Limits...
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.

Show MeSH

Related in: MedlinePlus

E. nigrum and sugarcane-associated fungi re-isolation from the phylloplane of sugarcane grown in greenhouse.E.nigrum and sugarcane-associated fungi were re-isolated 20 and 60 days after inoculation of the P16 endophytic strain on leaves of sugarcane plants. The E. nigrum isolation frequency was compared with the total isolation frequency of sugarcane-associated fungi. Isolation frequency of the endophytic fungi from leaves (a) and sheaths (b) is shown in CFU per leaf/sheath fragment. Isolation frequency of epiphytic fungi (c) is shown in CFU per cm2 and includes abaxial and adaxial surfaces of the leaf fragments. All the data were transformed with √ x + 0.5 and submitted to analysis of variance followed by Tukey’s test. Means followed by the same letter indicate that they were not statistically different (Tukey’s test, P>5%). Control indicates the non-inoculated plants, while P16 indicates plants inoculated with the E. nigrum P16 strain.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3366970&req=5

pone-0036826-g001: E. nigrum and sugarcane-associated fungi re-isolation from the phylloplane of sugarcane grown in greenhouse.E.nigrum and sugarcane-associated fungi were re-isolated 20 and 60 days after inoculation of the P16 endophytic strain on leaves of sugarcane plants. The E. nigrum isolation frequency was compared with the total isolation frequency of sugarcane-associated fungi. Isolation frequency of the endophytic fungi from leaves (a) and sheaths (b) is shown in CFU per leaf/sheath fragment. Isolation frequency of epiphytic fungi (c) is shown in CFU per cm2 and includes abaxial and adaxial surfaces of the leaf fragments. All the data were transformed with √ x + 0.5 and submitted to analysis of variance followed by Tukey’s test. Means followed by the same letter indicate that they were not statistically different (Tukey’s test, P>5%). Control indicates the non-inoculated plants, while P16 indicates plants inoculated with the E. nigrum P16 strain.

Mentions: The isolation analysis of the disinfected sugarcane leaves and sheaths did not reveal significant differences in the number of E.nigrum CFUs recovered from these organs during the two sampling periods, as observed from the analysis of variance (Figure 1a and Figure 1b). E. nigrum was not isolated as an endophyte from the leaves and sheaths of the control plants in any sample period. In studying the effect of the inoculation with E. nigrum mycelia fragments on the endophytic fungal isolation frequency in these organs, the analysis also did not reveal differences in the number of CFUs recovered from the leaves over time (Figure 1a), but the number of CFUs recovered from the sheaths increased as the plant aged (Figure 1b). Most of the colonies obtained from the inoculated plants after disinfection were E. nigrum, which demonstrates the capacity of this fungus to endophytically colonize not only senescent leaves but also newly opened leaves on the sugarcane plants (not shown). These results also confirm previous reports on the sugarcane endophytic behavior of E. nigrum[21], [22] and indicate that E. nigrum is capable of disseminating to other tissues after the inoculation on leaves with mycelial fragments.


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

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

E. nigrum and sugarcane-associated fungi re-isolation from the phylloplane of sugarcane grown in greenhouse.E.nigrum and sugarcane-associated fungi were re-isolated 20 and 60 days after inoculation of the P16 endophytic strain on leaves of sugarcane plants. The E. nigrum isolation frequency was compared with the total isolation frequency of sugarcane-associated fungi. Isolation frequency of the endophytic fungi from leaves (a) and sheaths (b) is shown in CFU per leaf/sheath fragment. Isolation frequency of epiphytic fungi (c) is shown in CFU per cm2 and includes abaxial and adaxial surfaces of the leaf fragments. All the data were transformed with √ x + 0.5 and submitted to analysis of variance followed by Tukey’s test. Means followed by the same letter indicate that they were not statistically different (Tukey’s test, P>5%). Control indicates the non-inoculated plants, while P16 indicates plants inoculated with the E. nigrum P16 strain.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0036826-g001: E. nigrum and sugarcane-associated fungi re-isolation from the phylloplane of sugarcane grown in greenhouse.E.nigrum and sugarcane-associated fungi were re-isolated 20 and 60 days after inoculation of the P16 endophytic strain on leaves of sugarcane plants. The E. nigrum isolation frequency was compared with the total isolation frequency of sugarcane-associated fungi. Isolation frequency of the endophytic fungi from leaves (a) and sheaths (b) is shown in CFU per leaf/sheath fragment. Isolation frequency of epiphytic fungi (c) is shown in CFU per cm2 and includes abaxial and adaxial surfaces of the leaf fragments. All the data were transformed with √ x + 0.5 and submitted to analysis of variance followed by Tukey’s test. Means followed by the same letter indicate that they were not statistically different (Tukey’s test, P>5%). Control indicates the non-inoculated plants, while P16 indicates plants inoculated with the E. nigrum P16 strain.
Mentions: The isolation analysis of the disinfected sugarcane leaves and sheaths did not reveal significant differences in the number of E.nigrum CFUs recovered from these organs during the two sampling periods, as observed from the analysis of variance (Figure 1a and Figure 1b). E. nigrum was not isolated as an endophyte from the leaves and sheaths of the control plants in any sample period. In studying the effect of the inoculation with E. nigrum mycelia fragments on the endophytic fungal isolation frequency in these organs, the analysis also did not reveal differences in the number of CFUs recovered from the leaves over time (Figure 1a), but the number of CFUs recovered from the sheaths increased as the plant aged (Figure 1b). Most of the colonies obtained from the inoculated plants after disinfection were E. nigrum, which demonstrates the capacity of this fungus to endophytically colonize not only senescent leaves but also newly opened leaves on the sugarcane plants (not shown). These results also confirm previous reports on the sugarcane endophytic behavior of E. nigrum[21], [22] and indicate that E. nigrum is capable of disseminating to other tissues after the inoculation on leaves with mycelial fragments.

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