Agricultural Microbes Genome 2 Conference

Poster: Microbial Diversity
P02_02.html

THE UV LIGHT-INDUCED CONVERSION OF PESTALOTIOPSIS TO MONOCHAETIA AND TRUNCATELLA

¹ Department of Plant Sciences and Plant Pathology, AgBiosciences facility, Montana State University, Bozeman, MT 59717

² Department of Botany and Range Science, Brigham Young University, Provo, UT 84112

Pestalotiopsis microspora is one of the most commonly isolated endophytes associated with rainforest plants. It has been found in rainforest plant species located on every continent that supports rainforest growth. This endophytic fungus seems to play several important roles in both protecting its host plant and in recycling nutrients in the ecosystem. Frequently, other fungal genera are also isolated from these plants and they are Monochaetia sp., and Truncatella sp.. These fungi differ from P. microspora in that they have fewer or no appendages on their conidia, nevertheless, the number of cells in the conidia remains the same at five. UV irradiation of P. microspora spores which have appendages at both apices can result in a variety of spore types including those representative of Monochaetia sp. and Truncatella sp. The conidia of these UV mutants, do remain true to biological form by also producing spores in their acervuli that are identical to the spore types from which they were derived. Sequence analysis of the DNA of various isolates Pestalotiopsis microsporav by themselves revealed 1-5 % differences in the ITS regions and 5.8S r DNA. By the same token, and wild type isolates of M. camelliae revealed 2.58 % base sequence differences in the ITS regions and 5.8S rDNA. On the other hand, there was 100% sequence identity in both of these regions in the Monochaetia -like and Truncatella -like UV generated isolates obtained after irradiation of P. microspora cultures. From these studies it appears that the number of appendages in this group of fungi is not related to genes coded in the ITS or 5.8r DNA regions of the genome. It also appears that an examination of the phylogenetic tree, using ITS and 5.8S rDNA reveals that fungi in this group evolved from the same ancestor. Certainly, this conclusion is borne out by our ability to generate fungi of various taxonomically accepted genera by UV irradiation.