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Epicoccum nigrum P16, a sugarcane endophyte, produces antifungal compounds and induces root growth.

Fávaro LC, Sebastianes FL, Araújo WL - PLoS ONE (2012)

Bottom Line: We report an approach based on inoculation followed by re-isolation, molecular monitoring, microscopic analysis, plant growth responses to fungal colonization, and antimicrobial activity tests to study the basic aspects of the E. nigrum endophytic interaction with sugarcane, and the effects of colonization on plant physiology.The results indicate that E. nigrum was capable of increasing the root system biomass and producing compounds that inhibit the in vitro growth of sugarcane pathogens Fusarium verticillioides, Colletotrichum falcatum, Ceratocystis paradoxa, and Xanthomomas albilineans.In addition, this work contributes to the knowledge of the interaction of this ubiquitous endophyte with the host plant, and also to a better use of microbial endophytes in agriculture.

View Article: PubMed Central - PubMed

Affiliation: Brazilian Agricultural Research Corporation, Embrapa Agroenergia, Brasília, Distrito Federal, Brazil. leia.favaro@embrapa.br

ABSTRACT

Background: Sugarcane is one of the most important crops in Brazil, mainly because of its use in biofuel production. Recent studies have sought to determine the role of sugarcane endophytic microbial diversity in microorganism-plant interactions, and their biotechnological potential. Epicoccum nigrum is an important sugarcane endophytic fungus that has been associated with the biological control of phytopathogens, and the production of secondary metabolites. In spite of several studies carried out to define the better conditions to use E. nigrum in different crops, little is known about the establishment of an endophytic interaction, and its potential effects on plant physiology.

Methodology/principal findings: We report an approach based on inoculation followed by re-isolation, molecular monitoring, microscopic analysis, plant growth responses to fungal colonization, and antimicrobial activity tests to study the basic aspects of the E. nigrum endophytic interaction with sugarcane, and the effects of colonization on plant physiology. The results indicate that E. nigrum was capable of increasing the root system biomass and producing compounds that inhibit the in vitro growth of sugarcane pathogens Fusarium verticillioides, Colletotrichum falcatum, Ceratocystis paradoxa, and Xanthomomas albilineans. In addition, E. nigrum preferentially colonizes the sugarcane surface and, occasionally, the endophytic environment.

Conclusions/significance: Our work demonstrates that E. nigrum has great potential for sugarcane crop application because it is capable of increasing the root system biomass and controlling pathogens. The study of the basic aspects of the interaction of E. nigrum with sugarcane demonstrated the facultative endophytism of E. nigrum and its preference for the phylloplane environment, which should be considered in future studies of biocontrol using this species. In addition, this work contributes to the knowledge of the interaction of this ubiquitous endophyte with the host plant, and also to a better use of microbial endophytes in agriculture.

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E. nigrum conidia germination on sugarcane leaf fragments analyzed by scanning electronic microscopy.Scanning electronic microscopy analysis of the conidia germination of the E. nigrum P16 endophytic strain on sugarcane leaf fragments. (a–b) After 12 hours of incubation in wet chamber it was possible to visualize the conidia germination and hyphae next to the stomata (1000X and 2000X, respectively). (c) After 40 hours of incubation it was possible to visualize hyphal ramification and random surface colonization (1000X). (d) After 64 hours, the leaf surface was completely covered with E. nigrum hyphae (1000X).
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pone-0036826-g003: E. nigrum conidia germination on sugarcane leaf fragments analyzed by scanning electronic microscopy.Scanning electronic microscopy analysis of the conidia germination of the E. nigrum P16 endophytic strain on sugarcane leaf fragments. (a–b) After 12 hours of incubation in wet chamber it was possible to visualize the conidia germination and hyphae next to the stomata (1000X and 2000X, respectively). (c) After 40 hours of incubation it was possible to visualize hyphal ramification and random surface colonization (1000X). (d) After 64 hours, the leaf surface was completely covered with E. nigrum hyphae (1000X).

Mentions: The germination of E. nigrum conidia on sugarcane leaf fragments was investigated by scanning electronic microscopy (SEM), which showed that conidia germination occurred at 12–16 hours after inoculation and that the hyphae penetrated the leaf tissue through the stomata (Figure 3). No changes associated with the direct penetration of the surface, such as the development of structures similar to the appressorium or changes on the leaf surface to which the conidia and hyphae were attached, were observed. Random hyphal ramification was observed 40 hours after surface colonization, and the hypha seems to firmly adhere to the cuticle (Figure 3). After 64 hours, the leaf surface was completely covered with E. nigrum hyphae (Figure 3).


Epicoccum nigrum P16, a sugarcane endophyte, produces antifungal compounds and induces root growth.

Fávaro LC, Sebastianes FL, Araújo WL - PLoS ONE (2012)

E. nigrum conidia germination on sugarcane leaf fragments analyzed by scanning electronic microscopy.Scanning electronic microscopy analysis of the conidia germination of the E. nigrum P16 endophytic strain on sugarcane leaf fragments. (a–b) After 12 hours of incubation in wet chamber it was possible to visualize the conidia germination and hyphae next to the stomata (1000X and 2000X, respectively). (c) After 40 hours of incubation it was possible to visualize hyphal ramification and random surface colonization (1000X). (d) After 64 hours, the leaf surface was completely covered with E. nigrum hyphae (1000X).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3366970&req=5

pone-0036826-g003: E. nigrum conidia germination on sugarcane leaf fragments analyzed by scanning electronic microscopy.Scanning electronic microscopy analysis of the conidia germination of the E. nigrum P16 endophytic strain on sugarcane leaf fragments. (a–b) After 12 hours of incubation in wet chamber it was possible to visualize the conidia germination and hyphae next to the stomata (1000X and 2000X, respectively). (c) After 40 hours of incubation it was possible to visualize hyphal ramification and random surface colonization (1000X). (d) After 64 hours, the leaf surface was completely covered with E. nigrum hyphae (1000X).
Mentions: The germination of E. nigrum conidia on sugarcane leaf fragments was investigated by scanning electronic microscopy (SEM), which showed that conidia germination occurred at 12–16 hours after inoculation and that the hyphae penetrated the leaf tissue through the stomata (Figure 3). No changes associated with the direct penetration of the surface, such as the development of structures similar to the appressorium or changes on the leaf surface to which the conidia and hyphae were attached, were observed. Random hyphal ramification was observed 40 hours after surface colonization, and the hypha seems to firmly adhere to the cuticle (Figure 3). After 64 hours, the leaf surface was completely covered with E. nigrum hyphae (Figure 3).

Bottom Line: We report an approach based on inoculation followed by re-isolation, molecular monitoring, microscopic analysis, plant growth responses to fungal colonization, and antimicrobial activity tests to study the basic aspects of the E. nigrum endophytic interaction with sugarcane, and the effects of colonization on plant physiology.The results indicate that E. nigrum was capable of increasing the root system biomass and producing compounds that inhibit the in vitro growth of sugarcane pathogens Fusarium verticillioides, Colletotrichum falcatum, Ceratocystis paradoxa, and Xanthomomas albilineans.In addition, this work contributes to the knowledge of the interaction of this ubiquitous endophyte with the host plant, and also to a better use of microbial endophytes in agriculture.

View Article: PubMed Central - PubMed

Affiliation: Brazilian Agricultural Research Corporation, Embrapa Agroenergia, Brasília, Distrito Federal, Brazil. leia.favaro@embrapa.br

ABSTRACT

Background: Sugarcane is one of the most important crops in Brazil, mainly because of its use in biofuel production. Recent studies have sought to determine the role of sugarcane endophytic microbial diversity in microorganism-plant interactions, and their biotechnological potential. Epicoccum nigrum is an important sugarcane endophytic fungus that has been associated with the biological control of phytopathogens, and the production of secondary metabolites. In spite of several studies carried out to define the better conditions to use E. nigrum in different crops, little is known about the establishment of an endophytic interaction, and its potential effects on plant physiology.

Methodology/principal findings: We report an approach based on inoculation followed by re-isolation, molecular monitoring, microscopic analysis, plant growth responses to fungal colonization, and antimicrobial activity tests to study the basic aspects of the E. nigrum endophytic interaction with sugarcane, and the effects of colonization on plant physiology. The results indicate that E. nigrum was capable of increasing the root system biomass and producing compounds that inhibit the in vitro growth of sugarcane pathogens Fusarium verticillioides, Colletotrichum falcatum, Ceratocystis paradoxa, and Xanthomomas albilineans. In addition, E. nigrum preferentially colonizes the sugarcane surface and, occasionally, the endophytic environment.

Conclusions/significance: Our work demonstrates that E. nigrum has great potential for sugarcane crop application because it is capable of increasing the root system biomass and controlling pathogens. The study of the basic aspects of the interaction of E. nigrum with sugarcane demonstrated the facultative endophytism of E. nigrum and its preference for the phylloplane environment, which should be considered in future studies of biocontrol using this species. In addition, this work contributes to the knowledge of the interaction of this ubiquitous endophyte with the host plant, and also to a better use of microbial endophytes in agriculture.

Show MeSH
Related in: MedlinePlus