Journal of Phytopathology - Phytopathologische Zeitschrift (1996) 144, 527-532

P. Sankara, P.V. Subba Rao and R.N. Strange (1996)
Differential accumulation of phytoalexins in leaves of susceptible and resistant genotypes of groundnut (Arachis hypogaea L.) inoculated with Puccinia arachidis Speg.
Journal of Phytopathology - Phytopathologische Zeitschrift 144 (11-12), 527-532
Abstract: The accumulation of phytoalexins in a rust-susceptible (KH 241-D) and a rust-resistant (PI 259747) genotype of groundnut 2, 6, 15 and 25 days after inoculation with the rust pathogen, Puccinia arachidis Speg. was investigated. Within 2 days of inoculation of the resistant genotype, total phytoalexins reached 35 µg/g fresh weight, remained close to this level for a further 13 days but reached 104 µg/g at 25 days after inoculation. In contrast, the susceptible genotype accumulated only 4 µg/g fresh weight 2 days after inoculation and this increased gradually to 13, 23 and 52 µg/g fresh weight at 6, 15 and 25 days, respectively. Extracts from uninoculated leaves of both genotypes showed the presence of an antifungal compound which appeared as a diffuse spot in the Thin Layer Chromatography (TLC) bioassay, but this was essentially absent in inoculated leaves and did not correspond to any peak detected on High Performance Liquid Chromatography (HPLC). Compounds with UV spectra corresponding to isoflavanones were the major component of the phytoalexin response whereas other phytoalexins, formononetin, daidzein, and medicarpin comprised a minor component. A further compound with a retention time of 23.0 min on HPLC and a lambda max of 280 nm only accumulated in inoculated leaves of the resistant genotype.
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Link to article at publishers website

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Puccinia arachidis	Groundnut/peanut (Arachis hypogaea)