Phylogenetic identification of fungi isolated from strawberry and papaya fruits and their susceptibility to fatty acids

Figures & data

Fig. 1 Phylogenetic relationship of Botrytis cinerea (AUC-ZM-1) isolated from Zamora, Michoacán, Mexico, based on a region of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene with a cut-off value of 70%.

Fig. 2 Phylogenetic relationship of Colletotrichum nymphaeae (AUC-ZM-10) isolated from Zamora, Michoacán, Mexico, and C. siamense (AUC-TC-5) isolated from Tecomán, Colima, Mexico, based on a region of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene with a cut-off value of 70%.

Fig. 3 Mycelial growth inhibition of Botrytis cinerea (A), Colletotrichum siamense (B), and C. nymphaeae (C) by fatty acids. Only those treatments that showed 100% inhibition are shown. A1, B1, and C1) Positive control: Thiabendazole. A2, B2, and C2) Absolute control: PDA + fungus. A3, B3, and C3) Negative control: Absolute ethanol for hexanoic and decanoic acid, water for sodium octanoate. A4 and A5) B. cinerea inhibition by decanoic acid (1000 and 2000 µM, respectively). B4 and B5) C. siamense inhibition by decanoic acid (1000 and 2000 µM, respectively). C4, C5, C6, C7 and C8) C. nymphaeae inhibition by hexanoic acid (2000 µM), sodium octanoate (1000 and 2000 µM, respectively), and decanoic acid (1000 and 2000 µM, respectively).

Table 1. Inhibitory effect of fatty acids on mycelial growth of Botrytis cinerea.

Fatty acid concentration (µM)	B. cinerea growth (mm)	AI (%)
Hexanoic acid (6:0) DL^&
100	-	-
1000	-	-
2000	-	-
Sodium octanoate (8:0) DS^§
100	-	-
1000	-	-
2000	-	-
Decanoic acid (10:0)
100	53 ± 0.5	0^d
1000	0 ± 0.0	100^a
2000	0 ± 0.0	100^a
Lauric acid (12:0)
100	32 ± 1.5	38.2^c
1000	27 ± 1.5	47.8^bc
2000	25 ± 1.0	51.7^b
Palmitic acid (16:0)
100	53 ± 0.0	0^d
1000	53 ± 0.0	0^d
2000	53 ± 0.0	0^d
Positive control*	1.0 ± 2.4	98^a
Absolute control**	51.7 ± 3.4	0^d
Negative control***	51.8 ± 3.2	0^d

Different letters in each column indicate significant differences between means (P ≤ 0.05).

^&DL: Determined by Leyva et al. (2008).

^§DS: Determined by Sandoval et al. (2018).

*PDA and Thiabendazole (6 mg mL⁻¹).

**PDA and fungus.

***PDA, absolute ethanol, 0.5% Tween 20, and chloroform according to the fatty acid evaluated.

Table 2. Inhibitory effect of fatty acids on mycelial growth of Colletotrichum spp.

Fatty acid concentration (µM)	C. siamense growth (mm)	AI (%)	C. nymphaeae growth (mm)	AI (%)
Hexanoic acid (6:0)
100	44.2 ± 1.6	14.5 ^cd	35.5 ± 3.0	10.5^cd
1000	44.8 ± 0.9	13.3 ^cd	33.6 ± 2.4	15.3^c
2000	41.5 ± 1.2	19.7^c	0 ± 0.0	100^a
Sodium octanoate (8:0)
100	52.3 ± 0.5	0^e	43.6 ± 0.5	0^e
1000	47.3 ± 0.5	8.5^d	0 ± 0.0	100^a
2000	45 ± 0.0	12.9^cd	0 ± 0.0	100^a
Decanoic acid (10:0)
100	53 ± 0.0	0^e	35.1 ± 0.9	11.5^cd
1000	0 ± 0.0	100^a	0 ± 0.0	100^a
2000	0 ± 0.0	100^a	0 ± 0.0	100^a
Lauric acid (12:0)
100	54 ± 0.0	0^e	39.3 ± 4.9	1.0^e
1000	53.3 ± 0.5	0^e	33.3 ± 4.5	16.1^c
2000	53 ± 0.0	0^e	35.3 ± 0.5	11.0^cd
Palmitic acid (16:0)
100	53 ± 0.0	0^e	39.1 ± 1.7	1.0^e
1000	53 ± 0.0	0^e	39.5 ± 1.5	0.5^e
2000	53 ± 0.0	0^e	39.3 ± 1.0	1.0^e
Positive control*	9.2 ± 3.8	82.2^b	12.2 ± 1.8	69.2^b
Absolute control**	51.8 ± 3.3	0^e	40.0 ± 3.6	0^e
Negative control***	51.7 ± 3.3	0.2^e	39.7 ± 3.1	0^e

Different letters in each column indicate significant differences between means (P ≤ 0.05).

*PDA and Thiabendazole (6 mg mL⁻¹).

**PDA and fungus.

***PDA, absolute ethanol, 0.5% Tween 20, chloroform, and water, according to the fatty acid evaluated.

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