Spatial and Temporal Variation in Fungal Endophyte Communities Isolated from Cultivated Cotton (Gossypium hirsutum)

Abstract

Studies of fungi in upland cotton (Gossypium hirsutum) cultivated in the United States have largely focused on monitoring and controlling plant pathogens. Given increasing interest in asymptomatic fungal endophytes as potential biological control agents, surveys are needed to better characterize their diversity, distribution patterns and possible applications in integrated pest management. We sampled multiple varieties of cotton in Texas, USA and tested for temporal and spatial variation in fungal endophyte diversity and community composition, as well as for differences associated with organic and conventional farming practices. Fungal isolates were identified by morphological and DNA identification methods. We found members of the genera Alternaria, Colletotrichum and Phomopsis, previously isolated as endophytes from other plant species. Other recovered species such as Drechslerella dactyloides (formerly Arthrobotrys dactyloides) and Exserohilum rostratum have not, to our knowledge, been previously reported as endophytes in cotton. We also isolated many latent pathogens, but some species such as Alternaria tennuissima, Epicoccum nigrum, Acremonium alternatum, Cladosporium cladosporioides, Chaetomium globosum and Paecilomyces sp., are known to be antagonists against plant pathogens, insects and nematode pests. We found no differences in endophyte species richness or diversity among different cotton varieties, but did detect differences over time and in different plant tissues. No consistent patterns of community similarity associated with variety, region, farming practice, time of the season or tissue type were observed regardless of the ecological community similarity measurements used. Results indicated that local fungal endophyte communities may be affected by both time of the year and plant tissue, but the specific community composition varies across sites. In addition to providing insights into fungal endophyte community structure, our survey provides candidates for further evaluation as potential management tools against a variety of pests and diseases when present as endophytes in cotton and other plants.

Profundae diversitas: the uncharted genetic diversity in a newly studied group of fungal root endophytes

“…A recent study which sampled the endophyte diversity in the above-ground tissues of cotton from several populations found a very diverse group, but with relatively few Penicillium (Ek-Ramos et al 2013). Fungal diversity was also high in a review of the endophytes in grass species, with some assemblage similarity to ours (Sánchez Márquez et al 2012).…”

“…In recent years, DNA-based studies of endophytic organisms isolated from the wild and cultivated plant systems have led to an increasing level of awareness of the high phylogenetic diversity within fungal endophytes (Andrade-Linares et al 2011; Sánchez Márquez et al 2012; Ek-Ramos et al 2013). Some of these endophytes are localised to specific tissue types and some are found systemically.…”

Diversity and Communities of Foliar Endophytic Fungi from Different Agroecosystems of Coffea arabica L. in Two Regions of Veracruz, Mexico

“…Studies on the EFC of cultivable host plants have shown variability among these communities based on the regions in which the plants are cultivated [37], [38]; however, the variability in EFC among management systems is still poorly understood.…”

Endophytic fungi alter sucking bug responses to cotton reproductive structures

“…in Ek‐Ramos et al . () and subsequently misidentified as Purpureocillium lilacinum in Lopez et al . () and Lopez & Sword ().…”

“…Fungi associated with cotton have been most intensively studied in the context of mycorrhizal interactions and as pathogens (Nehl & McGee, ; Bell et al ., ). Published surveys explicitly aimed at characterizing fungal endophyte diversity in asymptomatic cotton exist, but are relatively rare (e.g., Australia: McGee, ; Wang et al ., ; the United States: Palmateer et al ., ; Ek‐Ramos et al ., ; and Brazil: de Souza Vieira et al ., ). Here we show that manipulating the presence of two strains of fungi that can colonize cotton as an endophyte, Phialemonium inflatum and Beauveria bassana , affects the host plant selection behavior of two key generalist hemipteran sucking bug pests, the western tarnished plant bug ( Lygus hesperus [Miridae] and the southern green stinkbug Nezara viridula [Pentatomidae]) under both no‐choice and choice conditions.…”