The host-range of Paraphysoderma sedebokerensis, a chytrid that infects Haematococcus pluvialis

Figures & data

Figs 1–6. Infected Haematococcus pluvialis culture stained with Nile red. Images are either in phase contrast (1, 3 and 5), or under fluorescent light (2, 4 and 6). Figs 1, 2: Nile-red staining enables very young sporangium to be detected. Figs 3, 4: lipid globules inside the chytrid's sporangium. Figs 5, 6: Staining of infected culture allows for the algal cells carrying fungal sporangia to be counted. Arrows indicate the location of a chytrid sporangium, which is undetectable under phase contrast in dense culture.

Fig. 7. Development of ‘epidemics’ in different algal species at their logarithmic stage, during the period of 7 days. Each point on the graph represents the percentage of algal cells observed carrying Paraphysoderma sedebokerensis (nom. prov.) sporangium. Haematococcus pluvialis Flotow 1844em.Wille SCCAP K-0084 (•), Chlorella zofigiensis Donz CCAP 211/14 (▪), Scenedesmus vacuolatus SAG 211-8b(○), Muriella zofigiensis SAG 4.80 (▴), Scotiellopsis oocystiformis SAG 277-1(♦).

Table 1. A survey of the susceptibility of algal species to infection by P. sedebokerensis in vegetative and nitrogen-starved stages.

	Development of epidemic
Algal strain	Vegetative stage	N-starved
Haematococcus pluvialis Flotow 1844em.Wille SCCAP K-0084	100	100
Chlorella zofigiensis Donz CCAP 211/14	100	0
Chlorella emersonii CCAP 211/11N	1	0
Chlorella vulgaris SAG 211-8L	0.4	0
Scenedesmus vacuolatus SAG 211-8b	17	0
Scenedesmus vacuolatus SAG 211-15	0.4	0
Scenedesmus obliquus SAG 276-3a	0.4	0
Muriella zofigiensis SAG 4.80	8	0
Chlorococcum sp. UTEX 819	0.8	0
Chlamydomonas nivalis UTEX 2824	0.1	0
Chlorogonium elongatum SAG 12-2b	0	0
Monoraphidium braunii SAG 202-7b	0	0
Scotiellopsis oocystiformis SAG 277-1	3	0
Extent of fungal abundance in the culture was measured daily up to 7 days. The occurrence of adhesion and the estimated extent of the epidemic–prevalence of infection, Pr–after 7 days are represented.