Antagonistic interaction between Trichoderma asperellum and Phytophthora capsici in vitro

Abstract

Phytophthora capsici is a phytopathogen that causes a destructive pepper blight that is extremely difficult to control. Using a fungicide application against the disease is costly and relatively ineffective and there is also a huge environmental concern about the use of such chemicals. The genus Trichoderma has been known to have a potential biocontrol issue. In this paper we investigate the mechanism for causing the infection of T. asperellum against P. capsici. Trichoderma sp. (isolate CGMCC 6422) was developed to have a strong antagonistic action against hyphae of P. capsici through screening tests. The strain was identified as T. asperellum through using a combination of morphological characteristics and molecular data. T. asperellum was able to collapse the mycelium of the colonies of the pathogen through dual culture tests by breaking down the pathogenic hyphae into fragments. The scanning electron microscope showed that the hyphae of T. asperellum surrounded and penetrated the pathogens hyphae, resulting in hyphal collapse. The results show that seven days after inoculation, the hyphae of the pathogen were completely degraded in a dual culture. T. asperellum was also able to enter the P. capsici oospores through using oogonia and then developed hyphae and produced conidia, leading to the disintegration of the oogonia and oospores. Seven days after inoculation, an average 10.8% of the oospores were infected, but at this stage, the structures of oospores were still intact. Subsequently, the number of infected oospores increased and the oospores started to collapse. Forty-two days after inoculation, almost all the oospores were infected, with 9.3% of the structures of the oospores being intact and 90.7% of the oospores having collapsed.

Genetic diversity and biocontrol efficacy of indigenous Trichoderma isolates against Fusarium wilt of pepper

“…is important to verify morphological characterization, since use of morphological identification only had misleading results . Recently, molecular identification based on ITS sequencing has been highly trusted upon . Molecular markers were proved to be excellent approaches to diversity for studying genetic relationships .…”

A Real-Time PCR Assay for the Quantification of Plasmopara viticola Oospores in Grapevine Leaves

“…For instance, exposure to high temperatures (40 to 53°C) for 1 to 24 h resulted in the death of oospores of Phytophthora capsici (Etxeberria et al, 2011) and the inhibition of the germination of oospores of P. kernoviae and P. infestans (Fay and Fry, 1997;Widmer, 2011). Trichoderma asperellum, a common soil-borne fungus, can penetrate oospores of P. capsici, develop hyphae, and produce conidia leading to the disintegration of oospores (Jiang et al, 2016). Other microorganisms, including the biocontrol agents Bacillus subtilis and Trichoderma hartianum T39, can prevent the germination of Plasmopara viticola oospores (Vecchione et al, 2005;Dagostin et al, 2006).…”

Molecular tagging of biocontrol fungus Trichoderma asperellum and its colonization in soil

“…Additionally, in order to effectively overcome the interference of the indigenous micro‐organisms with the natural environment, the double marking method is commonly applied, such as the double markers of antimicrobial resistance and green fluorescent protein (GFP), to avoid measuring the effects of naturally antimicrobial‐resistant or fluorescent micro‐organisms (McDougal et al ; Hohmann et al ). Trichoderma asperellum possesses strong antagonistic effects on a number of soil‐borne micro‐organisms such as R. solani , Fusarium sp., Botryosphaeria berengeriana and Colletotrichum gloeosporioides (Krishna et al ; Mahmoud et al ; Jiang et al ; Wu et al ). Its biocontrol effects are of significance, however, to date, there have been no reports about the studies on double molecular tags and its colonization in soil.…”