexins. However, among these four species, only pea catalyzes 3-O-methylation that converts the pterocarpanoid isoflavonoid 6a-hydroxymaackiain to pisatin. In pea, pisatin is important for chemical resistance to the pathogenic fungus Nectria hematococca. While barrel medic does not biosynthesize 6a-hydroxymaackiain, when cell suspension cultures are fed 6a-hydroxymaackiain, they accumulate pisatin. In vitro, hydroxyisoflavanone 49-O-methyltransferase (HI49OMT) from barrel medic exhibits nearly identical steady state kinetic parameters for the 49-O-methylation of the isoflavonoid intermediate 2,7,49-trihydroxyisoflavanone and for the 3-O-methylation of the 6a-hydroxymaackiain isoflavonoid-derived pterocarpanoid intermediate found in pea. Protein x-ray crystal structures of HI49OMT substrate complexes revealed identically bound conformations for the 2S,3R-stereoisomer of 2,7,49-trihydroxyisoflavanone and the 6aR,11aR-stereoisomer of 6a-hydroxymaackiain. These results suggest how similar conformations intrinsic to seemingly distinct chemical substrates allowed leguminous plants to use homologous enzymes for two different biosynthetic reactions. The three-dimensional similarity of natural small molecules represents one explanation for how plants may rapidly recruit enzymes for new biosynthetic reactions in response to changing physiological and ecological pressures.

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The association of pisatin tolerance and demethylation with virulence on pea in Nectria haematococca

Cited by 85 publications

References 27 publications

Temporal synthesis and radiolabelling of the sorghum 3‐deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3‐dimalonyl glucoside

Temporal synthesis and radiolabelling of the sorghum 3‐deoxyanthocyanidin phytoalexins and the anthocyanin, cyanidin 3‐dimalonyl glucoside

Differential toxicity of enantiomers of maackiain and pisatin to phytopathogenic fungi

Structural Basis for Dual Functionality of Isoflavonoid O-Methyltransferases in the Evolution of Plant Defense Responses

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