Species Of Ceratobasidium Research Articles

Ceratobasidium sp isolates from native orchid species of Western Ghats, India support enhanced growth of Phalaenopsis hybrid seedlings

Mycorrhiza-assisted cultivation of orchid seedlings has immense potential for enhanced growth and adaptability of orchids to facilitate conservation and cultivation with minimum application of nutrients and plant protection chemicals. Phalaenopsis hybrids are highly attractive and cultivated mostly as potted orchid plants and are prone to several fungal pathogens. The present study evaluates the effect of 4 orchid symbionts in combination with NPK fertilizer on the seedling growth of symbiotic seedlings of Phalaenopsis white and day-star hybrids under ex-vitro conditions. Four fungal isolates viz., Ceratobasidium_Wyd2 (MW595786; MTCC13384), Ceratobasidium_Idk (MW595787: MTCC13383), Ceratobasidium_Vs1 (OL374050; MTCC13377) and Ceratobasidium _Vs2 (OL374052: MTCC13378) grown on sterilized coir pith medium for 10 days and were transferred onto earthen pots for planting of seedlings. One-year-old seedlings used for the study possessed an average 2.70 g fresh weight. On conclusion of the experiment, after 6 months, the seedlings of day-star hybrid grown in the presence of both fungus and NPK fertilizer exhibited enhanced growth compared to either of them applied individually. The highest weight gain was supported by VS1 (12.4±1.8 g) followed by VS2 (10.7± 4.6 g) and Wyd2 (9.8±1.7 g). Those fungi also supported appreciable growth individually, giving 6.5±3.1, 6.9±2.2, and 6.5±0.8 g weight gain respectively. If the nutrient alone was applied, the weight gain was very low (2.8±0.9 g) nearly equal to control (1.8±1.8 g) without having fungi or nutrients. The mycorrhizae re-isolated from the roots of seedlings exhibiting enhanced growth were confirmed as Vs1 and Vs2 through sequencing of the ITS region. Formulation of a potting medium including Ceratobasidium species isolates VS1 and VS2 is thus possible to grow Phalaenopsis seedlings to get enhanced growth.

Diversity and specificity of orchid mycorrhizal fungi in a leafless epiphytic orchid, Dendrophylax lindenii and the potential role of fungi in shaping its fine-scale distribution

Orchids grow in diverse habitats worldwide with most (approximately 69%) growing on trees as epiphytes. Although orchid mycorrhizal fungi have been identified as potential drivers for terrestrial orchid distribution, the influence of these fungi on the fine-scale distribution of epiphytic orchids is poorly understood. In this study, we investigated the mycorrhizal fungal community and fine-scale distribution of Dendrophylax lindenii, a rare and endangered epiphytic orchid that is leafless when mature. We used amplicon sequencing to investigate the composition of orchid mycorrhizal fungi in the roots of 39 D. lindenii individuals in their natural habitat, the swamps of Florida. We compared the orchid mycorrhizal fungi of D. lindenii to those of co-occurring epiphytic orchids, as well as to the orchid mycorrhizal fungal communities of bark from potential host trees, with and without D. lindenii. Our results show that D. lindenii has a high specificity for a single Ceratobasidium species, which is widely distributed on phorophytes and detected in both wet and dry periods in the orchid’s habitat. This Ceratobasidium species was mostly absent or only recorded in low frequency in the roots of co-occurring epiphytic orchids. Phylogenetic analysis documented that this Ceratobasidium was conspecific with the strain that is used to germinate D. lindenii ex-situ. However, our findings suggest that laboratory germinated adult D. lindenii transplanted into the field had lower read abundances of this Ceratobasidium compared to naturally occurring plants. These findings suggest that this orchid mycorrhizal fungus may play a significant role in the fine-scale distribution of naturally occurring D. lindenii.

Initial Population Analysis and Mycorrhizal Fungi of the Leafless Epiphytic Orchid, Campylocentrum pachyrrhizum, in Florida

Campylocentrum pachyrrhizum Rchb.f. Rolfe, also known as the ribbon orchid, is native to southern Florida, the West Indies, and northern South America. In Florida, it is restricted to the Fakahatchee Strand and is currently state-listed as endangered, but virtually nothing is known about the orchid’s biology, ecology, and current status. The purpose of this study was to document ribbon orchid populations within the northern portion of the Fakahatchee Strand (Florida Panther NWR) and to identify some of the biotic and abiotic factors critical to its survival. During 2016–2022, a total of 118 ribbon orchids were recorded at five sites on 21 host trees comprising two species (Annona glabra, Fraxinus caroliniana). The majority (80%) were rooted on pop ash, and over half (54%) were rooted at the base of trees 100–150 cm above the high water mark. The number of orchids decreased from year to year, with the largest drop (2017–2018) coinciding with damage from Hurricane Irma. At the end of the 2022 survey, only 44 orchids remained. Mycorrhizal fungi isolated from two plants were identified as a Ceratobasidium species. We urge land managers to take immediate action to safeguard this species throughout southern Florida.

Small RNA Analyses of a Ceratobasidium Isolate Infected with Three Endornaviruses.

Isolates of three endornavirus species were identified co-infecting an unidentified species of Ceratobasidium, itself identified as a symbiont from within the roots of a wild plant of the terrestrial orchid Pterostylis vittata in Western Australia. Isogenic lines of the fungal isolate lacking all three mycoviruses were derived from the virus-infected isolate. To observe how presence of endornaviruses influenced gene expression in the fungal host, we sequenced fungus-derived small RNA species from the virus-infected and virus-free isogenic lines and compared them. The presence of mycoviruses influenced expression of small RNAs. Of the 3272 fungus-derived small RNA species identified, the expression of 9.1% (300 of 3272) of them were up-regulated, and 0.6% (18 of 3272) were down-regulated in the presence of the viruses. Fourteen novel micro-RNA-like RNAs (Cer-milRNAs) were predicted. Gene target prediction of the differentially expressed Cer-milRNAs was quite ambiguous; however, fungal genes involved in transcriptional regulation, catalysis, molecular binding, and metabolic activities such as gene expression, DNA metabolic processes and regulation activities were differentially expressed in the presence of the mycoviruses.

A new mycorrhizal species of Ceratobasidium (Ceratobasidiaceae) associated with roots of the epiphytic orchid Gomesa recurva from Brazilian Atlantic Forest

Species from Ceratobasidium are known as orchid mycorrhizal, plant pathogens or saprophytic. In mycorrhizal association with orchids, Ceratobasidium can establish a highly specific interaction. Gomesa recurva is an epiphytic orchid occurring in the Brazilian Atlantic Forest. In the present study mycorrhizal fungi were isolated from roots of G. recurva and its phylogenetic positions was investigated. A total of nine isolates were obtained directly from pelotons and submitted to phylogenetic analysis based on alignments of sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA. Phylogenetic analyzes, along with morphological data, revealed that isolates are distinct from all known Ceratobasidium species and a new species, namely Ceratobasidium gomesae sp. nov., is proposed. Given the dependence on mycorrhizae for germination and protocorm development, knowledge about orchid symbionts is an important factor in managing the conservation of these plants, and future studies may investigate the ability of C. gomesae to promote seed germination.

Isolation and identification of mycorrhizal fungus from an epiphytic orchid (Rhynchostylis retusa L. Bl.)

Isolation and identification of mycorrhizal fungi from the roots of Rhynchostylis retusa indicated that the cultural and microscopic features, namely colony appearance, colony colour, diameter of vegetative hyphae, presence of monilioid cells, right angle branching pattern of the fungal endophyte corroborated the identity of the fungus Rhizoctonia like anamorphs of Ceratobasidium species. Fungal identity was further confirmed through sequencing and analysis of internal transcribed spacer (ITS) sequences of the nuclear ribosomal DNA (nrDNA). ITS sequence of the isolate RhY10A6 (accession no. MN120903.1) showed > 99% similarity with several isolates of the teleomorphic fungus Ceratobasidium sp. in NCBI mega blast search. The phylogenetic analysis based on maximum parsimony method, this orchid mycorrhizal fungus clustered with several isolates of Ceratobasidium sp. or Rhizoctonia like fungi. It showed near distant relation with Ceratobasidium ramicola (GeneBank accession no. NR_138368.1) which is an orchid mycorrhizal fungus. Therefore, molecular characterization validated the morphological data. The techniques established in this orchid will facilitate to isolate and accurate identification of mycorrhizal fungus.

Two new Ceratobasidium species causing white thread blight on tropical plants in Brazil

White thread blight is one of the most common diseases affecting several tree species that grow in warm and humid regions. The typical symptoms of this disease include blighted leaves hanging by a white thread of fungal hyphae. Leaf samples exhibiting white thread blight symptoms were collected from neem (Azadirachta indica A. Juss) and Brazilian cherry pitanga (Eugenia uniflora L.) plants in Northeastern Brazil, and from Indian green-tea (Camellia sinensis (L.) O. Kuntze), coffee (Coffea arabica L.), and persimmon (Diospyros kaki L.) in agricultural areas neighboring the Atlantic forest in Southeastern Brazil. Fungal isolates were obtained indirectly from leaf fragments or directly by transferring mycelia and sclerotia to culture medium. Bright field and scanning electron microscopy images revealed the association of Rhizoctonia-like hyphae and basidiospores with the infected leaves. In pathogenicity tests, Rhizoctonia-like fungal isolates induced leaf necrosis on their hosts, and the pathogens were re-isolated from inoculated plants. Phylogenetic analyses based on sequences of the ITS rRNA region indicated the occurrence of Ceratobasidium lineages distinct from previously reported Ceratobasidium species. Our study leads to the description of two new species of Ceratobasidium: the fungal isolates from A. indica, C. sinensis, and E. uniflora were classified as Ceratobasidium niltonsouzanum sp. nov., and those obtained from C. arabica and D. kaki as Ceratobasidium chavesanum sp. nov.

Long-term cryopreservation of non-spore-forming fungi in Microbank™ beads for plant pathological investigations

Long-term preservation of experimental fungi without genetic, morphological, and pathogenic changes is of paramount importance in mycological and plant pathological investigations. Several cryogenic and non-cryogenic methods are available for the preservation of fungi, but the methods can be cumbersome, hazardous, expensive, and often not suitable for long-term storage of non-spore-forming (sterile) fungi. A method of preservation of spore-forming fungi in commercially available porous beads (Micrbank™) under cryogenic condition was successfully tested for three non-spore-forming basidiomycetes genera: Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) (n = 19), Ceratobasidium species (n = 1), and Waitea circinata (n = 3), and a non-spore forming ascomycetes, Sclerotinia sclerotiorum (n = 1). For comparison, spore-forming ascomycetous fungi, Alternaria alternata (n = 1), Bauveria basiana (n = 2), Botrytis cinerea (n = 1), Fusarium oxysporum f.sp. gladiolii (n = 1), Trichoderma spp. (n = 3), and Thielaviopsis basicola (n = 2) were also cryopreserved in Microbank beads. Viable fungal isolates of all test species were retrieved after five years of storage at −80 °C, which was longer than the viabilities of the corresponding isolates cryopreserved in agar plugs or colonized wheat seeds. Fungi revived from the Microbank beads maintained identical morphology and cultural characteristics of the parent isolates. Randomly selected Rhizoctonia isolates revived from the Microbank beads maintained respective pathological properties of the parent isolates; also, no mutation was detected in the internal transcribed spacer (ITS) ribosomal DNA when compared with respective cultures maintained at ambient temperature. This finding demonstrated the utility of cryopreservation in Microbank beads as a convenient alternative to conventional long-term preservation of a wide group of fungal cultures for plant pathological investigations and serves as the first report of using porous beads under cryogenic conditions for long-term storage of sterile fungi.

Mycorrhizal fungi isolated from native terrestrial orchids of pristine regions in Cordoba (Argentina).

Orchidaceae is a highly dependent group on the Rhizoctonia complex that includes Ceratorhiza, Moniliopsis, Epulorhiza and Rhizoctonia, for seed germination and the development of new orchid plants. Thus, the isolation and identification of orchid mycorrhizal fungi are important to understand the orchid-fungus relationship, which can lead to the development of efficient conservation strategies by in vivo germination of seeds from endangered orchid plants. The aim of our work was to isolate and characterize the different mycorrhizal fungi found in roots of terrestrial orchids from Cordoba (Argentina), and, to learn about the natural habit and fungal associations in the Chaco Serrano woodland pristine region. In this study, bloomed orchid root and rhizosphere soil samples were obtained in two times from Valle de Punilla during spring of 2007; samples were kept in plastic bags until processed within 48 hours, and mycorrhizal condition confirmed assessing peloton presence. A total of 23 isolates of the orchideous mycorrhizal Rhizoctonia complex were obtained. The isolates were studied based on morphological characters and ITS-rDNA sequences. Morphological characteristics as color of colonies, texture, growth rate, hyphal diameter and length and presence of sclerotia were observed on culture media. To define the number of nuclei per cell, the isolates were grown in Petri dishes containing water-agar (WA) for three days at 25 degrees C and stained with Safranine-O solution. The mycorrhizal fungi were grouped into binucleate (MSGib, 10 isolates) and multinucleate (MSGim, 13 isolates) based on morphological characteristics of the colonies. We obtained the ITS1-5.8s-ITS4 region that was amplified using primers ITSI and ITS4. Based on DNA sequencing, isolates Q23 and Q29 were found to be related to species of Ceratobasidium. Isolates Q24 and Q4 were related to the binucleated anastomosis group AG-C of Rhizoctonia sp. The rest of the isolates grouped in the Ceratobasidium clade without grouping. From our knowledge this is the first report of the asso- ciation of the AG-C testers with terrestrial orchids. A high specificity was observed in the symbiotic relationship. As the mycorrhizal fungal isolates were obtained from native orchids, they could be incorporated in conservation programes of endangered orchids in Argentina.

Taxonomic re-evaluation of the Ceratobasidium-Rhizoctonia complex and Rhizoctonia butinii, a new species attacking spruce

A taxonomic re-evaluation of the Ceratobasidium-Rhizoctonia group suggests that Ceratobasidium contains only the type species C. calosporum, which deviates in micromorphological and ultrastructural characters from all other species so far included in that genus. Rhizoctonia species are compared with the type species of Ceratobasidium, Cejpomyces, Oncobasidium, Tofispora, Waitea, and Ypsilonidium. The micromorphology, ultrastructure, cellular interaction with the host, and molecular phylogeny of a Rhizoctonia species parasitic on needles and young shoots of Picea abies have been studied. The parasite has been known for a long time, but misinterpreted, and not named so far. Rhizoctonia butinii is described and compared with related species of the genus.

Ceratobasidium Root Rot: A New Disease of Watermelon in Arizona

To our knowledge, Ceratobasidium species have never been previously reported as a pathogen of watermelon anywhere in the United States. Because of the recent reports in Italy and confirmed incidences in major watermelon production areas in Arizona, this disease should be recognized as a potential problem in watermelon. Accepted for publication 13 November 2013. Published 25 November 2013.

Evidence that the Ceratobasidium-like white-thread blight and black rot fungal pathogens from persimmon and tea crops in the Brazilian Atlantic Forest agroecosystem are two distinct phylospecies.

The white-thread blight and black rot (WTBR) caused by basidiomycetous fungi of the genus Ceratobasidium is emerging as an important plant disease in Brazil, particularly for crop species in the Ericales such as persimmon (Diospyros kaki) and tea (Camellia sinensis). However, the species identity of the fungal pathogen associated with either of these hosts is still unclear. In this work, we used sequence variation in the internal transcribed spacer regions, including the 5.8S coding region of rDNA (ITS-5.8S rDNA), to determine the phylogenetic placement of the local white-thread-blight-associated populations of Ceratobasidium sp. from persimmon and tea, in relation to Ceratobasidium species already described world-wide. The two sister populations of Ceratobasidium sp. from persimmon and tea in the Brazilian Atlantic Forest agroecosystem most likely represent distinct species within Ceratobasidium and are also distinct from C. noxium, the etiological agent of the first description of white-thread blight disease that was reported on coffee in India. The intraspecific variation for the two Ceratobasidium sp. populations was also analyzed using three mitochondrial genes (ATP6, nad1 and nad2). As reported for other fungi, variation in nuclear and mitochondrial DNA was incongruent. Despite distinct variability in the ITS-rDNA region these two populations shared similar mitochondrial DNA haplotypes.

Vascular Streak Dieback of cacao in Southeast Asia and Melanesia: in planta detection of the pathogen and a new taxonomy

Vascular Streak Dieback (VSD) disease of cacao (Theobroma cacao) in Southeast Asia and Melanesia is caused by a basidiomycete (Ceratobasidiales) fungus Oncobasidium theobromae (syn. =Thanatephorus theobromae). The most characteristic symptoms of the disease are green-spotted leaf chlorosis or, commonly since about 2004, necrotic blotches, followed by senescence of leaves beginning on the second or third flush behind the shoot apex, and blackening of infected xylem in the vascular traces at the leaf scars resulting from the abscission of infected leaves. Eventually the shoot apex is killed and infected branches die. In susceptible cacao the fungus may grow through the xylem down into the main stem and kill a mature cacao tree. Infections in the stem of young plants prior to the formation of the first 3–4 lateral branches usually kill the plant. Basidiospores released from corticioid basidiomata developed on leaf scars or along cracks in the main vein of infected leaves infect young leaves. The pathogen commonly infects cacao but there are rare reports from avocado. As both crops are introduced to the region, the pathogen is suspected to occur asymptomatically in native vegetation. The pathogen is readily isolated but cultures cannot be maintained. In this study, DNA was extracted from pure cultures of O. theobromae obtained from infected cacao plants sampled from Indonesia. The internal transcribed spacer region (ITS), consisting of ITS1, 5.8S ribosomal RNA and ITS2, and a portion of nuclear large subunit (LSU) were sequenced. Phylogenetic analysis of ITS sequences placed O. theobromae sister to Ceratobasidium anastomosis groups AG-A, AG-Bo, and AG-K with high posterior probability. Therefore the new combination Ceratobasidium theobromae is proposed. A PCR-based protocol was developed to detect and identify C. theobromae in plant tissue of cacao enabling early detection of the pathogen in plants. A second species of Ceratobasidium, Ceratobasidium ramicola, identified through ITS sequence analysis, was isolated from VSD-affected cacao plants in Java, and is widespread in diseased cacao collected from Indonesia.

The rare Australian epiphytic orchid Sarcochilus weinthalii associates with a single species of Ceratobasidium

Sarcochilus weinthalii is a rare, epiphytic orchid largely restricted to the dry rainforests of eastern Australia. Part of the conservation procedures for the orchid includes isolation and identification of the associated mycorrhizal fungus. In this study the mycorrhizal fungal partner of the species was determined through extraction and sequencing of DNA from both colonised orchid roots and pure fungal cultures grown out from orchid roots. A single species of Ceratobasidium predominated in the orchid suggesting that the orchid displays narrow fungal specificity. This mycorrhizal fungus can now be used in conservation procedures involving ex situ growth and the reintroduction of plants to the natural state.

Codiversification of orchids (Pterostylidinae) and their associated mycorrhizal fungi

Fungal symbionts involved in mycorrhizal associations are known to vary considerably in both specificity and the level of benefits conferred on their plant hosts. For orchids, association with a suitable mycorrhizal fungus is vital for successful germination, growth and establishment. Using an evolutionarily distinct group of Australasian terrestrial orchids, the Pterostylidinae (Cranichiadeae: Orchidaceae), we assessed potential codiversification and the level of response between this diverse host group (~250 species) and their associated fungal symbionts. All fungal isolates recovered (~200 from 41 host species covering all major orchid clades) were identified as species of Ceratobasidium, which clustered into strongly supported groups using nuclear (ITS) and mitochondrial (ML 4–5) gene sequences. Three clades within the Pterostylidinae phylogeny showed associations with specific fungal clades. The results suggest the occurrence of local adaptation by the fungal symbionts to the orchid host, particularly in diverse and widespread host taxa. Results of cross-inoculation in vitro germination experiments revealed correlations between certain mycorrhizal fungal clades and particular orchid taxa, with germination generally being most effective when seeds were inoculated with fungal strains from the same clade as found naturally associated with the orchid species. We found only general congruence between the orchid and fungal phylogenies, suggesting that strict codivergerence between these orchids and their mycorrhizal associates has not occurred at the broad level of resolution studied.

Phylogenetic placement of plant pathogenic Sclerotium species among teleomorph genera

Phylogenetic analyses and morphological characteristics were used to assess the taxonomic placement of eight plant-pathogenic Sclerotium species. Members of this genus produce only sclerotia and no fruiting bodies or spores, so Sclerotium species have been difficult to place taxonomically. Sequences of rDNA large subunit (LSU) and internal transcribed spacer (ITS) regions were determined for isolates of Sclerotium cepivorum, S. coffeicola, S. denigrans, S. hydrophilum, Ceratorhiza oryzae-sativae, S. perniciosum, S. rhizodes, S. rolfsii and S. rolfsii var. delphinii. Parsimony analysis grouped two species previously thought to be in the Basidiomycota, S. denigrans and S. perniciosum, within the Ascomycota; these species were found to have affinities with the teleomorph genera Sclerotinia and Stromatinia and the asexual Sclerotium cepivorum, which was known earlier to be related to Sclerotinia species. The other Sclerotium species were placed in one of two basidiomycetous groups, genera Athelia or Ceratobasidium. Based on rDNA analysis and morphology the basidiomycetous Sclerotium hydrophilum and S. rhizodes were transferred to genus Ceratorhiza, the anamorph of Ceratobasidium species. Sclerotium coffeicola was found to be close to S. rolfsii var. delphinii and S. rolfsii var. rolfsii, which was shown earlier to have an Athelia teleomorph.

Ceratobasidium Oryzae-Sativae Sp. Nov., The Teleomorph ofRhizoctonia Oryzae-SativaeandCeratobasidium Setariae Comb. Nov., The Probable Teleomorph ofRhizoctonia Fumigata Comb. Nov.

The teleomorph of Rhizoctonia oryzae-sativae is described as Ceratobasidium oryzae-sativae sp. nov. It differs from other known Ceratobasidium species because it has two sterigmata per basidium in conjunction with typically subglobose basidiospores. Ceratobasidium setariae comb. nov. (=Hypochnus setariae) is morphologically similar to C. oryzae-sativae. The description of the sclerotial state of C. setariae conforms to Sclerotium fumigatum and C. setariae is postulated to be the teleomorph of S. fumigatum. Sclerotium fumigatum is binucleate and is placed in the genus Rhizoctonia.

ENDOPHYTES OF WILD ORCHIDS NATIVE TO ITALY: THEIR MORPHOLOGY, CARYOLOGY, ULTRASTRUCTURE AND CYTOCHEMICAL CHARACTERIZATION

SummaryIsolates of Rhizoctonia sp. obtained from the terrestrial orchids Dactylorhiza sambucina (L.) Soó, D. maculata (L.) Soó and Platanthera bifolia (L.) L. C. M. Richard, collected in Piedmont (Italy) were studied in the following characters: macroscopic and microscopic morphology, growth rate, ultrastructure of the septal pore apparatus, number of nuclei per cell and cytochemistry of the hyphal and monilioid cells. On the basis of cultural and morphometric characters, the isolates were divided into three groups, which are described in detail. No perfect stage was produced in culture. Although the identification of species of Rhizoctonia‐like fungi without perfect stages is extremely difficult, a comparison of our data with that in the literature leads to the probable identification of group I isolates as a species of Ceratobasidium, group II isolates as a species of Thanatephorus and those of group III as a species of Tulasnella or Sebacina.

THE MYCORRHIZAL RELATIONSHIPS OF AUSTRALIAN ORCHIDS

SUMMARYThe symbiotic associations of Australian orchids have been examined by isolating Rhizoctonia endophytes from orchids growing in the field and by symbiotic germination of orchid seed. Many Rhizoctonia isolates fruited and were identified to their perfect states.The isolation studies showed considerable specificity in association between many orchids and their endophytes. In particular Sebacina vermifera was generally associated with Caladenia and several related genera. Tulasnella calospora was closely associated with Diuris and Orthoceras and it and other species of Tulasnella with Thelymitra and Dendrobium. Ceratobasidium cornigerum was associated with Prasophyllum and Pterostylis and, with other species of Ceratobasidium, with orchids of the subtribe Sarcanthinae. Specificity, however, was not absolute for different Rhizoctonias may occur in an orchid either alone or with the more usual endophyte. A few orchids had a wide range of endophytes commonly present.Symbiotic germination studies generally substantiated the field isolations but showed further levels of specificity in that isolates of a fungus often differed markedly in their ability to germinate seed of a host or of different hosts under the conditions used.With orchids specificity seemed to occur at different levels, from species to at least subtribe, though the data are imprecise. If there is specificity to subtribe then there are some anomalies in classification. For instance all Caladeniinae sampled were associated with Sebacina vermifera except Lyperanthus which was associated with a wide range of other fungi. Microtis and Prasophyllum, though not considered closely associated, are placed together in the Prasophyllinae; their endophytes are quite different.

Morphology, development, and cytochemistry of the hyphae and sclerotia of species in the Rhizoctonia complex

A detailed comparison of the gross morphology of hyphae, monilioid cells, and sclerotial formation and structure of 17 isolates of species in seven genera of the Rhizoctonia complex were studied. Cytochemistry of both hyphal and sclerotial cells was also studied. Gross morphology of hyphae was similar in many of the isolates and was considered of limited taxonomic value. Sclerotial formation in species of Thanatephorus, Waitea, Aquathanatephorus, and possibly Ceratobasidium was of the monilioid cell type. That of Athelia was of the hyphal strand type. Although initially similar, mature sclerotia in each of the genera showed great diversity. Most sclerotia of Thanatephorus were constructed of loosely arranged monilioid cells. Those in Ceratobasidium developed a marginal rind; Aquathanatephorus, a pitted surface and hyphal mat; Waitea, a bilaminate condition with elongate marginal and globose medullary cells; and Athelia, a complex tetralaminate structure. Distribution and concentration of carbohydrates, proteins, and lipids differed in the various genera. The strong dextrinoid reaction of the cytoplasm of Thanatephorus and Aquathanatephorus, accompanied by higher total lipids in cell walls and septa, was of significance. Stronger reactions for cellulose were found in species of Ceratobasidium, while cellulose appeared more concentrated in sclerotial cells than in hyphal cells of Thanatephorus. Lipids were deposited more abundantly in sclerotial cells than in hyphal cells.