Endorhizal Fungal Association and Colonization Patterns in Solanaceae

The Solanaceae family includes plants of high economic and medicinal value. Information on endorhizal associations in Solanaceae is limited. We investigated arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal associations in 20 solanaceous plant species (7 genera) taken from one or more sites, measuring the percentage of root length colonized in plants having different AM and DSE fungal structures. Root samples of all the plant species examined had AM fungal structures, and DSE fungal colonization was found in 80% of the plant species. Total AM and DSE fungal colonization and root length of plants with different fungal structures varied significantly between species. Significant between-site variation was found for root length in plants with fungal structures in Lycopersicon esculentum Mill., Capsicum annuum L., Datura metel L., Solanum melongena L., S. nigrum L., S. trilobatum L. and S. torvum SW. AM morphology was predominantly intermediate-type (60%), followed by Paris-type (30%). Solanum melongena and S. nigrum at different sites had Paris-type or intermediate AM morphology. DSE fungal colonization also exhibited significant between-site variation in Capsicum frutescens, C. annum, Datura metel, Solanum melongena, S. trilobatum and S. nigrum. We found a significant negative correlation between AM and DSE fungal colonization.

Arbuscular Mycorrhizal and Dark Septate Endophyte Fungal Associations in South Indian Aquatic and Wetland Macrophytes

Investigations on the prevalence of arbuscular mycorrhizal (AM) and dark septate endophyte (DSE) fungal symbioses are limited for plants growing in tropical aquatic and wetland habitats compared to those growing on terrestrial moist or dry habitats. Therefore, we assessed the incidence of AM and DSE symbiosis in 8 hydrophytes and 50 wetland plants from four sites in south India. Of the 58 plant species examined, we found AM and DSE fungal symbiosis in 21 and five species, respectively. We reported for the first time AM and DSE fungal symbiosis in seven and five species, respectively. Intermediate-type AM morphology was common, and AM morphology is reported for the first time in 16 plant species. Both AM and DSE fungal colonization varied significantly across plant species and sites. Intact and identifiable AM fungal spores occurred in root zones of nine plant species, but AM fungal species richness was low. Though no clear relationship between AM and DSE fungal colonization was recognized, a significant negative correlation between AM colonization and spore numbers was established. Our study suggests that the occurrence of AM and DSE fungal symbiosis in plants growing in hydrophytic and wetland habitats is not as common as in terrestrial habitats.

Fungal associations in gametophytes and young sporophytic roots of the fern Nephrolepis exaltata

Fungal associations in gametophytes and young sporophytic roots of the fernNephrolepis exaltataInformation is limited on the presence of endophytic fungal associations in green gametophytes and young sporophytes of extant ferns. Nothing is known about their presence in Polypodiales, the largest order among extant ferns. We screened chlorophyllous gametophytes and young sporophytes ofNephrolepis exaltata(L.) Schott., (Lomariopsidaceae, Polypodiales) growing naturally on soil, brick and coir for the presence of fungal endophytes. Gametophytes and young sporophytes growing on different substrates were invariably colonized by septate endophytic fungi. Hyaline or brown, regularly septate, inter- or intracellular hyphae with moniliform cells or microsclerotia characterized septate endophytic fungi. However, only the roots of young sporophytes growing on soil and bricks harboured arbuscular mycorrhizal (AM) fungi. The AM morphology conformed to the intermediate type with intracellular hyphal coils, arbusculate coils and intercellular hyphae. No AM fungal spores could be retrieved from the soil on which gametophytes and young sporophytes were growing. The observations in this study support the idea that the septate fungal endophytes could confer an ecological advantage on colonized individuals, especially on nutrient deficient substrates.