Three orchid genera, Paphiopedilum, Cymbidium, and Dendrobium, are among the most heavily traded ornamental plants in Thailand. In this study, 27 isolates of Rhizoctonia-like fungi were isolated from ...root sections of mature orchids in the three orchid genera, collected from diverse horticultural settings in Chiang Mai and Chiang Rai provinces of Thailand. Fungal identification was done by the morphological characterization, the comparison of the internal transcribed spacer and 5.8S ribosomal DNA sequences, and the phylogenetic analysis. Epulorhiza repens was found to be the most common species found in the roots of various species of all three orchid genera, whereas Epulorhiza calendulina-like isolates were strictly found in the roots of Paphiopedilum species. We have also isolated and described an anamorph of Tulasnella irregularis, four new anamorphic species in the genus Tulasnella, and a new anamorphic species in the family Tulasnellaceae. Our study provides information on diversity of root-associated fungi of the orchid genera and at the sampling sites that were rarely addressed in the previous studies.
Species of
are commonly found in many plant hosts as pathogens, endophytes and occasionally saprobes. Twenty-two
strains were isolated from three
species -
,
and
, as well as three unidentified ...species. The taxa were identified using morphological characterisation and phylogenetic analyses of ITS, GAPDH, ACT and ß-tubulin sequence data. This is the first time to identify endophytic fungi from
orchids using the above method. The known species,
,
,
and
were identified as fungal endophytes of
spp., along with the new species,
,
,
,
and
, which are introduced in this paper. One strain is recorded as an unidentified species. Corn meal agar is recommended as a good sporulation medium for
species. This is the first report of fungal endophytes associated with
and
.
,
, and
are new host records for Thailand.
The nodule autoregulation receptor kinase (GmNARK) of soybean (Glycine max) is essential for the systemic auto-regulation of nodulation. Based on quantitative reverse-transcriptase polymerase chain ...reaction, GmNARK is expressed to varying levels throughout the plant; the transcript was detected at high levels in mature leaves and roots but to a lesser extent in young leaves, shoot tips, and nodules. The transcript level was not significantly affected by Bradyrhizobium japonicum during the first week following inoculation. In addition, the activities of the promoters of GmNARK and Lotus japonicus HAR1, driving a β-glucuronidase (GUSPlus) reporter gene, were examined in stably transformed L. japonicus and transgenic hairy roots of soybean. Histochemical GUS activity in L. japonicus plants carrying either a 1.7-kb GmNARKprGUS or 2.0-kb LjHAR1prGUS construct was clearly localized to living cells within vascular bundles, especially phloem cells in leaves, stems, roots, and nodules. Phloem-specific expression also was detected in soybean hairy roots carrying these constructs. Our study suggests that regulatory elements required for the transcription of these orthologous genes are conserved. Moreover, rapid amplification of 5' cDNA ends (5' rapid amplification of cDNA ends) revealed two major transcripts of GmNARK potentially originating from two TATA boxes. Further analysis of the GmNARK promoter has confirmed that these two TATA boxes are functional. Deletion analysis also located a region controlling phloem-specific expression to a DNA sequence between 908 bp and 1.7 kb upstream of the translation start site of GmNARK.
Fungi are an understudied, biotechnologically valuable group of organisms. Due to the immense range of habitats that fungi inhabit, and the consequent need to compete against a diverse array of other ...fungi, bacteria, and animals, fungi have developed numerous survival mechanisms. The unique attributes of fungi thus herald great promise for their application in biotechnology and industry. Moreover, fungi can be grown with relative ease, making production at scale viable. The search for fungal biodiversity, and the construction of a living fungi collection, both have incredible economic potential in locating organisms with novel industrial uses that will lead to novel products. This manuscript reviews fifty ways in which fungi can potentially be utilized as biotechnology. We provide notes and examples for each potential exploitation and give examples from our own work and the work of other notable researchers. We also provide a flow chart that can be used to convince funding bodies of the importance of fungi for biotechnological research and as potential products. Fungi have provided the world with penicillin, lovastatin, and other globally significant medicines, and they remain an untapped resource with enormous industrial potential.
Orchidaceae is one of the largest flowering plant families of the plant kingdom. The habitats of orchids are highly diverse, ranging from tree bark and damp forest floors to rock crevices, sandy ...dunes and semi-arid deserts. The diversity of endophytes (internal symbiotic fungi) associated with orchids is enormous. Most studies of endophytic fungi from orchids in the past have focused on mycorrhizal endophytes (internal symbiotic fungi associated with plant roots). There has, however, been an increasing trend to study non-mycorrhizal endophytes from orchids because of their physiological roles and their potential as sources of novel bioactive compounds. This review discusses the methods used in the isolation and identification of endophytic fungi from orchids, their diversity and host-specificity, their significance in orchid conservation and cultivation, and their potential application in the discovery of bioactive compounds.
This protocol is used to induce transgenic roots on soybean to study the function of genes required in biological processes of the root. Young seedlings with unfolded cotyledons are infected at the ...cotyledonary node and/or hypocotyl with Agrobacterium rhizogenes carrying the gene construct to be tested and the infection sites are kept in an environment of high humidity. When the emerged hairy roots can support the plants, the main roots are removed and the transgenic roots can be tested. Using this method, almost 100% of the infected plants form hairy roots within 1 month from the start of the experiments.
• This study dedicated to symbiotic seed germination of epiphytic orchids. • Asymbiotic and symbiotic seed germination were compared. • Effectiveness of eight putative mycorrhizal fungi in promoting
...in vitro orchid seed germination was compared. • Seven fungal isolates were confirmed as orchid mycobionts and one fungal isolate was confirmed as saprotrophic. • Compatible fungi could perform better or equal to Murashige and Skoog but not all orchid mycobionts enhanced the protocorm development.
In vitro symbiotic seed germination is an important tool not only for the study of orchid-fungus specificity but also for the production of mycobiont-infected healthy seedlings that could be valuable for both horticultural and conservation purposes. The current study compared effectiveness of eight putative orchid mycorrhizal fungi obtained from mature orchids in the genera
Paphiopedilum,
Cymbidium and
Dendrobium, in promoting
in vitro seed germination and protocorm development of
Grammatophyllum speciosum Blume and
Dendrobium draconis Rchb. f., native Thai orchids. The developmental stages of seeds and protocorms cultured on Murashige and Skoog (MS) medium, oat meal agar (OMA), or OMA inoculated with one of the eight fungal isolates were evaluated weekly. Two isolates of
Epulorhiza repens (Bernard) Moore (=anamorphic species of
Tulasnella calospora (Boud.) Juel), Da-KP-0-1 and Pv-PC-1-1, were found to be the most effective fungi in promoting protocorm development of
G. speciosum. At week 13, protocorms co-cultured with either one of these two fungal isolates, on the average, were significantly more advanced than those sown on OMA. Protocorms co-cultured with isolate Pv-PC-1-1 were also significantly more advanced than those cultured on MS medium. For
D. draconis seed germination, three fungal isolates of different anamorphic species of
Tulasnella, C1-DT-TC-1, Pv-PC-1-1, and C3-DT-TC-2, were found to be the most effective fungi in promoting protocorm development. However, none of these fungal isolates outperformed MS medium. Additionally, the compatibility between the fungal isolates tested and the two orchid species was discussed.
► Asymbiotic and symbiotic seed germination of four Dendrobium species were compared. ► Effectiveness of five Epulorhiza isolates in promoting germination was evaluated. ► Compatible fungi performed ...as good as Murashige and Skoog medium. ► Epulorhiza isolates are potential germination promoting mycobionts of many orchids.
In order to germinate in nature, orchid seeds depend on mycorrhizal fungi to provide them carbohydrate, vitamins and growth factors for germination. The benefit of orchid mycorrhiza can potentially be applied to commercial propagation of orchids. This study compared the effectiveness of five isolates of the orchid mycorrhizal fungus Epulorhiza sp. (= anamorph of Tulasnella) in promoting seed germination and protocorm development of four species of Dendrobium Sw. (Orchidaceae). Orchid seeds sown on Murashige and Skoog (MS) medium, oat meal agar (OMA) or OMA inoculated with one of the five fungal isolates were kept in dark at 25°C for 2 weeks and then in a 16-h-light/8-h-dark cycle for 7 weeks. The promoting effects of different fungal isolates on seed germination of each orchid species were shown to be unequal. The isolates, Da-KP-0-1 and Ps-KT-0-1, were most effective in promoting seed germination and protocorm development of Dendrobium pulchellum Roxb. ex Lindl. and Dendrobium crepidatum Lindl. & Paxton, whereas the isolates Pv-PC-1-1 and Da-KP-0-1 were best for seed germination and protocorm development of Dendrobium findlayanum E.C. Parish & Rchb. f. The seeds of these three orchid species co-cultured with compatible fungi developed more rapidly than asymbiotic seeds of the same species sown on OMA and as rapidly as the ones sown on MS medium. For Dendrobium crystallinum Rchb. f., the average developmental stages of seeds sown on MS medium or OMA inoculated with the most effective fungal isolates were not significantly different from those sown on OMA, probably due to food reserve in the seeds. Randomly sampled protocorms were examined microscopically to confirm the presence of mycorrhizal fungi. All Epulorhiza isolates used in this study, except for the isolate Cs-QS-0-1, could form pelotons in the studied orchids.
•This study reports a simple method for ex vitro symbiotic orchid seed germination.•The method could be successfully used to germinate Spathoglottis plicata.•The method effectiveness was affected by ...fungal isolates and cultivation substrates.•Peat moss with Epulorhiza isolate Da-KP-0-1 was the most effective treatment.•The method can be used by orchid growers with no access to laboratory facilities.
This study reports a simple and efficient method for symbiotic orchid seed germination. Seeds obtained from mature capsules of Spathoglottis plicata Blume were sown non-axenically on common orchid cultivation substrate (i.e., soil, coir dust, or peat moss) pre-inoculated with orchid mycorrhizal fungus, Epulorhiza isolate (=anamorph of Tulasnella; i.e., Da-KP-0-1 or Ps-KT-0-1). Fungal isolates and type of germination substrates were found to affect the effectiveness of this method. At seven weeks after sowing, peat moss inoculated with fungal isolate Da-KP-0-1 was the most effective in promoting seed germination and protocorm development. All other treatments with fungal inoculation yielded significantly higher germination percentages and average developmental stages of seeds/protocorms compared to control treatments. At nine weeks after sowing, protocorms with well-developed leaves and roots could be observed in all inoculation treatments but not in uninoculated controls. Since the established method does not require axenic condition during seed germination step, it should be accessible to professional growers, conservationists, and orchid amateurs alike. Additionally, a potentially antagonistic effect of Epulorhiza against Aspergillus contaminant growing from seeds was observed.
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