Pisum, phytoalexins

Wu, Q.D., Preisig, C.L., and VanEtten, H.D., Isolation of the cDNAs encoding (+)6a-hydro-xymaackiain 3-0-methyltransferase, the terminal step for the synthesis of the phytoalexin pisatin in Pisum sativum. Plant Mol Biol, 35, 551, 1997. 

Pisatin (6.23) is an isoflavonoid phytoalexin that is synthesized by pea (Pisum sativum L.) as a response to infection (Preisig et al., 1989). Subsequently, it was shown that pathogens capable of demethylating pisatin were tolerant of this phytoalexin. The enzyme responsible for demethylation is a specific cytochrome P450 mono-oxygenase released by the fungus Nectria haematococca (Delserone et al., 1999). 

Cruickshank, I. A.M., Perrin, D.R. Studies on phytoalexins. Ill The isolation, assay, and general properties of a phytoalexin from Pisum sativum L. Aus J Biol Sci 1961 14 336 348. 

Perrin, D.R., Bottomley, W. Studies on phytoalexins. V The structure of pisatin from Pisum sativum L. J Amer Chem Soc 1962 84 1919-1922. 

Brassica oleracea (Brassicaceae), Spinacia oleracea (Chenopodiaceae), Medicago spp., Pisum sativum, Trifolium spp. (clover) (Fabaceae) induced phytoalexin in Glycine max, Phaseolus lunatus, P. vulgaris, Vigna unguiculata (Fabaceae)... 

Even the well known Pisum system originally studied by Cruickshank and Perrin (4)has given new results. Pueppke and Van Etten in 1976 (17) found additional phytoalexins were formed, later in the Interaction after plsatln was induced. And last year,... 

Pisatin, phaseollin, 6-hydroxyphaseollin (D 22.3.3) Phytoalexins of Pisum scuiviim and Phaseolus vulgaris respectively... 

Isol. from leaves of Trifolium pratense as fungal metab. Also prod, by cultures of Ascochyta pisi, Botrytis cinerea, Fusarium spp., Nectria haematococca and other fungi. Mp 178-181° dec. -h337° (c, 0.944 in EtOH). 3-Me, 8,9-methylenedioxy ether [20186-22-5]. 6di-Hydroxy-3-methoxy-S,9-methylenedioxypterocarpan. Pisatin Stress metab. from Caragana spp., Lathyrus spp., Pisum fulvum, P. sativum, Tephrosia bidwilli and Trifolium pratense. Phytoalexin. Cryst. (EtOH or C H ). Mp 61°. [a]g +280° (c, 0.11 in EtOH). 

Sim, YJ. et al. (1991) Stereoisomerism in plant disease resistance induction and isolation of the 7,2 -dihydroxy-4 ,5 -methylenedioxyiso-flavone oxidoreductase, an enzyme introducing chirality during synthesis of isoflavonoid phytoalexins in pea (Pisum sativum L). Arch. Biochem. Biophys. 284, 167-173... 

Pterocarpans of legume plants with the properties of phytoalexins are glyceoUins in soyabeans Glycinemax), medicarpin and maack-iain in chickpeas Cicer arietinum), pisatin in pea seeds Pisum sativum) and phaseoHn in common beans Phaseolus vulgaris). Pterocarpans occur preferentially as 6"-malonylglucosids. In addition to antimicrobial effects they also exhibit other biological effects (see Section 10.3.3.5.1). 

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