Alternaria solani

Ichihara A., Oikawa H. Biosynthesis of Phytotoxins From Alternaria Solani... 

Early blight, Alternaria solani Kuhn., is a problem in some areas, particularly in. warmer climates where potato growth is not optimum. Control can be obtained by protective sprays, particularly with the organics that have been recommended for late blight control. 

Fungicide activity towards Alternaria solani (tomato parasite) Fig. 6. Hydrogen bonds induced by CF2H compounds [32]. 

Alternaria solani (33) contains an unsaturated lactone moiety with a side chain (C15) and this lactone, termed alter-naric acid, exhibits inhibitory properties in seedling growth of test plants. Some of the unsaturated lactones described above are summarized in Table 3. 

The question whether Diels-Alder reactions also occur in nature can not be answered yet since special enzymes catalyzing these reactions have not been found so far [24-25]. However, artificial catalytic antibodies for Diels-Alder reactions are well known [26] and recently an all-carbon [4 + 2]cycloaddition has been observed in the biosynthesis of two phytotoxic solanopyrones 1-1 and 1-2 from the fungus Alternaria solani using a cell-free extract of this organism [27] it is highly probable that the involved enzymes will soon be isolated (Fig. 1-2). 

Alternaria solani is a plant pathogen and the causitive agent of early blight in solanum species. It produces numerous polyke-tides, such as solanopyrone A 51 and alternaric acid 52, and it... 

Alternaria solani, the causal organism of early blight disease of tomato and potato produces several metabolites whose structures have been clarified. It was pointed out that the fungus also secretes host-specific toxins which induce necrotic symptoms typically associated with the disease [50]. Five phytotoxins were isolated, solanapyrones A (67), B (68), C (69), D (70) and E (71), Fig. 17. The diastereomeric... 

In the experiments, 2,4,6-trichlorophenoxyacetic acid, pentachlorophenoxyace-tic acid and pentachlorophenoxyisobutyric acid revealed a systemic action against Botrytis fabea and Alternaria solani. Fungicides of more favourable action were obtained with such derivatives of phenoxi compounds in which the carbonyl group has also been changed. 4-Chloro-3,5-dimethylphenoxy ethanol (26), effective... 

---