Browsing by Subject "Bacterial diversity"

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    Combined effects of reduced irrigation and water quality on the soil microbial community of a citrus orchard under semi-arid conditions
    (Elsevier, 2016-11) Bastida, F.; Torres, I.F.; Romero Trigueros, Cristina; Baldrian, P.; Vetrovský, T.; Bayona, J.M.; Alarcón, J.J.; Hernández, T.; García, C.; Nicolás, E.; Ingeniería Química
    Sustainable agriculture in Mediterranean areas is compromised by the structural deficit of water resources. Under this situation, the impacts of alternative water managements on the microbial community, as a critical component of the soil quality, need to be properly understood. We evaluated the longterm impacts of irrigation systems differing on the quantity and quality of water, and their interactions, on the biomass (phospholipid fatty acid analysis), diversity and composition (16S rRNA gene profiling), and enzyme activities of the soil microbial community of an orchard cultivated with grapefruit trees in South-East Spain. The impact of water quantity was evaluated by irrigation with optimal amount of water or by irrigation with a reduced volume of water in the temporal frame when the crop is less sensitive, so-called regulated deficit irrigation (RDI). The impact of water quality was evaluated attending to the source of the irrigation water: water from a river channel-transfer (TW) or reclaimed water from a wastewater treatment plant (RW). Electrical conductivity was higher in soils irrigated with RW than in soils irrigated with TW. The content of total organic C in the soil was affected by water quality but not by water quantity. Soils irrigated with TW showed higher total organic C than soils irrigated with RW. As in the case of plant productivity, RDI had a negative impact on plant productivity, soil microbial biomass and enzyme activities in summer. This finding indicates a slow-down of organic matter decomposition under restricted irrigation. Bacterial biomass was more sensitive to RDI when RW was used, whereas the fungal biomass was more sensitive to RDI when TW was used. Bacterial diversity and plant productivity were more sensitive to water quantity than to water quality. The increase of the abundance of Proteobacteria and Bacteroidetes in soils irrigated with RW in summer suggested a higher resilience of this treatment mediated by copiotrophic organisms. A recovery of the enzyme activity and microbial biomass of soils irrigated with RW and RDI was observed in January and June. The resilience of biogeochemical and the microbial biomass processes after RDI coursed through changes in the structure of the microbial community as revealed by the multivariate analyses of fatty acids. The utilisation of reclaimed water during RDI promoted a more-resilient community that translated into a recovery of microbial biomass and enzyme activities after the water restriction ended. These results imply potential ecological benefits of the irrigation with reclaimed water that should be considered under the water limitation predicted in climate change models in Mediterranean areas.
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    Efecto de la temperatura sobre la microbiota del insecto comestible acheta domesticus
    (Facultad de Veterinaria y el Servicio de Publicaciones de la Universidad de Murcia, 2023) Beltran Soro, Leonardo; Bravo Peña, Yolanda; Galián Albadalejo, Jose
    La microbiota de los insectos desempeña funciones esenciales en el metabolismo de los mismos, contribu-yendo al correcto funcionamiento del sistema inmune y favoreciendo la digestión. La especie de grillo Acheta do-mesticus ha sido recientemente autorizada para consumo humano. La producción masiva de esta especie implica grandes costes energéticos en la zona de cría, por lo que variaciones en la temperatura de la sala pueden suponer un importante ahorro en el coste de producción. Este estudio tiene como objetivo analizar la influencia de la tempe-ratura en la composición de la microbiota intestinal, planteándose la hipótesis de que los cambios de temperatura afectan a la microbiota de insectos ectotermos. Para ello se seleccionaron dos grupos de grillos en cajas separadas y se les sometió a temperaturas de 20 ºC y 30 ºC respectivamente. Posteriormente se les extrajo el intestino y se cuantificaron sus poblaciones bacterianas mediante técnicas metagenómicas. Los resultados obtenidos mostraron que los taxones más abundantes apenas variaron en todas las muestras. La abundancia relativa de bacterias perte-necientes al filo Firmicutes fue de 31,5 ± 2,06 %, en Bacteroidetes 24,25 ± 3,89 % y en Proteobacteria 44 ± 4,85 %. La única muestra que mostró diferencia fue la criada a 30ºC, en la que se detectó un 0,8% de Actinobacteria. Al cuantificar estas poblaciones se observó que la mayor parte de la microbiota en todas las muestras es similar a nivel taxonómico de filo y nivel de clase, excepto a la temperatura de 30 ºC en la que se detecta un pequeño porcentaje de Actinobacterias. En conclusión, se podría decir que la temperatura de cría de las granjas de grillos ha influido ligeramente en la composición de la microbiota intestinal, por lo que se acepta la hipótesis inicial.Se ha observado una alta mortalidad en la muestra mantenida a 30ºC, lo que sugiere que este factor debe ser cuidadosamente considerado en la cría masiva de grillos