Characterization of the mycorrhizal fungi of the orchids, cattleya quadricolor and masdevallia spp. native to the valle del cauca: biotechnology resources for the production and conservation of orchids of commercial interest.

The orchid family is a group of highly attractive plants renowned for their exotic and colorful flowers, of interest worldwide to horticulturists and plant collectors. Subsequently, many species are threatened with extinction in the wild, due to an over-reliance of orchid vendors on specimens collected from native habitats. The pressure from over-collection of wild specimens combines with those of general anthropogenic degradation of tropical ecosystems to make the Orchidaceae plant family a conservation priority worldwide. It is estimated that the Orchidaceae family contains more than 25000 species, with the majority of these native to tropical regions. In Colombia, close to 3500 species are known, distributed in 228 genera. Many Colombian species are recognized for their great ornamental potential, however despite the commercial interest, efficient protocols for orchid plant propagation are lacking in many cases. This is in large part a consequence of the intimate symbiotic interaction that all orchids have with mycorrhizal fungi, which provide essential nutrients for seed germination and plant establishment. Worldwide, only few groups of fungi are associated with orchid mycorrhizae: Tulasnella, Ceratobasidium and Sebacina are the most common. Very few studies have focused on the mycorrhizal interactions of tropical orchid species. In Colombia, the greatest floriculture interest focuses on the orchids of the genera Cattleya and Masdevallia spp. as these plants are difficult to cultivate from seed, much of the commercialization of these species relies on illegal extraction of plants from the wild. These species represent more than 50% of the Colombian orchid species threatened with extinction. For both conservation purposes, and to promote environmentally-responsible floriculture enterprises, it is desirable to develop protocols for the efficient propagation of these highly sought-after species. The use of in vitro tissue culture techniques has facilitated rapid propagation of orchids from clonal tissue. Nonetheless, efficiency is often dramatically reduced during the crucial step of transferring the plantlets from sterile media to general cultivation substrates (hardening). Furthermore, it is of interest to promote orchid propagation from seed in order to maintain the genetic diversity of artificial populations, to promote resistance to disease. Propagation from seed is also critical in programs for the reintroduction of populations to the wild. Orchid seeds are extremely small, lacking the endosperm store that usually provisions the embryo during the initial stages of germination. Instead, orchid seeds rely on colonization by mycorrhizal fungi to provide essential nutrients during the germination process. No studies exist of the mycorrhizal fungi associated naturally with Cattleya quadricolor and Masdevallia spp. from Colombia. The proposed research aims to rectify this situation, through the culture and identification, using morphological and molecular techniques, of the fungi present in mycorrhizal associations with these species native to the Valle del Cauca. additionally, we aim to evaluate the potential of the cultured fungi in symbiotic seed germination protocols, in order to generate technical protocols for the production and conservation of these orchids of high commercial interest in the Valle del Cauca department.