5.6.8
EFFECT OF SOME NOVEL ANTIFUNGALS ON DIFFERENT PATHOGENIC FUNGI

C FANELLI1, AA FABBRI1, S MONTI1, R MENICAGLI2, D PIN2 SM RAPACCINI2, S SAMARITANI2 and P SALVADORI2

1Dipartimento di Biologia Vegetale, Universita di Roma 'La Sapienza', Largo Cristina di Svezia 24, 00165 Roma, Italy; 2Dipartimento di Chimica e Chimica Industrials, Universita di Pisa, Via Risorgimenti 35, 56120 Pisa, Italy

Background and objectives
Chemicals are one of the most widely used methodologies to control plant pathogenic fungi [1, 2]. The preliminary results on the inhibiting effect of some novel antifungals on conidia germination and growth after germination of some plant pathogens is reported.

Materials and methods
The novel compounds assayed were: (i) some different trisubstituted 1,3,5 triazines (signalled 1, 2 and 3); (ii) two macrocyclic structures containing two 1,3,5 triazine units (signalled 4 and 5); (iii) two modified coumarines (signalled 6 and 7).
The compounds assayed were: 1=(R)-2,4,6-tri[3'-N'(1"-a-naphtylethyi)aminopropyllamino-1,3,5-triazine; 2=(S)-2,4,6-tri[3'-N(1"-phenylethyl)aminopropyllamino-1,3,5-triazine; 3=(1"R)-1"a-naphtylethyl]aminopropyl]amino-6-n.hexylamino-l,3,5-triazine. 4=(S)-4,29-di(1'ciclohexylethyl)amino-5,8,20,23 tetraoxa 2,11,13,15,17,26,28,30,31,32decaazatricyclo[25.3. 1. 1. ]dotriaconta-1(31),12,14,16(32),27,29 hexaene; 5=(S)-14,29-di(1'phenylethyl)amino 5,8,20,23-tetraoxa2,11,13,15,17,26,28,30,31,32decaazatricyclo[25.3.1. 1.]dotriaconta-1 (31),12,14,16(32),27,29 hexaene; 6=(3R,S)6,8-dihydroxy-3-hydroxymethyl-3-4-dihydroisocoumarine; 7=(3R,S)8-hydroxy-3 hydroxymethyl-6-methoxy-3,4-dihydroiso-coumarine.
The pathogenic fungi tested were: < i>Fusariun graminearum, Colletotrichum lindemuthianum and the aflatoxigenic Aspergillus parasiticus. All the compounds were tested at various concentrations. Conidia of the fungi tested were inoculated in 2 ml of potato dextrose broth and incubated until 5 days at 27C in the presence or absence of antifungals. In other experiments, germinated conidia were incubated in the presence of the antifungals.

Results and conclusions
Conidial germination of F. graminearum was completely inhibited until 5 days in the presence of antifungals 1, 2 and 3. Other similar compounds were effective until 3 days of incubation. All the compounds tested on F. graminearum were inhibitory to C. lindemuthianum. The conidial germination of A. parasiticus in the presence of 2 and 3 were only slowed. The antifungals 1 and 3 completely stopped the growth of germinated conidia of F. graminearum and C. lindemuthianum. In contrast, A. parasiticus appeared to be resistant. Compound 4 inhibited the germination of all tested fungi, and 4 and 5 are effective in inhibiting fungal growth until 2-3 days of incubation. The compounds 6 and 7 appear to be effective on F. graminearum and C. lindemuthianum, but not on A. parasiticus. These results show that the novel assayed antifungals are promising inhibitors of the tested plant pathogens.

References
1. Brent KJ, 1996. In Modern Fungicides and Antifungal Compounds. pp. 3-15.
2. De Waard MA, Georgopoulos SG, Hollomon DW et al., 1993. Annual Review of Phytopathology 31, 403-427.