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Elicitation and Suppression of Phytoalexin and Isoflavone Accumulation in Cotyledons of Cicer arietinum L. as Caused by Wounding and by Polymeric Components from the Fungus Ascochyta rabiei
Author(s) -
Kessmann H.,
Barz W.
Publication year - 1986
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1986.tb04370.x
Subject(s) - phytoalexin , elicitor , formononetin , biology , isoflavones , biochanin a , isoflavonoid , fungus , botany , mycelium , colletotrichum lindemuthianum , ascochyta , biochemistry , genistein , phaseolus , flavonoid , antioxidant , blight , daidzein , resveratrol , endocrinology , gene
Shortly after sowing cotyledons of chickpea ( Cicer arietinum ) start to accumulate the isoflavones biochanin A and formononetin together with their 7‐0‐glucosides and their 7‐0‐glucoside‐6″‐malonates. The additional accumulation of the pterocarpan phytoalexins medicarpin and maackiain can be induced by wounding of the cotyledons. Treatment of sliced cotyledons with a crude elicitor fraction obtained from the growth medium or the mycelium of the chickpea pathogenic fungus Ascochyta rabiei (Pass.) Lab. leads to a dramatic increase in the level of numerous aromatic compounds, especially of the isoflavone aglyca and the phytoalexins. Accumulation of isoflavone conjugates is not altered by elicitor treatment as shown by time course studies, and dose‐response curves. A protein preparation (“suppressor”) isolated from the culture filtrate of the same fungus was shown to inhibit the accumulation of isoflavone aglyca, isoflavone conjugates and phytoalexins in the sliced cotyledons. The possible relevance of elicitor‐suppressor counteraction with regard to the defence mechanisms of the host plant is discussed.