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Spore development in Periconia species III. Remispora cucullata
Notes and brief articles SPORE DEVELOPMENT IN PERIGONIA SPECIES
III.REMISPORA GUGULLATA BY S. E. BUNNING AND D. A . GRIFFITHS
Botany Department, University of Hong Kong , Hong Kong Development of the conidia of Remispora cucullata is described from observations using light and electron microscopy and compared with development of the conidia of Periconia prolifica . In 1969, Kohlmeyer identified Remispora cucullata as the teleomorph of Periconia prolifica, by means of single ascospore isolations. This paper reports ultrastructural features of conidial production in R. cucullata and these are compared with similar observations on a local isolate of P . prolifica (Bunning & Griffiths, 1982). Remispora cucullata (ATCC 18576) was cultured on glucose/yeast/artificial sea water agar and malt extract/artificial sea water agar at 25-30 °C, and examined by light, transmission and scanningelectron microscopy, using the methods of Bunning & Griffiths (1982). Growth of R. cucullata was much slower than that of P. prolifica; a dark brown fluffy mycelium was produced. However, conidiation in R . cucullata was much denser. The conidia of R. cucullata were produced in chains, frequently branched, producing clusters (Fig. 1), whereas the local isolate of P . prolifica produced conidia in unbranched chains. The conidia of R. cucullata, like those of P . prolifica, were smooth-walled, but in R. cucullata they were both smaller (7-8 pm compared with 12 pm for P. prolifica), and much more regularly spherical in shape (Fig. 2 ). SEM pictures clearly illustrated the branched form of the chains which, like P . prolifica, are terminated at the apex by a mature conidium (F ig . 3). However, unlike in P. prolifica, there appeared to be a break in the outer wall of the conidium, at its junction with the next spore in the chain (Fig. 4) . TEM observations on the method ofdevelopment of the chains in R. cucullata show that in some cases a similar method to that observed in P . prolifica occurs, i.e. the blowing out of the conidiophore apex, followed by elongation and delimitation of conidia by septum production (Figs 5, 6). However, it was also frequently observed that elongation of a chain was brought about by an enteroblastic 'blowing out' process, the conidiogenous cell
acting as a phialide-like structure (F ig. 7). It is suggested from Fig. 7 that the lower conidium gave rise to the upper conidium by a blowing out of the apex. The younger conidium has then proceeded to mature (n ote thicker wall) before that which produced it , i.e. acropetal production followed by basipetal maturation. This process causes the rupture and separation of wall layers of the previously formed conidium or conidiogenous cell, giving the characteristic effect observed in Fig. 7. This separation of wall layers makes it difficult to say whether the conidial initial is clothed in an extension of the inner, or by a newly formed wall. In conclusion, the conidia of P. prolifica and R. cucullata show a number of similarities, though the local isolate of P . prolifica has larger conidia with slightly thinner walls, which are produced exclusively in unbranched chains. However, there are differences in the methods of conidiogenesis in these two fungi : P . prolifica produces conidia exclusively by thallic septation whilst R. cucullata produces conidia not only by this method by also by a phialidic-like mode of conidiogenesis. Such differences raise questions as to the identification of Remispora cucullata as the teleomorph of Periconia prolifica. Alternatively, if a definite relationship between R. cucullata and its anamorph can be established unequivocally then the doubt would lie in whether or not our isolate of P. prolifica has been correctly identified. However, the isolate has been identified as P . prolifica by two authorities (E. B . Gareth j ones; Portsmouth Polytechnic; J. Kohlmeyer, Institute of Marine Sciences, University of North Carolina), and accepted by ATCC as an isolate of P. prolifica (ATCC 48623) . If both acceptance of the identification of the isolate, and the relationship between P. prolifica and R. cucullata are correct, then the results presented here would have to acknowledge the greater variability possible in conidial production within a
Figs. 1-4. Remispora cucullata , Fig. 1. L.M. Cluster of conidia showing branched chains. Fig. z. L.M. Smooth-walled spherical conidia Fig. 3. SEM. Branched chains of conidia, with maturing conidia at apices. Fig. 4. SEM. Chain of conidia showing' frill' (arrow) where outer wall has broken during spore ontogeny.
Trans . Br, mycol. Soc . 83 (1), (19 84)
Pr inted in Great Britain
Notes and brief articles
Trans. Br, mycol. Soc. 83 (1), (1984)
Printed in Great Britain
186
Trans. Br. mycol. Soc. 83 (1), (1984)
Notes and brief articles
Printed in Great Britain
Notes and brief articles species than has perhaps been previously recognized. If this is the case, then great care will be required in utilizing conidiogenesis as a taxonomic criterion in establishing species. This work was undertaken as part of an M.Phil. Project at the University of Hong Kong by one of us (S.E.B.).
REFERENCES
S. E. & GRIFFITHS, D. A. (1982). Spore development in Periconia species. 1. P. prolifica and P. macrospinosa. Transactions of the British Mycological Society 78, 147-159. KOHLMEYER, J. (1969). Marine fungi of Hawaii including the new genus Heliascus. Canadian Journal of Botany 47,146 9- 1 4 87 .
BUNNING,
Figs 5-6. Remispora cucullata Fig. 5. TEM. Production of conidia by septation of the conidiogenous cell. Note the mature thick-walled conidium below. Fig. 6. TEM. Chain of conidia formed by septation of the conidiogenous cell. Fig. 7. TEM. Rupture of wall producing' frill' during production of upper conidium.
Trans. Br . mycol, Soc. 83 (1), (1984)
Printed in Great Britain
III.REMISPORA GUGULLATA BY S. E. BUNNING AND D. A . GRIFFITHS
Botany Department, University of Hong Kong , Hong Kong Development of the conidia of Remispora cucullata is described from observations using light and electron microscopy and compared with development of the conidia of Periconia prolifica . In 1969, Kohlmeyer identified Remispora cucullata as the teleomorph of Periconia prolifica, by means of single ascospore isolations. This paper reports ultrastructural features of conidial production in R. cucullata and these are compared with similar observations on a local isolate of P . prolifica (Bunning & Griffiths, 1982). Remispora cucullata (ATCC 18576) was cultured on glucose/yeast/artificial sea water agar and malt extract/artificial sea water agar at 25-30 °C, and examined by light, transmission and scanningelectron microscopy, using the methods of Bunning & Griffiths (1982). Growth of R. cucullata was much slower than that of P. prolifica; a dark brown fluffy mycelium was produced. However, conidiation in R . cucullata was much denser. The conidia of R. cucullata were produced in chains, frequently branched, producing clusters (Fig. 1), whereas the local isolate of P . prolifica produced conidia in unbranched chains. The conidia of R. cucullata, like those of P . prolifica, were smooth-walled, but in R. cucullata they were both smaller (7-8 pm compared with 12 pm for P. prolifica), and much more regularly spherical in shape (Fig. 2 ). SEM pictures clearly illustrated the branched form of the chains which, like P . prolifica, are terminated at the apex by a mature conidium (F ig . 3). However, unlike in P. prolifica, there appeared to be a break in the outer wall of the conidium, at its junction with the next spore in the chain (Fig. 4) . TEM observations on the method ofdevelopment of the chains in R. cucullata show that in some cases a similar method to that observed in P . prolifica occurs, i.e. the blowing out of the conidiophore apex, followed by elongation and delimitation of conidia by septum production (Figs 5, 6). However, it was also frequently observed that elongation of a chain was brought about by an enteroblastic 'blowing out' process, the conidiogenous cell
acting as a phialide-like structure (F ig. 7). It is suggested from Fig. 7 that the lower conidium gave rise to the upper conidium by a blowing out of the apex. The younger conidium has then proceeded to mature (n ote thicker wall) before that which produced it , i.e. acropetal production followed by basipetal maturation. This process causes the rupture and separation of wall layers of the previously formed conidium or conidiogenous cell, giving the characteristic effect observed in Fig. 7. This separation of wall layers makes it difficult to say whether the conidial initial is clothed in an extension of the inner, or by a newly formed wall. In conclusion, the conidia of P. prolifica and R. cucullata show a number of similarities, though the local isolate of P . prolifica has larger conidia with slightly thinner walls, which are produced exclusively in unbranched chains. However, there are differences in the methods of conidiogenesis in these two fungi : P . prolifica produces conidia exclusively by thallic septation whilst R. cucullata produces conidia not only by this method by also by a phialidic-like mode of conidiogenesis. Such differences raise questions as to the identification of Remispora cucullata as the teleomorph of Periconia prolifica. Alternatively, if a definite relationship between R. cucullata and its anamorph can be established unequivocally then the doubt would lie in whether or not our isolate of P. prolifica has been correctly identified. However, the isolate has been identified as P . prolifica by two authorities (E. B . Gareth j ones; Portsmouth Polytechnic; J. Kohlmeyer, Institute of Marine Sciences, University of North Carolina), and accepted by ATCC as an isolate of P. prolifica (ATCC 48623) . If both acceptance of the identification of the isolate, and the relationship between P. prolifica and R. cucullata are correct, then the results presented here would have to acknowledge the greater variability possible in conidial production within a
Figs. 1-4. Remispora cucullata , Fig. 1. L.M. Cluster of conidia showing branched chains. Fig. z. L.M. Smooth-walled spherical conidia Fig. 3. SEM. Branched chains of conidia, with maturing conidia at apices. Fig. 4. SEM. Chain of conidia showing' frill' (arrow) where outer wall has broken during spore ontogeny.
Trans . Br, mycol. Soc . 83 (1), (19 84)
Pr inted in Great Britain
Notes and brief articles
Trans. Br, mycol. Soc. 83 (1), (1984)
Printed in Great Britain
186
Trans. Br. mycol. Soc. 83 (1), (1984)
Notes and brief articles
Printed in Great Britain
Notes and brief articles species than has perhaps been previously recognized. If this is the case, then great care will be required in utilizing conidiogenesis as a taxonomic criterion in establishing species. This work was undertaken as part of an M.Phil. Project at the University of Hong Kong by one of us (S.E.B.).
REFERENCES
S. E. & GRIFFITHS, D. A. (1982). Spore development in Periconia species. 1. P. prolifica and P. macrospinosa. Transactions of the British Mycological Society 78, 147-159. KOHLMEYER, J. (1969). Marine fungi of Hawaii including the new genus Heliascus. Canadian Journal of Botany 47,146 9- 1 4 87 .
BUNNING,
Figs 5-6. Remispora cucullata Fig. 5. TEM. Production of conidia by septation of the conidiogenous cell. Note the mature thick-walled conidium below. Fig. 6. TEM. Chain of conidia formed by septation of the conidiogenous cell. Fig. 7. TEM. Rupture of wall producing' frill' during production of upper conidium.
Trans. Br . mycol, Soc. 83 (1), (1984)
Printed in Great Britain