Sebacina vermifera ssp. bescii v1.0
Sebacina vermifera
Sebacina vermifera ssp bescii colony in MMN agar. Photo Credit: Prasun Ray and Kelly D Craven at Samuel Noble Foundation.
Sebacina vermifera
Visualization of monilioid hyphae stained with WGA-AF® 488. Photo Credit: Prasun Ray and Kelly D Craven at Samuel Noble Foundation.
Sebacina vermifera
Transverse section of colonized switchgrass (Panicum virgatum L) root cells stained with WGA-AF® 488 and Propidium iodide by fluorescent microscopy. Photo Credit: Prasun Ray and Kelly D Craven at Samuel Noble Foundation.

Sebacinales belong to a taxonomically, ecologically, and physiologically diverse group of fungi in the Basidiomycota. While historically recognized as orchid mycorrhizae, recent DNA studies have brought to light both their pandemic distribution and the broad spectrum of mycorrhizal types they form (Oberwinkler et al., 2013). Indeed, ecological studies using molecular-based methods of detection have found Sebacinales fungi in field specimens of bryophytes (moss), pteridophytes (fern) and all families of herbaceous angiosperms (flowering plants) from temperate, subtropical and tropical regions. These natural host plants include, among others, liverworts, wheat, maize and Arabidopsis thaliana, the genetic model plant traditionally viewed as non-mycorrhizal (DeMars and Boerner 1996).

The orchid mycorrhizal fungus Sebacina vermifera (MAFF 305830) was first isolated from the Australian orchid Cyrtostylis reniformis (Warcup J 1988). Research performed with this strain clearly indicates its plant growth promoting abilities in a variety of plants (e.g. Ghimire et al., 2009; Waller et al., 2008), demonstrating little or no host specificity. Considering their proven beneficial impact on plant growth and their apparent ubiquity, Sebacinales fungi should be considered as a previously hidden, but amenable and effective microbial tool for enhancing plant productivity and stress tolerance. However, research performed thus far towards understanding the biology and potentially agronomic utility of Sebacinales fungi all involved strains isolated from orchids.

Hence full genome sequencing of this new strain of Sebacina vermifera (currently defined taxonomically as ssp. bescii) isolated from switchgrass (Panicum virgatum L.), the first such strain from any North American plant, will provide insight into the phylogeography, genetic and physiological diversity, and the variety of mechanisms employed by these fungi for mycorrhizal symbiosis and crop improvement not only in switchgrass but also other agronomically important crops.

Reference

DeMars B, Boerner R (1996) Vesicular arbuscular mycorrhizal development in the Brassicaceae in relation to plant life span Flora 191 (2) 179-189

Ghimire SR, Charlton ND, Craven KD (2009) The mycorrhizal fungus, Sebacina vermifera, enhances seed germination and biomass production in switchgrass (Panicum virgatum L). BioEnergy research 2 (1-2):51-58

Oberwinkler F, Riess K, Bauer R, Selosse M-A, Weiß M, Garnica S, Zuccaro A (2013) Enigmatic sebacinales Mycological Progress 12:1-27

Waller, F., Mukherjee, K., Deshmukh, S. D., Achatz, B., Sharma, M., Schäfer, P., & Kogel, K. H. (2008). Systemic and local modulation of plant responses by Piriformospora indica and related Sebacinales species. Journal of plant physiology, 165(1), 60-70.

Warcup J (1988) Mycorrhizal associations of isolates of Sebacina vermifera. New Phytologist 110 (2):227-231