Biodiversity and phylogeny of novel Trichoderma isolates from mangrove sediments and potential of biocontrol against Fusarium strains

Abstract

Background: Studies carried out with novel 13 strains of Trichoderma, isolated from mangrove sediments (PE, Brazil) using morphophysiological and molecular characterization, followed evaluation of biocontrol using Fusarium strains isolated from Caatinga soil (PE, Brazil). Trichoderma strains were characterized by polyphasic taxonomic approach, and the extracted DNA was amplified with primers ITS 1 and 4, and sequenced. The biocontrol evaluation was conducted at 24 and 48 h of growth intervals by Tukey test, with a significance of 5%. Antibiosis tests were assessed in vitro by dual plate and partition plate techniques against Fusarium strains.

Results: Trichoderma molecular identification, sequences of 500 bp were amplified, deposited into GenBank, and used for phylogenetic analyses. The strains were identified as T. asperellum (10), as T. harzianum (2) and one as T. longibrachiatum. Growth rate presented an average of 0.1207 cm h^-1 for Trichoderma and lower growth rate of 0.031 cm h^-1 for Fusarium spp., respectively. Antibiosis tests presented the best antagonist level of efficiency for T. asperellum UCP 0149 against F. solani UCP 1395 (82.2%) and F. solani UCP 1075 (70.0%), followed by T. asperellum UCP 0319 against F. solani UCP1083 (73.4%) and T. asperellum UCP 0168 against F. solani UCP1098 (71.5%), respectively.

Conclusions: The data obtained in this study as tool for identification of novel Trichoderma strains serve as basis for development of several sustainable use for biotechnological processes. Those Trichoderma strains found promising for the management antagonistic potential and interaction could aid the conduct of biotechnological biocontrol of contaminants, and improve environmental conditions for the health of plants.

Keywords: Biocontrol; Filamentous fungi; Molecular identification.

Fig. 1

Characterization of Trichoderma strains by macroscopic morphology of the growth pattern of colonies in PDA medium after 5 days: a Optical microscopy arrangements of hyphae; b Conidiophores and conidia. Magnification ×400

Fig. 2

PCR amplification on 1.5% agarose gel with products obtained from the regions of ITS primers of Trichoderma isolates which have distinct lineage strains. Trichoderma isolates as mentioned in Table 1

Fig. 3

Phylogenetic analysis of maximum likelihood tree was constructed by 602 bp aligned with partial sequences of the Internal transcribed spacer—ITS (ITS1, 5.8 S and ITS2), with 19 taxa belonging to the Trichoderma species, compatible with the isolates examined in this research

Fig. 4

Antagonistic effect through mycoparasitism by the overlapping of colonies (a) and by formation of inhibition halo (b, c) of Trichoderma spp. colonies inhibiting the growth of Fusarium spp. strains in direct confrontation in vitro. Isolates F. oxysporum UCP 1396 and F. solani UCP 1074 under effect of T. asperellum UCP 0319 (a, b). Isolates F. solani UCP 1395 under effect of T. asperellum UCP 0314 (c)

Fig. 5

Antagonistic effect through mycoparasitism due to the overlapping of colonies (a) and due to the formation of inhibition halos (b, c) of Trichoderma spp. Colonies, thus inhibiting the growth of Fusarium spp. strains in direct confrontation in vitro. Isolates F. oxysporium UCP 1396 and F. solani UCP 1074 under effect of T. asperellum UCP 0319 (a, b). Isolates F. solani UCP 1395 under effect of T. asperellum UCP 0314 (c)