Phytoalexins screening

Sbaghi M, Jeandet P, Faivre B, Bessis R, Fournioux JC. 1995. Development of methods using phytoalexin (resveratrol) assessment as a selection criterion to screen grapevine in vitro cultures for resistance to grey mould (Botrytis cinerea). Euphytica 86 41-47. 

The family most intensively investigated for phytoalexins is the Legumlnosae. Well over 500 species have now been screened at Reading, using the drop-diffusate technique (9 10). This is convenient in that it provides a phytoalexin solution, free from other plant constituents. The disadvantage is that only milligram amounts are available for Identification. However, modern methods of separation and spectral analysis usually operate successfully on this scale. 

That only small amounts of phytoalexin are available usually from laboratory experiments would seem to limit the opportunities for pesticide screening. However, it is usually possible to scale up procedures to yield up to gram amounts. The placing of a suitable fungal spore suspension in opened pea pods, for example, will produce a solution from which pisatin will crystallize (<0. 

This modification did not alter the spatial positioning and the gap between the phenolic hydroxyl groups crucial for the biological activity of the phytoalexin. Five lead compounds were identified from 72 compounds synthesized and screened. 

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