Homoserine in seedlings of the tribe vicieae of the leguminosae

Young seedlings of 10 subspecies and varieties of Pisum all accumulated high levels of homoserine, as did also Lathyrus latifolius seedlings. There was less in L. odoratus, and little or none in Cicer arietinum, Lens Culinaris, Vicia faba, and V. sativa seedlings.     

Dihydrowyerone derivatives as components of the furanoacetylenic phytoalexin response of tissues of Vicia faba

Changes in concentrations of 7 wyerone derivatives in bean tissues undergoing resistant reactions to Botrytis cinerea or B. fabae and in cotyledons in response to mercuric chloride have been examined using high performance liquid chromatography. The proportion of derivatives occurring in their saturated (dihydro) forms varied between cotyledon, leaf and pod tissues and with time after inoculation. Unsaturated derivatives were always present in greater concentrations than their dihydro analogues.     

Biosynthesis of the phytoalexin wyerone in Vicia faba

In contrast to earlier results [1-¹⁴C] acetate, [2-¹⁴C] malonate and [n 9,10-³H] oleate show significant incorporations into wyerone and related Vicia faba phytoalexins, following infection by Botrytis cinerea.     

Identification of the Erythrina phytoalexin cristacarpin and a note on the chirality of other 6a-hydroxypterocarpans

Cristacarpin, a new phytoalexin from Erythrina crista-galli is assigned the structure (?)-3,6a-dihydroxy-9-methoxy-10-γ,γ-dimethylallyl-cis-pterocarpan. It is accompanied by the known phytoalexins phaseollidin and demethylmedicarpin in this plant. Cristacarpin, phaseollidin and demethylmedicarpin were also obtained from E. sandwicensis and (together with isomedicarpin) from the related legume, Psophocarpus tetragonolobus. A compilation of selected optical rotation, NMR and conformational data for all known 6a-hydroxypterocarpans is presented and it is concluded that the previously assigned chiralities of neobanol, glyceollins I–IV and 3,6a,9-trihydroxypterocarpan should be reversed. Chirality assignments are made for a number of previously unassigned compounds.     

3,6a-Dihydroxy-8,9-methylenedioxypterocarpan as a metabolite of pisatin produced by Fusarium solani f. sp. pisi

One of the fungal metabolites of pisatin has been identified as resulting from the demethylation of pisatin at position 3.     

Biosynthesis of the 6a-hydroxypterocarpan phytoalexin pisatin in Pisum sativum

Comparative feeding experiments in cupric chloride-treated Pisum sativum pods and seedlings have demonstrated excellent incorporation into the 6a-h     

A 2-arylbenzofuran phytoalexin from cowpea (Vigna unguiculata)

2-(2′-methoxy-4′-hydroxyphenyl)-6-methoxybenzofuran (vignafuran) has been identified as the major phytoalexin from cowpea leaves infected with Colletotrichum lindemuthianum.     

Autonomous and induced pterocarpanoid formation in the leguminosae

The occurrence of pterocarpanoids (either ‘autonomously formed’ or ‘induced’) is surveyed and a chemotaxonomic evaluation is made of this and new data. A hypothesis is proposed for their biosynthetic relationships involving a pterocarp-6a-en intermediate.     

Phytoalexin induction and its chemosystematic significance in the genus Trigonella

Using the drop-diffusate technique, a number of isoflavonoid phytoalexins have been obtained from the excised, fungus-inoculated leaflets of 41 species belonging to the legume genus Trigonella. Leaf diffusates variously contained pterocarpan (medicarpin and maackiain) and isoflavan (vestitol and sativan) derivatives previously associated with genera closely allied to Trigonella. In diffusates from T. calliceras, medicarpin was accompanied by a phytoalexin (designated TC-1) provisionally identified as a new hydroxylated pterocarpan. Most of the Trigonella species were also examined for their ability to release coumarin upon tissue maceration. The combined phytoalexin/coumarin data suggest that three major intrageneric chemical divisions occur in Trigonella; two of these apparently link the genus to Medicado/Factorovskya and Melilotus respectively, whilst the third provides some evidence for a connection with Trifolium. The taxonomic aspects of these findings are discussed in the light of earlier morphological studies which provided evidence for a distinct floral dichotomy amongst Trigonella species.     

Isolation of a new isoflavan phytoalexin from two Lotus species

A phytoalexin isolated from the fungus-inoculated leaflets of Lotus angustissimus and L. edulis has been characterised as 5,7-dimethoxy-2′,4′-dihydroxyisoflavan (lotisoflavan). The total synthesis of lotisoflavan is described.     

A revised classification of the tribe Phaseoleae (Leguminosae: Papilionoideae), and its relation to canavanine distribution

The subtribal classification of the tribe Phaseoleae has drifted into disorder since Bentham's (1865) scheme in the Genera Plantarum. A revised classification is here proposed, which for the first time accounts for all of the currently recognized genera. This classification has seven subtribes: Cajaninae, Diocleinae, Kennediinae, Phaseolinae, Glycininae, Ophrestiinae, and Erythrininae, of which the Ophrestiinae is new. A survey for the free amino acid, canavanine, shows that it is most often present in the Diocleinae and Kennediinae and frequently absent in the rest of the tribe.     

A new isoflavan phytoalexin from leaflets of Lotus hispidus

A new isoflavonoid phytoalexin isolated from the fungus-inoculated leaflets of Lotus hispidus (hairy birdsfoot trefoil) has been identified as 5,4′-dimethoxy-7,2′-dihydroxyisoflavan (5-methoxyvestitol). Three known isoflavans (demethylvestitol, vestitol and sativan) are also produced by L. hispidus. The synthesis of 5-, 6- and 8-methoxyvestitol is described. Preparation of the pterocarpan analogues of 6- and 8-methoxyvestitol has allowed the structures of two additional legume phytoalexins to be unequivocally confirmed.     

A new isoflavone phytoalexin from fungus-inoculated stems of Glycine wightii

6-Isopentenylgenistein 1 (wighteone) has been isolated as a phytoalexin from the fungus-inoculated or CuCl₂-treated stems of Glycine wightii. Plants treated with aqueous CuCl₂, but not those inoculated with the fungus, also accumulated genistein (2) and its 2′-hydroxy derivative (3).     

Inducibly-formed isoflavonoids from leaves of soybean

Isoformononetin, glyceollins I, II and 2-isopentenyl-3,6a,9-trihydroxypterocarpan (glyceocarpin) accumulated in soybean (Glycine max) leaves after treatment with aqueous sodium iodoacetate or a cell suspension of the bacterium, Pseudomonas pisi. These compounds were also accompanied by two previously unreported pterocarpans, glyceofuran its 9-O-methyl derivative. Glyceocarpin is described for the first time as a plant product.     

Isoflavonoid and stilbene phytoalexins of the genus Trifolium

The fungus-inoculated leaflets of 55 Trifolium species have been examined for the presence of isoflavonoid and non-flavonoid phytoalexins. Isoflavonoid derivatives belonging to the pterocarpan (medicarpin, maackiain and 4-methoxymaackiain) and isoflavan (vestitol, isovestitol, sativan, isosativan and arvensan) classes were isolated from 50 species whilst T. campestre and T. dubium accumulated the trihydroxy stilbene, transresveratrol. Three other species (T. badium, T. scutatum and T. spadiceum) apparently did not produce phytoalexins in response to fungal inoculation. The distribution and biosynthetic relationship of Trifolium phytoalexins is discussed and the genus compared with others belonging to the Trifolieae and related tribes.     

The delimitation of the tribe Vicieae (Leguminosae) and the relationships of Cicer L.

A survey of morphological, anatomical, karyological and chemical characters has been carried out, centred on the Vicieae but extending to the neighbouring tribes Trifolieae and Ononideae. The results show that Cicer , traditionally a member of the Vicieae, has more in common with genera of the Trifolieae and Ononideae than with the rest of the Vicieae. It is proposed that Cicer should be removed from the Vicieae and recognized as the monogeneric tribe Cicereae Alef. The tribe Vicieae sensu stricto, a well-defined natural group, is delimited and described. Phylogenetic relationships of the Cicereae are discussed.     

Distribution of stizolamine in some leguminous plants

The seeds of 38 species of 29 genera in 21 tribes of the Leguminosae were screened for stizolamine. It was detected in 19 species of the subfamily Lotoideae. Its occurrence in Lotoideae was wide (82% in tribes, 56% both in genera and species) but sporadic. The content was fairly varied (0·249–9540 nmol/g of seeds), the largest amount occurring in Stizolobium hassjoo.