Morphological and molecular identification of Fusarium spp. and Colletotrichum spp. isolated from infected vanilla orchid

Abstract

This study aimed to isolate and identify fungi involved in causing diseases to Vanilla planifolia as well as to study their pathogenicity level in causing disease. Methodology and results: The diseased parts of vanilla plants were collected from vanilla farms located in Pahang and Sabah, Malaysia from May 2015 to May 2016. Diseases tissue transplantation was adopted to isolate the fungi for morphology identification prior to the polymerase chain reaction (PCR) amplification of internal transcribed spacer (ITS) regions using universal primers for fungi, ITS1 and ITS4. After being isolated, the fungi pathogenicity was tested on detached fresh and mature vanilla leaves. A total of 22 fungal isolates were identified, Fusarium fujikuroi and F. oxysporum were the two most recovered species, followed by Colletotrichum gloeosporioides, Fusarium sp., F. proliferatum and F. solani. Pathogenicity test revealed a significantly high pathogenicity of F. oxysporum and C. gloeosporiodes (p<0.01) on detached vanilla leaf, with high level of damage. Conclusion, significance and impact of study: This study provides valuable information on fungi-associated diseases on vanilla plants grown in Malaysia and can be used for future development in disease management.