Planta Med 2011; 77 - PL49
DOI: 10.1055/s-0031-1282698

Screening methods to determine potential bioactivity of endophytic fungi from Vitis vinifera

KM Valant Vetschera 1, C Zahradnik 1
  • 1Department of Systematic and Evolutionary Botany, University of Vienna, Austria

Fungal endophytes are widespread in plants and colonize living internal tissue of their hosts symptomlessly [1]. They are well known for their beneficial effects for their hosts, providing increased tolerance against abiotic and biotic stresses, enhancing inter alia resistance to insect pests and fungal or microbial infection. This is largely due to their production of bioactive secondary metabolites [2]. Recently, Zingiberaceae species were studied and several bioassays successfully developed to test for antifungal activities [3]. These tests were now applied to the analysis of Vitis plants and their endophytic fungi, including routinely: a) competition tests against Cladosporium sphaerospermum, to investigate the dominance of the endophyte compared to its competitor in vitro [4]; b) thin layer bio-autography with the crude endophytic extract and subsequent determination of inhibition halos, caused by separated compounds after spraying with conidiospores of C. sphaerospermum; c) establishing species-specificity by cultivation of the endophytic fungus on media containing the crude extract of the respective plant; d) performing a modified ELISA-test with the fungal crude extract to determine the median effective concentration (EC50) for inhibition of the growth of C. sphaeospermum. Several fungal endophytes have so far been isolated from Vitis vinifera L. cultivars, and respective results will be presented. The methods described provide tools not only for testing for antifungal activities, but also for subsequent isolation of bioactive compounds, and eventually for their practical applications in pest control.

Acknowledgement: The financial support of „Society for the Advancement of Plant Sciences“ is gratefully acknowledged.

References: 1. Petrini O (1991) Microbial Ecology of Leaves, Springer Verlag, New York.

2. Gao F et al. (2010) Afr J Microbiol Res 4(13): 1346–1351.

3. Zahradnik C (2010) Pilzendophyten aus Alpinia malaccensis und Curcuma sp.: Kultur, Sekundärstoffprofil und Bioaktivität. Diploma thesis, Univ. of Vienna.

4. Yuen TK (1999) Microb Ecol 37: 257–262.