Rhizospheric bacteria for use in preventing Fusarium wilt and crown root rot of tomato under natural field conditions

Figures & data

Table 1. Soil composition of four different fields.

	Soil component
Field	Organic matter (%)	Phosphorus mg kg^−1	Potassium mg kg^−1	Calcium mg kg^−1	Magnesium mg kg^−1	Sodium mg kg^−1	Nitrate mg kg^−1	pH	EC^e (mS cm^−1)
Site A^a	1.20	10.65	585	3930	510	167.9	50	7.5	1.32
Site B^b	1.74	15.20	585	3700	480	161.0	100	7.5	1.5
Site C^c	1.55	12.36	546	4272	510	167.9	100	7.4	0.21
Site D^d	1.52	18.65	604.5	3596	504	167.9	100	7.0	0.15

a Agricola Doña Alicia, Batamote, Guasave

b CIIDIR-Sinaloa field station, Guasave

c Agricola Doña Alicia, Batamote, Guasave

d Agricola Doña Alicia, Guayparime, Guasave

e Electrical conductivity (EC)

Table 2. Geographic and agronomic information for the experimental fields from Sinaloa, Mexico.

Site	Growing season	Location	Geographic coordinates	Soil type	Altitude
A^a	2018–2019	Agrícola Doña Alicia, Batamote, Guasave	25°42′29.26′′N, 108°36′41.17′′W	Loam	27 m
B^a	2018–2019	CIIDIR-Sinaloa field station, Guasave	25°32′50.02′′N, 108°28′43.04′′W	Silty clay loam	15 m
C^a	2019–2020	Agrícola Doña Alicia, Batamote, Guasave	25°40ʹ14.2”N, 108°38ʹ10.8”W	Clay loam	15 m
D^a	2019–2020	Agrícola Doña Alicia, Guayparime, Guasave	25°36ʹ12.8”N, 108°31ʹ27.2”W	Silty clay loam	12 m

^aThe experimental fields were selected on the basis of visually estimating the presence or absence of disease signs caused by Fol races 1, 2, 3 and Forl in the previous agronomic cycle, as suspected for Agrícola Doña Alicia. The experimental site A was changed for the second field trial (2019–2020) due to the lack of adequate land, and site B was changed based on the tomato grower at Agrícola Doña Alicia. Soil types were detected by using the triangular texture diagram proposed by the USDA.

Table 3. Tomato plant transplant and harvest dates, including agricultural management information, for the field trials conducted at four sites in two consecutive growing seasons. All tomato hybrids were susceptible to Fol race 3 and Forl and resistant to Fol races 0–2, except hybrid SV8579TE. The hybrid SV8579TE was resistant to all races of Fol. Tomato fruits were collected at different times while the producer harvested. The disease incidence and severity of infected plants were calculated by the end of the cycle (hybrid Tisey: 119 days; DRD 8551: 180 days; SV8579TE: 209 days; and hybrid Katya: 117 days).

Site	Growing season	Hybrid		Plant transplant and harvest date
		Determinate	Indeterminate		Fungicide^e	AI^f and Dosage (ha^−1)	Insecticide^e	AI and Dosage (ha^−1)	Hormone^e	AI and Dosage (ha^−1)
A^a	2018–2019		DRD 8551, Seminis, USA	09/27/2018 – 03/29/2019	Amistar gold	Azoxistrobin 300 g	Agrimec	Abamectina 360 g	Agi 3	Gibberellic acid 60 g
B^b	2018–2019		Tisey, Seminis,USA		Cabrio c	Boscalisd + piraclostrobin 700 g	Belt	Flubendiamide 0.5 L
				09/25/2018 – 01/21/2019
C^c	2019–2020		SV8579TE, Seminis, USA		Eco 720	Clorotalonil 1.5 L	Decis forte	Deltametrina 15 cc
				09/25/2019 – 04/21/2020
D^d	2019–2020	Katya, Hazera, USA			Fontelis	Pentiopirad 2 L	Letal	Acetamiprid 150 g
				11/03/2019 – 03/10/2020
					Manzate	Mancozeb 1 Kg	Movento	Spirotetramat 400 mL
					Metanil	Metalaxil 2 Kg
					Sanazole	Propiconazole 700 mL
					Score	Difeconazole 0.5 L
					Umbral	Copper gluconate 60 mL
					Zoll	Tebuconazole 250 mL

^aAgrícola Doña Alicia, Batamote, Guasave

^bCIIDIR-Sinaloa field station, Guasave

^cAgrícola Doña Alicia, Batamote, Guasave

^dAgrícola Doña Alicia, Guayparime, Guasave

^eAll these agrochemicals were applied post-transplanting during tomato cultivation in three different fields (Site B, C and D). No agrochemicals were applied in field Site A.

^fActive ingredient (AI)

Table 4. Trial I. Plant growth-promotion and biocontrol effect of four antagonistic bacterial strains (AcDB3, BtMB9, BsTA16 and BaMA26) in two different tomato hybrids (DRD 8551 and Tisey) against natural Fol R3 and Forl inoculum and infection conditions in two different fields, during the 2018–2019 growing season. The two experimental fields are Site A: Agrícola Doña Alicia, and Site B: the CIIDIR-Sinaloa experimental field station.

Treatment	FW^b incidence^d (%)	FW^b severity (%)	FCRRT^c incidence^d (%)	FCRRT^c severity (%)	Stem diameter (mm)	Fruit yield (kg per plant)
Site A) Agrícola Doña Alicia (Batamote)
Hybrid DRD 8551
CTL^a	60 ± 0 a	24.2 ± 0.3 a	67 ± 3 a	36.7 ± 0.7 a	15.0 ± 0.5 a	6.23 ± 0.38 e
AcDB3	33 ± 6 ab	8.3 ± 0.3 b	47 ± 7 ab	13.3 ± 0.3 b	18.5 ± 0.6 e	8.93 ± 0.37 d
BtMB9	43 ± 3 ab	11.0 ± 0.3 b	47 ± 3 ab	14.2 ± 0.5 b	18.2 ± 0.6 de	9.85 ± 0.52 cd
BsTA16	27 ± 3 b	6.7 ± 0.3 b	40 ± 0 b	11.6 ± 0.3 b	17.6 ± 0.6 cde	12.94 ± 0.47 ab
BaMA26	30 ± 0 ab	9.2 ± 0.3 b	47 ± 3 ab	14.2 ± 0.7 b	16.7 ± 0.5 bcd	9.78 ± 0.43 cd
AcDB3 + BsA16	33 ± 3 ab	10.8 ± 0.3 b	43 ± 3 ab	12.5 ± 0.0 b	15.2 ± 0.5 ab	11.72 ± 0.45 abc
AcDB3 + BaMA26	33 ± 7 ab	8.3 ± 0.5 b	37 ± 3 b	10.0 ± 0.5 b	15.5 ± 0.5 ab	10.65 ± 0.53 cd
BtMB9 + BsTA16	30 ± 6 b	7.5 ± 0.5 b	50 ± 6 ab	15.8 ± 0.3 b	16.4 ± 0.4 abc	11.52 ± 0.50 bc
BtMB9 + BaMA26	30 ± 6 b	7.5 ± 0.5 b	53 ± 3 ab	15.8 ± 0.5 b	15.8 ± 0.5 ab	± 0.72 a
Site B) CIIDIR-Sinaloa
Hybrid Tisey
CTL^a	57 ± 3 a	20.0 ± 0.9 a	73 ± 3 a	32.5 ± 0.5 a	10.0 ± 0.3 b	1.58 ± 0.16 b
BtMB9	47 ± 3 a	13.3 ± 0.5 a	50 ± 6 a	13.3 ± 0.3 b	11.7 ± 0.3 a	2.05 ± 0.17 ab
BaMA26	54 ± 3 a	14.2 ± 0.3 a	43 ± 12 a	11.7 ± 1.1 b	12.3 ± 0.3 a	2.37 ± 0.13 a
BtMB9 + BaMA26	60 ± 10 a	15.0 ± 0.5 a	60 ± 6 a	25.0 ± 0.3 ab	11.4 ± 0.3 a	2.47 ± 0.13 a

^aNon-inoculated control

^bFusarium wilting

^cFusarium crown and root rot of tomato

^dIncidence (%) data was subjected to natural logarithm transformation before statistical analysis

AcDB3: Acinetobacter calcoaceticus; BtMB9: B. thuringiensis; BsTA16: B. subtilis; BaMA26: B. amyloliquefaciens. ± indicates standard error (SE). The different lowercase letters (a-e) indicate statistical differences between treatments (P ≤ 0.05).

Table 5. Trial II. Plant growth-promotion and biocontrol effect of four antagonistic bacterial strains (AcDB3, BtMB9, BsTA16 and BaMA26) in two different tomato hybrids (SV8579TE and Katya) against natural Fol R3 and Forl inoculum and infection conditions in two different fields, during the 2019–2020 growing season. The two experimental fields are Site C: Agrícola Doña Alicia (Batamote), and Site D: Agrícola Doña Alicia (Guayparime).

Treatment	FW^b incidence^d (%)	FW^b severity (%)	FCRRT^c incidence^d (%)	FCRRT^c severity (%)	Stem diameter (mm)	Fruit yield (kg per plant)
Site C) Agrícola Doña Alicia (Batamote)
Hybrid SV8579TE
CTL^a	60 ± 6 a	15.46 ± 0.34 a	57 ± 3 a	32.5 ± 0.46 a	11.58 ± 0.45 e	3.28 ± 0.17 d
AcDB3	17 ± 3 b	4.16 ± 0.26 b	40 ± 6 a	10.83 ± 0.69 b	12.59 ± 0.39 de	5.70 ± 0.19 abc
BtMB9	20 ± 0 b	5.00 ± 0.46 b	40 ± 10 a	11.67 ± 0.69 b	14.35 ± 0.49 a	5.32 ± 0.18 bc
BsTA16	20 ± 6 b	5.00 ± 0.65 b	30 ± 6 a	8.33 ± 0.53 b	14.15 ± 0.36 ab	5.94 ± 0.15 a
BaMA26	23 ± 9 b	5.00 ± 0.46 b	37 ± 9 a	10.00 ± 0.79 b	13.62 ± 0.30 abcd	5.74 ± 0.20 ab
AcDB3 + BsA16	17 ± 7 b	4.16 ± 0.52 b	47 ± 3 a	11.67 ± 0.26 b	13.04 ± 0.38 cd	5.76 ± 0.19 ab
AcDB3 + BaMA26	20 ± 6 b	5.00 ± 0.46 b	37 ± 14 a	10.83 ± 1.39 b	13.21 ± 0.35 bcd	5.68 ± 0.17 abc
BtMB9 + BsTA16	23 ± 7 b	5.00 ± 0.45 b	27 ± 3 a	9.17 ± 0.26 b	13.80 ± 0.31 abc	5.34 ± 0.15 bc
BtMB9 + BaMA26	17 ± 7 b	4.16 ± 0.53 b	33 ± 7 a	10.00 ± 0.45 b	13.56 ± 0.31 abcd	5.21 ± 0.16 c
Site D) Agrícola Doña Alicia (Guayparime)
Hybrid Katya
CTL^a	70 ± 8 a	30.37 ± 1.01 a	77 ± 3 a	39.17 ± 0.263 a	14.38 ± 0.37 d	9.29 ± 0.14 e
AcDB3	47 ± 3 ab	11.67 ± 0.26 b	43 ± 3 b	11.67 ± 0.264 b	15.94 ± 0.44 bc	13.98 ± 0.20 ab
BtMB9	37 ± 3 b	10.00 ± 0.79 b	40 ± 0 b	10.83 ± 0.527 b	17.21 ± 0.40 a	13.33 ± 0.20 c
BsTA16	47 ± 7 ab	11.67 ± 0.69 b	53 ± 3 ab	15.83 ± 0.697 b	16.69 ± 0.37 ab	13.95 ± 0.19 b
BaMA26	43 ± 7 ab	15.00 ± 0.45 b	50 ± 6 b	14.17 ± 0.527 b	15.47 ± 0.43 c	12.94 ± 0.20 cd
AcDB3 + BsA16	57 ± 7 ab	16.67 ± 0.69 b	53 ± 7 ab	15.00 ± 0.697 b	15.35 ± 0.38 cd	14.09 ± 0.16 ab
AcDB3 + BaMA26	33 ± 7 b	10.00 ± 0.45 b	50 ± 0 b	16.67 ± 0.263 b	15.07 ± 0.37 cd	14.47 ± 0.11 a
BtMB9 + BsTA16	37 ± 3 b	11.67 ± 0.26 b	57 ± 7 ab	15.83 ± 0.456 b	16.90 ± 0.32 ab	12.55 ± 0.19 d
BtMB9 + BaMA26	43 ± 3 ab	14.17 ± 0.69 b	53 ± 3 ab	15.00 ± 0.456 b	15.86 ± 0.33 bc	12.84 ± 0.18 cd

^aNon-inoculated control

^bFusarium wilting

^cFusarium crown and root rot of tomato

^dIncidence (%) data was subjected to natural logarithm transformation before statistical analysis

AcDB3: Acinetobacter calcoaceticus; BtMB9: Bacillus thuringiensis; BsTA16: B. subtilis; BaMA26: B. amyloliquefaciens. ± indicates standard error (SE). The different lowercase letters (a-e) indicate statistical differences between treatments (P ≤ 0.05).

Fig. 1 Biplot of principal component analysis. Factor loadings (unrotated) extraction: principal components (marked loadings are > 0.700000). SA = Site A: Agrícola Doña Alicia (Batamote); SC = Site C: Agrícola Doña Alicia (Batamote); SD = Site D: Agrícola Doña Alicia (Guayparime); FW = fruit weight; SD = stem diameter; IFW = incidence of Fusarium wilt; IFCRRT = incidence of Fusarium crown and root rot of tomato; SFW = severity of Fusarium wilt; SFCRRT = severity of Fusarium crown and root rot of tomato.