Abstract This study consisted of determining the effect of Bacillus strains inoculated alone or in combination with phytopathogenic fungi on the production of human health-related compounds and volatile organic compounds (VOCs) in tomato fruits. Seedlings were cultivated under greenhouse conditions and inoculated with B. amyloliquefaciens, B. methylotrophicus and B. subtilis alone or in combination with Alternaria solani, Fusarium oxysporum and Phytophthora infestans. Fully ripe fruits were harvested and evaluated for carotenoid, phenol and VOCs contents. Lycopene was the most abundant carotenoid (46.4-167.62 µg/g), followed by β-carotene and lutein. Fruits from plants inoculated with Bacillus had the highest carotenoid content. In contrast, phytopathogens decreased the carotenoid contents, especially the lycopene content. The content of total phenols ranged from 0.42 to 0.90 mg GAE/g. The content of these compounds increased 1.5-fold in fruits from plants inoculated with Bacillus strains, especially those treated with B. methylotrophicus, but the greatest increase (1.9-fold) was observed in plants inoculated with phytopathogens. Both Bacillus strains and pathogens increased the antioxidant capacity, with a 2.8-fold increase compared to the control. Thirty-two VOCs were identified in the tested tomatoes. The Bacillus strains caused an increase in the concentration of VOCs, which could be associated with an increase in fruit quality.

Abstract As an alternative control method, to improve control and to reduce synthetic fungicide use, three Candida oleophila strains and/or four commercial synthetic fungicides were used to control Botrytis cinerea damage on postharvest apple fruit. Synthetic commercial fungicides; Cyprodinil+Fludioxonil, Thiabendazole and Benomyl, allowed Candida oleophila strains colony growth when challenged to the pressure of these fungicides. Synthetic commercial fungicide Captan did not allow any Candida oleophila strains colony growth. Control of Botrytis cinerea expressed in % of damage and damage reduction, gave an average control of; 100% for Cyprodinil+Fludioxonil; Captan, 97.5%; Thiabendazole, 94.1% and Benomyl, 93.7% All Candida oleophila strains, individually, gave a 100% control. Thiabendazole and Benomyl improved their efficiency to control Botrytis cinerea when combined with Candida oleophila. Control of Botrytis cinerea damage on postharvest Golden Delicious apple fruit can be achieved up to 100% either with Candida oleophila strains individually and/or with Cyprodinil+Fludioxonil alone. The use of Candida oleophila as an alternative method to control Botrytis cinerea damage on postharvest apple fruit means a reduction of synthetic fungicide use, plus avoiding fungicide residues on the treated apple fruit and on the environment, thus reducing the risk for human health damage.

Resumen Un método alternativo de control, para incrementar el control y para reducir el uso de fungicidas sintéticos, tres cepas de Candida oleophila y/o cuatro fungicidas sintéticos comerciales fueron utilizados para el control del daño provocado por Botrytis cinerea en manzana en poscosecha. Los fungicidas sintéticos; Cyprodinil+Fludioxonil, Tiabendazol y Benomilo, permitieron el crecimiento de las cepas de Candida oleophila cuando fueron sometidas a la presión de éstos. El fungicida Captan no permitió el crecimiento de ninguna de las cepas de Candida oleophila. El control del daño provocado por Botrytis cinerea expresado en % y reducción de éste, promedió un control del; 100% para el Cyprodinil+Fludioxonil; Captan, 97.5%; Tiabendazol, 94.1 y Benomilo, 93.7%. Todas las cepas de Candida oleophila, individualmente, controlaron al 100%. El Tiabendazol y el Benomilo mejoraron su control contra Botrytis cinerea cuando se combinaron con Candida oleophila. Un control del 100% del daño provocado por Botrytis cinerea en manzana Golden Delicious en poscosecha se logra utilizando las cepas de Candida oleophila de manera individual o con Cyprodinil+Fludioxonil solo. El uso de Candida oleophila como un método alternativo para el control del daño provocado por Botrytis cinerea en manzana en poscosecha significa una reducción del uso de fungicidas sintéticos, evitando también la presencia de residuos del fungicida en la manzana tratada y en el medio ambiente, reduciendo así el riesgo de daño para humanos.

Abstract: Mortierella species were isolated on Potato Dextrose Agar and V8-agar as well as mature pear fruits and azalea leaves as substrate baits. Four hundred and nineteen Mortierella isolates were obtained from soil samples in Chihuahua, Mexico which were classified into 21 groups, according to their morphological characters. Mortierella was isolated more frequently when pear fruits were used, obtaining 143 isolates (34.1%), followed by the V8-agar-antibiotics medium with 133 isolates (31.7%), and azalea leaves with 95 isolates (22.7%). An isolate from each of the 21 groups was identified molecularly, 12 corresponded to Mortierella alpina, one to M. gamsii, one to M. capitata, and six to Mortierella sp., and one belonged to the Mortierelliales order. In addition, the putative pathogenicity of the 21 Mortierella isolates identified was tested in G30 apple rootstocks under greenhouse conditions and none was pathogenic. These species have not been reported previously in Mexico. The study showed that there are Mortierella species in the rhizosphere of apple trees in Chihuahua Mexico. These fungal isolates might produce polyunsaturated fatty acids and exert effects of elicitation in horticultural plants and fruit trees improving their resistance to multiple pathogens.

Resumen: Se aislaron especies de Mortierella en Agar Dextrosa Papa y agar V8, así como peras maduras y hojas de azalea, como sustratos trampa. Se obtuvieron 419 aislados de Mortierella, de muestras de suelo en Chihuahua, México, los cuales se clasificaron en 21 grupos de acuerdo con sus caracteres morfológicos. Mortierella se aisló con mayor frecuencia cuando se emplearon peras, obteniendo 143 aislados (34.1%), seguido del agar V8-antibióticos con 133 aislados (31.7%) y las hojas de azalea, con 95 aislados (22.7%). Se identificó molecularmente un aislado de cada uno de los 21 grupos, 12 correspondieron a Mortierella alpina, uno a M. gamsii, uno a M. capitata y seis a Mortierella sp. y uno perteneció al orden Mortierelliales. Adicionalmente se probó la patogenicidad putativa de los 21 aislados de Mortierella identificados, en porta injertos de manzana G30 bajo condiciones de invernadero y ninguno fue patogénico. Estas especies no habían sido reportadas previamente en México. El estudio demostró que existen especies de Mortierella en la rizosfera de manzanos en Chihuahua, México. Estas podrían producir ácidos grasos poliinsaturados y ejercer efectos elicitores en cultivos hortofrutícolas confiriéndoles resistencia a múltiples patógenos.

Abstract The incidence of root diseases was estimated in apple orchards from Chihuahua, Mexico. Three hundred isolates (fungi and Oomycetes) were identified in samples of root tissue and soil of trees with infectious damage symptoms and disease symptom-free trees. At the same time, putatively antagonistic agents were isolated and subsequently identified. The pathogenicity of fifteen selected isolates (eight fungi and seven Oomycetes), was tested in twelve apple rootstocks under greenhouse conditions. In addition, the in vitro antagonistic activity of Trichoderma and Bacillus species was evaluated against seven of the selected Oomycetes. The incidence of infection damage of roots in 20 tested orchards was 17% (1-40%). Fusarium was the most widely distributed fungi (67.8%). The distribution of the other organisms was variable. Four species of Trichoderma were identified, with T. gamsii being the most widely distributed (72.5%). Bacillus spp. substantially reduced the radial growth (>90%, p=0.05) of Phytophthora cactorum. Eleven rootstocks were susceptible to Pythium ultimum y Phytophthora cactorum C3. The G.935, Standard and M.25 rootstocks were the most resistant with 0% incidence. The antagonistic species of both genera inhibited the in vitro growth of P. cactorum (86.4-93.8%, p= 0.05), respect to Pythium species, and therefore, they might be used as biological control agents.

Resumen Se estimó la incidencia de enfermedades de raíz en manzanos de Chihuahua, México, y se identificaron trescientos aislados (hongos y Oomicetos) tomados del tejido de raíz y suelo de la rizosfera de árboles con síntomas de infección y libres de síntomas de enfermedad. Paralelamente, se aislaron e identificaron hongos putativamente antagonistas. Se determinó la patogenicidad de quince aislados seleccionados (ocho hongos y siete Oomicetos) sobre doce portainjertos de manzano bajo condiciones de invernadero. Adicionalmente, se evaluó la actividad antagónica in vitro de especies de Trichoderma y Bacillus contra siete de los Oomicetos seleccionados. La incidencia de daños infecciosos en raíz en 20 huertos analizados fue del 17% (1-40%). Fusarium fue el hongo más ampliamente distribuido (67.8%). La distribución del resto de los organismos fue variable. Se identificaron cuatro especies de Trichoderma, siendo T. gamsii la más ampliamente distribuida (72.5%). Bacillus spp., redujo sustancialmente el crecimiento radial (>90%, p=0.05) de Phytophthora cactorum. Once portainjertos fueron susceptibles al menos a Pythium ultimum y Phytophthora cactorum C3. Los portainjertos G.935, Standard y M.25 fueron los más resistentes con 0% de incidencia. Las especies antagonistas de ambos géneros inhibieron in vitro significativamente el crecimiento de P. cactorum (86.4-93.8%, p= 0.05), respecto a especies de Pythium, por lo que podrían ser utilizados como agentes de control biológico.

Three strains of Candida oleophila and their combination were evaluated for nutrient competition as a mode of action for the biocontrol of Penicillium expansum and Botrytis cinerea. C. oleophila treatments reduced germination of conidia of both pathogens when challenged on 1% 'Golden Delicious' apple juice. P. expansum conidia germination was 1x10(7) mL-1 and B. cinerea conidia germination was 5x10(5) mL-1. C. oleophila treatments lowered conidia germination from 2-7x10(4) mL-1 for P. expansum and from 1-4x10(4) for B. cinerea. C. oleophila treatments reduced conidia germination on an average of 99% for P. expansum and 96% for B. cinerea. Sugar consumption for L07 rugose was of 0.026 mg mL-1 against B. cinerea and of 0.056 mg mL¹ against P. expansum. Sugar consumption supports conidia germination reduction. P. expansum consumed 1.69 μg L-1 of proteins, while L07 rugose consumed the greatest amount with 47.95 μg L-1. B. cinerea consumed 8.95 μg L-1 and L06 consumed 36.89 μg L-1, which was statistically equal to that of L07 rugose with 27.96 μg L-1. C. oleophila strains biocontrol B. cinerea and P. expansum, in part, by nutrient competition.

Tres cepas de Candida oleophila y su combinación, se evaluaron para determinar la competencia por nutrientes, como modo de acción para el biocontrol de Penicillium expansum y Botrytis cinerea. Los tratamientos con C. oleophila redujeron la germinación de conidios de ambos patógenos, al ser enfrentadas en jugo de manzana 'Golden Delicious' al 1%. Conidios de P. expansum germinaron a 1x10(7) mL-1 y conidios de B. cinerea germinaron a 5x10(5) mL-1. Los tratamientos con C. oleophila disminuyeron la germinación de conidios de 2-7x10(4) mL-1 para P. expansum y de 1-4x10(4) para B. cinerea. Los tratamientos con C. oleophila redujeron la germinación de conidios con promedios de 99% para P. expansum y de 96% para B. cinerea. Los azúcares consumidos por L07 rugosa fueron de 0.026 mg mL-1 contra B. cinerea y de 0.056 mg mL-1 contra P. expansum. El consumo de azúcares corrobora la reducción de germinación de conidios. P. expansum consumió 1.69 μg L-1 de proteínas, mientras que L07 rugosa consumió la mayor cantidad con 47.95 μg L-1. B. cinerea consumió 8.95 μg L-1 y L06 36.89 μg L-1, que fue estadísticamente igual al de L07 rugosa con 27.96 μg L-1. Las cepas de C. oleophila, ejercieron un biocontrol de B. cinerea y P. expansum, en parte, por competencia de nutrientes.