Estimation of the root colonization of soybean by an arbuscular mycorrhizal fungus, Gigaspora rosea, based on specific fatty acid profiles

Figures & data

Table 1. The intensity of AM fungal colonization in the second lateral root of soybeans at 6 and 9 weeks after sowing (%, n = 5).

	6 WAS	9 WAS
Enrei AM	76.8 ± 2.52^a	86.7 ± 2.67^a
Enrei RAM	48.9 ± 6.46^b	71.7 ± 0.69^b
Kanto100 AM	73.8 ± 2.48^a	90.4 ± 1.85^a
Kanto100 RAM	77.9 ± 2.76^a	92.4 ± 1.43^a

AM: inoculation with AM fungus alone; RAM: inoculation with rhizobium and AM fungus. For each sampling period, different letters indicate significant differences as assessed by Tukey-Kramer test (P < 0.05) after performing one-way ANOVA.

Table 2. Fatty acid profiles in the first lateral root of soybeans at 6 and 9 weeks after sowing (%, n = 5).

	6 WAS						9 WAS
	Enrei			Kanto100			Enrei			Kanto100
Fatty acids	Control	AM	RAM	Control	AM	RAM	Control	AM	RAM	Control	AM	RAM
12:0	0.46 ± 0.01	0.50 ± 0.04	0.51 ± 0.05	0.44 ± 0.02	0.52 ± 0.06	0.86 ± 0.11	0.46 ± 0.03	0.31 ± 0.03	0.29 ± 0.01	0.63 ± 0.10	0.38 ± 0.04	0.44 ± 0.03
C9 dicarboxylic acid	0.63 ± 0.02	0.51 ± 0.05	0.51 ± 0.06	0.64 ± 0.09	0.55 ± 0.01	0.95 ± 0.08	0.50 ± 0.02	0.29 ± 0.01	0.30 ± 0.01	0.54 ± 0.03	0.41 ± 0.01	0.53 ± 0.05
14:0	1.01 ± 0.04	0.99 ± 0.09	1.02 ± 0.10	1.03 ± 0.06	1.03 ± 0.07	1.80 ± 0.06	1.00 ± 0.09	0.67 ± 0.09	0.78 ± 0.03	1.18 ± 0.21	0.52 ± 0.03	0.92 ± 0.07
15:1ω6	0.55 ± 0.01	0.45 ± 0.01	0.42 ± 0.02	0.58 ± 0.02	0.50 ± 0.01	0.55 ± 0.02	0.67 ± 0.02	0.36 ± 0.02	0.33 ± 0.01	0.66 ± 0.01	0.34 ± 0.01	0.36 ± 0.02
15:0	0.87 ± 0.02	0.72 ± 0.02	0.72 ± 0.03	0.95 ± 0.04	0.81 ± 0.04	1.07 ± 0.03	0.51 ± 0.06	0.37 ± 0.06	0.52 ± 0.03	0.77 ± 0.11	0.32 ± 0.02	0.62 ± 0.03
16:1ω7	0.83 ± 0.09	0.40 ± 0.10	0.17 ± 0.10	0.11 ± 0.11	–	0.44 ± 0.28	0.13 ± 0.14	0.30 ± 0.09	0.15 ± 0.11	1.01 ± 0.53	–	0.08 ± 0.06
16:1ω5	–	–	–	–	–	–	–	–	–	–	–	–
16:0	19.66 ± 0.37	21.82 ± 0.36	20.82 ± 0.43	19.34 ± 0.44	21.42 ± 0.30	23.70 ± 1.31	16.90 ± 0.14	28.09 ± 1.06	25.31 ± 0.76	15.96 ± 0.25	28.35 ± 0.47	28.85 ± 1.05
17:0	0.70 ± 0.02	0.51 ± 0.01	0.51 ± 0.01	0.94 ± 0.02	0.57 ± 0.02	0.59 ± 0.01	0.79 ± 0.03	0.44 ± 0.01	0.48 ± 0.02	0.74 ± 0.03	0.34 ± 0.01	0.40 ± 0.03
16:0 2OH	1.58 ± 0.02	1.54 ± 0.02	1.41 ± 0.10	1.63 ± 0.10	1.56 ± 0.05	1.94 ± 0.11	1.41 ± 0.03	0.86 ± 0.05	0.84 ± 0.05	1.55 ± 0.06	0.97 ± 0.02	1.15 ± 0.11
18:3ω4,6,12	–	0.41 ± 0.03	0.35 ± 0.03	–	0.43 ± 0.02	0.47 ± 0.01	–	0.38 ± 0.02	0.36 ± 0.01	0.19 ± 0.12	0.40 ± 0.01	0.40 ± 0.01
18:2ω6,9/a18:0	23.26 ± 0.15	21.81 ± 0.42	22.76 ± 0.60	22.82 ± 0.72	22.47 ± 0.42	20.29 ± 1.12	25.88 ± 0.39	20.12 ± 0.63	22.15 ± 0.59	23.54 ± 1.07	18.59 ± 0.52	15.99 ± 0.34
18:1ω9	22.32 ± 0.34	22.76 ± 0.18	23.08 ± 0.56	22.47 ± 1.01	24.46 ± 0.56	20.25 ± 0.91	22.48 ± 0.47	22.11 ± 0.53	22.52 ± 0.25	23.14 ± 1.10	21.54 ± 0.55	18.99 ± 0.56
18:1ω7/ω9t/ω12t	–	–	–	–	–	–	–	–	–	–	–	–
18:0	3.44 ± 0.09	3.20 ± 0.08	3.20 ± 0.08	3.49 ± 0.14	3.01 ± 0.08	3.39 ± 0.13	2.99 ± 0.10	4.07 ± 0.15	4.06 ± 0.13	2.87 ± 0.07	3.74 ± 0.10	4.04 ± 0.14
18:1ω9 DMA	1.44 ± 0.03	1.41 ± 0.02	1.40 ± 0.04	1.51 ± 0.09	1.44 ± 0.03	1.10 ± 0.08	1.42 ± 0.04	1.03 ± 0.04	1.12 ± 0.02	1.39 ± 0.10	0.87 ± 0.06	0.71 ± 0.03
19:1ω8t	11.46 ± 0.20	10.01 ± 0.32	10.03 ± 0.41	11.01 ± 0.48	10.77 ± 0.26	13.69 ± 0.27	13.00 ± 0.41	7.70 ± 0.57	9.56 ± 0.60	13.83 ± 0.66	11.27 ± 0.65	12.69 ± 0.94
18:0 2OH	6.72 ± 0.17	5.83 ± 0.13	5.99 ± 0.21	6.95 ± 0.31	5.08 ± 1.27	1.64 ± 1.54	7.60 ± 0.19	4.43 ± 0.24	4.40 ± 0.23	8.16 ± 0.20	4.81 ± 0.18	6.40 ± 0.48
18:1 2OH	–	–	–	–	–	–	–	–	–	–	–	–
20:4ω6	–	–	–	–	–	–	–	0.37 ± 0.02	0.25 ± 0.10	–	0.45 ± 0.02	0.44 ± 0.01
20:5ω3	–	0.28 ± 0.12	–	–	0.33 ± 0.08	0.35 ± 0.09	–	0.54 ± 0.03	0.45 ± 0.04	–	0.67 ± 0.04	0.56 ± 0.01
18:0 3OH	–	0.41 ± 0.17	–	–	0.38 ± 0.15	–	–	1.00 ± 0.03	0.70 ± 0.17	–	1.16 ± 0.06	1.09 ± 0.04
C20 N alcohol	2.44 ± 0.61	3.04 ± 0.32	4.00 ± 0.56	2.60 ± 0.19	1.99 ± 0.09	3.80 ± 0.42	2.72 ± 0.07	2.43 ± 0.08	2.58 ± 0.09	2.42 ± 0.05	1.30 ± 0.07	2.05 ± 0.12
22:2ω6,9	0.99 ± 0.40	0.77 ± 0.47	0.58 ± 0.41	1.96 ± 0.14	0.33 ± 0.35	0.62 ± 0.36	–	–	–	–	–	–
20:2ω6	–	0.30 ± 0.26	–	–	–	–	–	0.67 ± 0.11	0.26 ± 0.10	–	0.55 ± 0.15	0.34 ± 0.14
20:1ω9	–	0.87 ± 0.04	1.21 ± 0.24	–	0.97 ± 0.28	1.07 ± 0.35	–	2.23 ± 0.28	1.31 ± 0.18	–	2.06 ± 0.13	1.74 ± 0.11
20:0	1.64 ± 0.05	1.46 ± 0.02	1.30 ± 0.06	1.70 ± 0.06	1.37 ± 0.05	1.42 ± 0.08	1.44 ± 0.06	1.21 ± 0.03	1.27 ± 0.06	1.42 ± 0.04	0.95 ± 0.04	1.20 ± 0.09

M ± SE; –: not detected.

Control: Non-inoculation; AM: inoculation with AM fungus alone; RAM: inoculation with rhizobium and AM fungus.

Table 3. Fatty acid profiles in the second lateral root of soybeans at 6 and 9 weeks after sowing (%, n = 5).

	6 WAS						9 WAS
	Enrei			Kanto100			Enrei			Kanto100
Fatty acids	Control	AM	RAM	Control	AM	RAM	Control	AM	RAM	Control	AM	RAM
12:0	–	0.54 ± 0.02	0.58 ± 0.05	–	0.57 ± 0.04	0.94 ± 0.02	0.61 ± 0.02	0.27 ± 0.02	0.30 ± 0.02	0.72 ± 0.12	0.39 ± 0.01	0.51 ± 0.05
C9 dicarboxylic acid	–	1.02 ± 0.06	0.87 ± 0.12	1.33 ± 0.32	0.87 ± 0.07	1.59 ± 0.07	1.14 ± 0.08	0.41 ± 0.05	0.44 ± 0.03	1.09 ± 0.07	0.68 ± 0.04	1.01 ± 0.10
14:0	0.37 ± 0.29	0.87 ± 0.05	0.88 ± 0.07	0.91 ± 0.35	0.87 ± 0.07	1.63 ± 0.12	1.29 ± 0.07	0.45 ± 0.04	0.68 ± 0.01	1.30 ± 0.25	0.44 ± 0.01	0.93 ± 0.07
15:1ω6	–	0.32 ± 0.02	0.34 ± 0.03	–	0.32 ± 0.01	0.36 ± 0.01	0.62 ± 0.01	0.12 ± 0.04	0.22 ± 0.02	0.60 ± 0.02	0.16 ± 0.04	0.22 ± 0.01
15:0	0.36 ± 0.28	0.95 ± 0.05	0.89 ± 0.12	0.67 ± 0.37	0.75 ± 0.05	1.23 ± 0.11	0.96 ± 0.08	0.28 ± 0.04	0.50 ± 0.05	1.08 ± 0.14	0.28 ± 0.02	0.62 ± 0.04
16:1ω7	–	0.59 ± 0.06	0.45 ± 0.10	–	0.35 ± 0.01	0.52 ± 0.32	0.34 ± 0.20	0.42 ± 0.03	0.44 ± 0.05	1.37 ± 0.67	0.30 ± 0.07	0.39 ± 0.10
16:1ω5	–	0.04 ± 0.05	–	–	0.04 ± 0.04	0.13 ± 0.05	–	0.15 ± 0.04	0.10 ± 0.04	–	0.09 ± 0.05	0.17 ± 0.05
16:0	22.65 ± 0.63	35.36 ± 0.65	29.72 ± 1.99	22.39 ± 0.46	29.01 ± 0.84	38.99 ± 0.86	22.71 ± 0.75	42.41 ± 1.25	40.81 ± 0.85	21.52 ± 0.52	39.68 ± 0.97	48.27 ± 1.71
17:0	–	0.44 ± 0.03	0.51 ± 0.06	–	0.41 ± 0.01	0.56 ± 0.03	1.03 ± 0.05	0.07 ± 0.03	0.26 ± 0.02	0.95 ± 0.03	0.04 ± 0.03	0.21 ± 0.01
16:0 2OH	2.07 ± 0.50	1.85 ± 0.09	1.63 ± 0.19	2.51 ± 0.09	1.58 ± 0.06	2.20 ± 0.08	1.94 ± 0.11	0.81 ± 0.03	0.92 ± 0.08	2.04 ± 0.08	0.97 ± 0.02	1.36 ± 0.08
18:3ω4,6,12	–	0.46 ± 0.04	0.46 ± 0.05	0.31 ± 0.43	0.47 ± 0.02	0.42 ± 0.01	0.21 ± 0.09	0.51 ± 0.03	0.40 ± 0.01	0.37 ± 0.04	0.56 ± 0.02	0.49 ± 0.03
18:2ω6,9/a18:0	17.75 ± 0.61	13.68 ± 0.31	17.39 ± 1.37	18.13 ± 0.99	15.53 ± 0.45	8.62 ± 0.82	19.33 ± 0.65	9.95 ± 0.63	11.01 ± 0.63	18.72 ± 1.38	11.26 ± 0.48	3.49 ± 0.40
18:1ω9	16.14 ± 0.78	17.43 ± 0.37	19.50 ± 0.84	16.29 ± 0.78	17.44 ± 0.51	12.73 ± 0.78	15.76 ± 0.98	20.22 ± 0.55	19.65 ± 0.34	16.15 ± 0.76	19.31 ± 0.33	14.36 ± 0.15
18:1ω7/ω9t/ω12t	–	–	–	–	–	1.99 ± 0.14	–	–	–	–	–	1.51 ± 0.68
18:0	3.44 ± 0.21	5.41 ± 1.22	3.86 ± 0.16	3.23 ± 0.14	3.32 ± 0.11	4.77 ± 0.10	4.00 ± 0.18	4.43 ± 0.15	4.79 ± 0.12	3.86 ± 0.13	4.12 ± 0.13	5.05 ± 0.13
18:1ω9 DMA	–	0.68 ± 0.03	0.86 ± 0.08	–	0.77 ± 0.05	0.36 ± 0.11	0.84 ± 0.07	0.43 ± 0.06	0.43 ± 0.03	0.81 ± 0.08	0.39 ± 0.02	–
19:1ω8t	16.15 ± 0.51	6.19 ± 0.39	7.82 ± 0.84	16.63 ± 0.58	6.67 ± 0.06	7.34 ± 0.24	12.76 ± 0.27	5.16 ± 0.54	4.93 ± 0.37	12.57 ± 0.33	7.17 ± 0.31	6.04 ± 0.61
18:0 2OH	10.35 ± 0.42	4.60 ± 0.19	5.53 ± 0.50	11.61 ± 0.32	5.11 ± 0.06	4.46 ± 1.13	9.71 ± 0.33	3.22 ± 0.22	3.67 ± 0.23	9.81 ± 0.34	4.03 ± 0.18	4.23 ± 0.43
18:1 2OH	–	–	–	–	–	0.09 ± 0.09	–	0.22 ± 0.09	0.21 ± 0.09	–	0.08 ± 0.07	0.48 ± 0.03
20:4ω6	–	0.46 ± 0.03	0.32 ± 0.11	–	0.51 ± 0.02	0.56 ± 0.02	–	0.72 ± 0.08	0.59 ± 0.04	–	0.69 ± 0.06	0.68 ± 0.08
20:5ω3	–	0.67 ± 0.05	0.47 ± 0.11	–	0.67 ± 0.04	0.52 ± 0.03	–	1.13 ± 0.08	0.77 ± 0.04	–	1.11 ± 0.08	0.88 ± 0.10
18:0 3OH	–	1.48 ± 0.09	0.99 ± 0.24	–	1.38 ± 0.04	1.46 ± 0.05	–	1.75 ± 0.09	1.48 ± 0.08	–	1.73 ± 0.06	1.83 ± 0.11
C20 N alcohol	7.49 ± 0.60	2.79 ± 0.24	3.38 ± 0.72	5.99 ± 0.72	2.69 ± 0.24	3.21 ± 0.29	4.86 ± 0.70	1.93 ± 0.26	2.80 ± 0.19	5.53 ± 0.60	1.91 ± 0.40	2.13 ± 0.09
22:2ω6,9	–	–	–	–	–	–	–	–	–	–	–	–
20:2ω6	–	0.51 ± 0.04	0.33 ± 0.12	–	0.53 ± 0.01	0.52 ± 0.03	–	0.63 ± 0.05	0.55 ± 0.03	–	0.60 ± 0.03	0.61 ± 0.02
20:1ω9	–	2.42 ± 0.17	1.90 ± 0.38	–	2.13 ± 0.06	3.43 ± 0.21	–	3.51 ± 0.23	3.21 ± 0.20	–	3.27 ± 0.11	3.82 ± 0.11
20:0	–	1.24 ± 0.07	1.33 ± 0.08	–	1.32 ± 0.08	1.36 ± 0.06	1.88 ± 0.08	0.83 ± 0.04	1.13 ± 0.07	1.50 ± 0.31	0.76 ± 0.03	0.77 ± 0.14

M ± SE; –: not detected.

Control: Non-inoculation; AM: inoculation with AM fungus alone; RAM: inoculation with rhizobium and AM fungus.

Figure 1. Correlation between the percentage of specific fatty acids derived from the arbuscular mycorrhizal (AM) fungus, Gigaspora rosea, and the intensity of the AM fungal colonization in the second lateral soybean roots. AM-specific fatty acids: the total of 20:1ω9, 20:4ω6, and 20:5ω3.

Figure 2. Changes in the percentage of specific fatty acids derived from arbuscular mycorrhizal (AM) fungus, Gigaspora rosea, in the first lateral roots (a) and the second lateral roots (b) of soybean plants at 6 and 9 weeks after sowing (%, n = 5). Enrei AM: Enrei with AM fungus alone; Enrei RAM: Enrei with rhizobium and AM fungus; Kanto100 AM: Kanto100 with AM fungus alone; Kanto100 RAM: Kanto100 with rhizobium and AM fungus; AM-specific fatty acids: the total of 20:1ω9, 20:4ω6, and 20:5ω3. For each sampling time point, different letters indicate significant differences as assessed by the Tukey–Kramer test (P < 0.05) after a one-way ANOVA. The absence of letters for a given sampling time point indicates no significant difference between the corresponding means.