RESUMO
To examine the effects of water stress and Cenangium ferruginosum (CF) on the fungal endophytic community of needles of Pinus koraiensis (PK), fungal endophytes isolated from the needles of 5-year-old PK seedlings were compared before and after exposure to water stress conditions and artificial inoculation with CF ascospores. Artificial CF inoculation was successfully confirmed using PCR with CF-specific primers (CfF and CfR). For comparison of the degree of water deficit in water-stressed and control groups of PK seedlings infected with CF, the water saturation deficit and water potential were measured. Lower water potential estimates were found in the water-stressed seedlings than in the control group. The fungal endophytes isolated from the second-year needles of non-water-stressed seedlings before and after CF inoculation revealed that primary saprobes were approximately 30% and 71.7%, respectively, and the remaining endophytes were rot fungi or pathogens. Sixty days after CF inoculation, diverse fungal endophytes in the first-year needles were isolated from the water-stressed seedlings. However, some fungal endophytes isolated from the non-water-stressed seedlings were also identified. Fungal endophytes in the second-year needles of the water-stressed and non-water-stressed seedlings were approximately 8% and 71.7% of saprobes, respectively, and the remaining endophytes were rot fungi or pathogens. On the basis of the results, we conclude that water deficit and CF can have an effect on fungal endophytic communities in the needles of PK seedlings.
Assuntos
Pré-Escolar , Humanos , Desidratação , Endófitos , Fungos , Agulhas , Pinus , Reação em Cadeia da Polimerase , PlântulaRESUMO
El uso desmedido de fertilizantes químicos nitrogenados y pesticidas ha traído graves consecuencias ambientales, por lo que se ha prestado gran atención al estudio de la microbiota nativa de los cultivos y sus beneficios a la planta, incluyendo la caña de azúcar. Este trabajo se realizó con el objetivo de caracterizar la microbiota nativa de la caña de azúcar. Se utilizaron 5 cepas bacterianas y 50 aislados provenientes del interior de este cultivo. Se determinó la actividad nitrogenasa y la influencia de la fuente de carbono, nitrógeno y el pH en la misma, mediante cromatografía gaseosa. Se detectó la producción de ácido indolacético por Dot-Immunobinding y el método de Salkowski. Del total de cepas y aislados, 19 mostraron actividad nitrogenasa, con valores entre 100 y 5000 //g/mL, y 6, Gluconacetobacter diazotrophicus PAl-5, Gluconacetobacter diazotrophicus 1-05, Gluconacetobacter diazotrophicus 4-02, aislado 17, aislado 30 y aislado 305; además, tienen la capacidad de producir AIA (valores entre 1,7 y 2,5 JMg/mL). Se demostró que las fuentes nutricionales y el pH del medio de cultivo influyen sobre la actividad nitrogenasa de las cepas representativas de la comunidad endófita.
Excessive application of chemical nitrogen fertilisers and pesticides has badly affected the environment. This has led to great interest being shown in studying a crops native microbial community and its benefit for plants. This paper was thus aimed at characterising sugarcanes endophytic microbial community. 5 sugar cane strains and 50 isolates were used. Gas chromatography was used for measuring nitrogenase activity and the influence of carbon and nitrogen sources and pH on cultures. Indol acetic (IAA) production was detected by Dot-Immunobinding and Salkowskis method. These results show that 19 strains and isolates had nitrogenase activity, values ranging from 100 to 5000 /zg/mL; 6 of them produced IAA (values ranging from 1,7 to 2,5 //g/mL): Gluconacetobacter iazotrophicus PAl-5, Gluconacetobacter diazotrophicus 1-05, Gluconacetobacter diazotrophicus 4-02, 17, 30 and 305. It was demonstrated that culture medium nutrient sources and pH affectedthe nitrogenase activity of the strains representing the endophytic community.