A Morphological and Physiological Study of Gilbertella in India

Abstract

The genus Gilbertella has recently been described by Hesseltine (1960) after a careful study of Eddy's species, Choanephora persicaria, a synonym of Gilbertella persicaria (Eddy) Hesseltine. This peculiar species resembles members of the Choanephoraceae in one essential character, the presence of the sporangiospores with several hyaline appendages at either end of each. Also, it shows striking similarity with members of the Mucoraceae in forming the Mucor-type and not the Choanephora-type of zygospores. If we accept the precedent existing in the Mucorales for placing greater emphasis on asexual than sexual structure for delimitation of the families, we have to retain this species in the Choanephoraceae. But if we consider the view of attaching more importance to the sexual stage of fungi in determining natural relationship, we have to include this species in the Mucoraceae, after suitably modifying the concept of the family to include forms with appendaged sporangiospores as well. This genus has never been reported from India but in our isolations of Mucorales from varied substrates we have found it to be quite common on the decomposing flowers of Thevetia neriifolia Juss. (yellow oleander) and also in humus soil in Allahabad. We have collected 10 isolates from different places; the colony of all the isolates had a brownish tint. These isolates resemble the type culture of Gilbertella persicaria except for the slow growth on SMA 1 medium and the much branched sporangiophores in addition to simple ones. The latter characteristic has not been described by either Eddy (1925) or Hesseltine (1960) and was absent in the two isolates of Gilbertella persicaria kindly sent by Dr. C. W. Hesseltine. Mating reaction between several isolates of this species showed no positive results. Dr. Hesseltine, who had kindly examined our culture M-59 and mated it with NRRL 2357, a plus strain of Gilbertella persicaria, commented that though no perfect line of zygospores was seen because of the different