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Endophytic colonization of tomato plants by the biological control agent Clonostachys rosea

Publication: ResearchConference abstract for conference

Anna Kaja Høyer, Hans Jørgen Lyngs Jørgensen, Daniel Buchvaldt Amby, Birgit Jensen

Fungal endophytes live naturally inside plants without causing symptoms. On the contrary, they can promote plant growth and increase tolerance to abiotic and biotic stress. These beneficial effects have increased the agricultural interest for exploitation of fungal isolates with an endophytic life-style.
Clonostachys rosea occurs naturally world-wide and is capable of colonizing many different habitats. The fungus is primarily known as a versatile biological control agent. However, it has also been reported as a plant endophyte in, e.g., soybean, red clover and cacao. The C. rosea isolate IK726 efficiently controls seed- and soil-borne diseases and can furthermore promote plant growth. However, it is not known whether IK726 can colonize plants internally and therefore, the objective of the present study was to examine the possibility of an endophytic life-style of IK726 in tomato.
Tomato seeds were sown in vermiculite or soil and grown at 24°C in a growth chamber. After two weeks, conidial suspensions of IK726 were applied to the roots either by root dipping or soil drenching around the stem and plants were subsequently incubated for at least two weeks before sampling for re-isolation of C. rosea. Stems were surface disinfected by dipping in ethanol followed by flaming and sections (0.5-14 cm from the soil surface) were placed on potato dextrose agar plates with Novobiocin and incubated at 25°C. Fungi growing from the stem pieces were identified by microscopy. Isolation of C. rosea was successful from two to five weeks after IK726 inoculation, from plants grown in both soil and vermiculite and from both root dip and drench inoculated plants. Verticillium, Penicillium, Cladosporium, Fusarium and Trichoderma were furthermore isolated from stems of soil grown plants. Surface disinfection of roots eradicated all culturable fungi. Therefore, root parts were washed only in water before incubation on the isolation medium and this revealed >50% colonization of the roots sections with C. rosea, irrespective of the inoculation method.
In conclusion, we have shown for the first time that C. rosea can live as an endophyte in tomato stems and our results suggest that the endophytic colonization is systemic with the fungus growing from the roots and into the stem. Currently, we investigate if soil drenching with C. rosea IK726 can induce resistance against tomato diseases.
Original languageEnglish
Publication date15 Jun 2014
Number of pages1
StatePublished - 15 Jun 2014
Event - Uppsala, Sweden

Conference

ConferenceBiological control of fungal and bacterial plant pathogens:
NumberXIII
LocationCBC, Centre for Biological Control. SLU, Swedish University of Agricultural Sciences
CountrySweden
CityUppsala
Period15/06/201418/06/2014

ID: 118374985