Cyllamyces icaris sp. nov., a new anaerobic gut fungus with nodular sporangiophores isolated from Indian water buffalo (Bubalus bubalis).

Abstract

A new species of anaerobic rumen fungus (Neocallimastigales) Cyllamyces icaris was isolated from the dung sample of Indian water buffalo ( Bubalus bubalis). This fungus belongs to the genus Cyllamyce and can be easily distinguished from the genus Caecomyces by the presence of rhizoids as well as multiple intermittent bulbous rhizoids. C.icaris resembles the type species Cyllamyces aberensis in multiple oval sporangia, nodular branched short sporangiophores and uniflagellate zoospores but differs from it in a polycentric development, the presence of distinct rhizoids, multiple bulbous holdfast and fastidious growth pattern (complete life cycle within 14-16 hrs). The sporangium though fewer in number (1-3 on each sporangiophore) had a diameter of 19.33 ±6.78µm , much larger compared to that of C. aberensis (14.7 µm). Zoospores were observed to have a diameter range of 7.7 - 14.13 m (11.13 ± 1.39 µm; n= 480) while the average length of the flagella was 59.50 ± 10.33 µm (n= 410). From an initial diameter of 14 m (14.63 ± 0.26 m [Mean ± SD]; n=100), the bulbous holdfast grew up to 86 m (56.64 ± 13.42; n= 150) after 24 h. The Internal transcribed spacer 1 sequence analysis revealed the unique motif sequence in Variable region I and thus a ninth motif sequence in Variable region I for Cyllamyces icaris is included. The motif sequences for variable regions II, III and IV were obtained at 10, 13 and 8, respectively and were similar to those described earlier for Cyllamyces aberensis. As per morphology, Cyllamyces icaris could be considered as the interconnecting link between the rhizoidal and the non-rhizoidal fungus. The rhizoid penetrates while the intermittent bulbous rhizoid helps in the rupturing of fibrous feed particles. This fungus holds special significance in the degradation of poor quality feed in ruminants.