Ligniera
Although the genus Ligniera remains a valid genus, molecular evidence has led to what was previously known as L. verrucosa to be reclassified as Pseudoligniera verrucosa (Maire and Tison) Neuhauser, Hittorf, Kirchmair ( Hittorf et al 2020 ). What is referred to in the following personal comments as L. verrucosa is the organism that is now named Pseudoligniera verrucosa .
Personal Comments
I was interested in karyotyping Ligniera because of its similarity to Polymyxa . We had easy access to L. verrucosa on the Ohio University campus, but I held off with my karyological study because I knew some of Charles Miller's students were working on the ultrastructure of general development of L. verrucosa . Once their paper was accepted for publication, however, I felt free to take a walk around campus and pull up some Veronica in an area where I knew it would be infected with L. verrucosa . Since stages of development of Sorosphaera veronicae also could be in roots of Veronica , I spent hours sifting through fresh material with compound light microscopy to select only sections of roots that had sporogenic stages of Ligniera .
Transitional sporogenic plasmodia were easy to locate with techniques described in Meiosis & Karyotyping : I would cut a 1/2 µm "thick" section and examine it with light microscopy. When I found a transitional plasmodium, I would trim the block down to it and make serial sections for electron microscopy.
Images of Pseudoligniera
Selected References for Ligniera & Pseudoligniera
- Barr, D. J. S. 1979. Morphology and host range of Polymyxa graminis, Polymyxa betae, and Ligniera pilorum from Ontario and some other areas. Can. J. Plant Path. 1: 85-94.
- Braselton, J. P. 1989. Karyotypic analysis of Ligniera verrucosa (Plasmodiophoromycetes). Can. J. Bot. 67: 1216-1218.
- Cook, W. R. I. 1926. The genus Ligniera Maire and Tison. Trans. British Mycol. Soc. 11: 196-213.
- Hittorf, M. et al (2020). Revised taxonomy and expanded biodiversity of the Phytomyxea (Rhizaria, Endomyxa). J. Eukaryot. Microbiol. Doi: 10.1111/jeu.12817
- Maire, R. & A. Tison. 1911. Nouvelles recherches sur les Plasmodiophoracees. Ann. Mycol. 9: 226-246.
- Miller, C. E. 1959. Studies on the life cycle and taxonomy of Ligniera verrucosa . Amer. J. Bot. 46: 725-729.
- _____, R. W. Martin, & D. P. Dylewski. 1985. The ultrastructure of plasmodia, sporangia, and cystosori of Ligniera verrucosa (Plasmodiophoromycetes). Can. J. Bot. 63: 263-273.
- Neuhauser, S. & M. Kirchmair. 2009. Ligniera junci , a plasmodiophorid re-discovered in roots of Juncus in Austria. Österr. Z. Pilzk. 18: 151-157.