Gastrodia Species Research Articles

Gastrodia indica (Orchidaceae: Gastrodieae), a new completely cleistogamous holomycotrophic species from India

Gastrodia indica sp. nov. has been described as a new species from Sikkim, India. This is the first cleistogamous species of the genus Gastrodia discovered from India. It is morphologically allied to G. exilis & G.dyeriana but critical examination revealed considerable differences in floral morphological characters. A detailed taxonomical description along with photoplates, comparison with the allied species and keys for all Gastrodia species from India have been provided to aid in easy identification.

First record of Gastrodia (Orchidaceae, Epidendroideae) from Brunei Darussalam

The occurrence of Gastrodia sabahensis is reported for the first time from Brunei Darussalam representing the new generic record for the country. Morphological description based on the discovered plants along with photo plates, notes on distribution, ecology and conservation status have been provided. Additionally, a determination key for all Gastrodia species in Borneo is presented for the first time.

Gastrodia sikkimensis (Orchidaceae: Gastrodieae), a new holomycotrophic species from Sikkim, India

Gastrodia sikkimensis have been described as a new species from Sikkim, India. It is morphologically allied to G. bawanglingensis and G. theana but critical observation revealed considerable differences in floral morphological characters. A detailed taxonomical description along with photoplates, illustration, comparison with the allied species and keys for all Gastrodia species from India is provided to aid in easy identification.

The study of the tribe Gastrodieae (Orchidaceae, Epidendroideae) in Sri Lanka I: two new species of Gastrodia

As the first step in the taxonomic study of the tribe Gastrodieae (Orchidaceae), two new species, Gastrodia munasinghae and G. thilakapremae are described here from Sri Lanka based on the distinct morphological differences and long-term field observations. Detailed taxonomic descriptions along with the line drawings, color plates, notes on habitat and ecology, distribution and conservation status, phenology and pollination ecology as well as morphological comparison to the other Gastrodia species in Sri Lanka are also discussed. Both species are endemic to the Island and are assessed as Critically Endangered according to the IUCN Red List criteria. Furthermore, notes are provided along with a distribution map for field identification of all Gastrodia species in Sri Lanka.

Transcriptomic heterochrony and completely cleistogamous flower development in the mycoheterotrophic orchid Gastrodia.

Cleistogamy, in which plants can reproduce via self-fertilization within permanently closed flowers, has evolved in > 30 angiosperm lineages; however, consistent with Darwin's doubts about its existence, complete cleistogamy - the production of only cleistogamous flowers - has rarely been recognized. Thus far, the achlorophyllous orchid genus, Gastrodia, is the only known genus with several plausible completely cleistogamous species. Here, we analyzed the floral developmental transcriptomes of two recently evolved, completely cleistogamous Gastrodia species and their chasmogamous sister species to elucidate the possible changes involved in producing common cleistogamous traits. The ABBA-BABA test did not support introgression and protein sequence convergence as evolutionary mechanisms leading to cleistogamy, leaving convergence in gene expression as a plausible mechanism. Regarding transcriptomic differentiation, the two cleistogamous species had common modifications in the expression of developmental regulators, exhibiting a gene family-wide signature of convergent expression changes in MADS-box genes. Our transcriptomic pseudotime analysis revealed a prolonged juvenile state and eventual maturation, a heterochronic pattern consistent with partial neoteny, in cleistogamous flower development. These findings indicate that transcriptomic partial neoteny, arising from changes in the expression of conserved developmental regulators, might have contributed to the rapid and repeated evolution of cleistogamous flowers in Gastrodia.

The extremely reduced, diverged and reconfigured plastomes of the largest mycoheterotrophic orchid lineage

BackgroundPlastomes of heterotrophic plants have been greatly altered in structure and gene content, owing to the relaxation of selection on photosynthesis-related genes. The orchid tribe Gastrodieae is the largest and probably the oldest mycoheterotrophic clade of the extant family Orchidaceae. To characterize plastome evolution across members of this key important mycoheterotrophic lineage, we sequenced and analyzed the plastomes of eleven Gastrodieae members, including representative species of two genera, as well as members of the sister group Nervilieae.ResultsThe plastomes of Gastrodieae members contain 20 protein-coding, four rRNA and five tRNA genes. Evolutionary analysis indicated that all rrn genes were transferred laterally and together, forming an rrn block in the plastomes of Gastrodieae. The plastome GC content of Gastrodia species ranged from 23.10% (G. flexistyla) to 25.79% (G. javanica). The plastome of Didymoplexis pallens contains two copies each of ycf1 and ycf2. The synonymous and nonsynonymous substitution rates were very high in the plastomes of Gastrodieae among mycoheterotrophic species in Orchidaceae and varied between genes.ConclusionsThe plastomes of Gastrodieae are greatly reduced and characterized by low GC content, rrn block formation, lineage-specific reconfiguration and gene content, which might be positively selected. Overall, the plastomes of Gastrodieae not only serve as an excellent model for illustrating the evolution of plastomes but also provide new insights into plastome evolution in parasitic plants.

In-vitro symbiotic germination of seeds of five mycoheterotrophic Gastrodia orchids with Mycena and Marasmiaceae fungi.

We performed in-vitro germination tests on seeds from five Gastrodia orchids (G. confusa, G. elata var. elata, G. elata var. pallens, G. nipponica, and G. pubilabiata) using one Marasmiaceae and two Mycena isolates. Mycena sp. 1 promoted germination of all five Gastrodia orchids, with root and/or tuber formation observed in G. confusa, G. nipponica, and G. pubilabiata. No additional growth was observed in the other two orchids. Mycena sp. 2 induced G. confusa, G. elata var. elata, and G. nipponica germination, whereas Marasmiaceae sp. 1 induced G. nipponica and G. pubilabiata germination. Phylogenetic analyses indicated that the two Mycena isolates represent distinct lineages within the Mycenaceae. Mycena sp. 1 and Marasmiaceae sp. 1 are closely related to Mycena abramsii and Marasmiellus rhizomorphogenus, respectively. Our results imply that Mycena and marasmioid fungi play important roles in early development in Gastrodia species, and that Mycena fungi in particular may be common mycobionts of Gastrodia species. Root and/or tuber development was observed with four plant-fungus combinations, implying that these associations persist throughout the life cycle, whereas G. elata var. elata may require different associates over time. Our findings will contribute to elucidating the mycorrhizal associations of mycoheterotrophic orchids throughout their life cycle.

<strong><em>Gastrodia qingyunshanensis</em> (Orchidaceae: Epidendroideae)—a new holomycotrophic orchid from Guangdong, China</strong>

A new species of Gastrodia (Orchidaceae: Epidendroideae, Gastrodieae), G. qingyunshanensis, is described and illustrated from Guangdong, China. It is closely related to G. appendiculata C. S. Leou & N. J. Chung but can be distinguished by an urceolate (vs bell-like) and dark brown (vs pale greenish brown) perianth tube, the smaller petals (2.5 × 1.6 mm vs 4–5 × 5–6 mm), the shape of lip (oblong, 3×1.6mm vs ovate, 6–7×5mm), lack of elevated calli at the base of petal (vs having calli), and an appendage shorter than column (vs equal to column). The new species is only reported to occur on Qingyunshan Nature Reserve, Wengyuan County, China, and it is proposed to be Vulnerable (VU) according to the IUCN criteria.

New microsatellite markers recognize differences in tandem repeats among four related Gastrodia species (Orchidaceae).

Gastrodia is the most species-rich genus among mycoheterotrophic plants, and is thus an essential taxon to understand the mechanism of species diversification in mycoheterotrophs. In this study, we developed microsatellite markers with high transferability for four Gastrodia species to examine genetic differentiation and similarity among species, populations and individuals. The 12 microsatellite markers developed from a G. fontinalis library showed high transferability for the ramets that identified G. nipponica, G. kuroshimensis and G. takeshimensis. In addition to the high transferability of these markers, we observed low allele variation within a sampled population of each species and allele differences among the four species. The 12 markers described here will be useful for investigating the genetic differences among and within the Gastrodia species, which evolved by a limitation of gene flow.

Gastrodia amamiana (Orchidaceae; Epidendroideae; Gastrodieae), a new completely cleistogamous species from Japan

Gastrodia Brown (1810: 330; Gastrodieae, Epidendroideae) is a mycoheterotrophic leafless genus that is distributed throughout the temperate and tropical regions of Asia, Oceania, Madagascar and Africa (Cribb et al. 2010, Hsu & Kuo 2010, Suetsugu et al. 2018a) and characterized by fleshy tubers, united tepals and two mealy pollinia that lack caudicles (Cribb et al. 2010, Hsu & Kuo 2010, Suetsugu et al. 2018a,b). Several recent studies have re-examined the diversity of Gastrodia in many Asian countries (Hsu et al. 2012, 2016, Ong & O’Byrne 2012, Tan et al. 2012, Suetsugu 2013b, 2014, 2016, 2017, Huang et al. 2015, 2018, Tsukaya & Hidayat 2016, Metusala & Supriatna 2017, Pelser et al. 2016, Suetsugu et al. 2018a,b). As a result, the genus now comprises ca. 100 species, thereby making it the most diverse mycoheterotrophic genus (Hsu et al. 2016, Suetsugu 2017, Suetsugu et al. 2018a,b). However, it is likely that the distribution and diversity of Gastrodia species remain underestimated because plants are easily overlooked in the field due to their short flowering seasons and small size (Hsu et al. 2016, Suetsugu 2017, Suetsugu et al. 2018b).

Gastrodia fujianensis (Orchidaceae, Epidendroideae, Gastrodieae), a new species from China

Gastrodia Brown (1810: 330) (Orchidaceae, Epidendroideae, Gastrodieae) is composed of approximately 90 species with a broad Old World distribution (Pridgeon et al. 2005, Chen et al. 2009, Cribb et al. 2010, Huang et al. 2015, Hsu et al. 2016, Jin et al. 2017, Aung et al. 2018, Suetsugu 2017, Suetsugu et al. 2018). During a survey of native plants in Fujian Province, an unknown species of Gastrodia was collected in August 2018 from the evergreen broad-leaved forest in Wuyishan National Park. A detailed examination of the specimens with similar species morphologically, G. fontinalis Lin (1987: 129), G. major Averyanov (2006: 21), G. punctata Averyanov (2006: 21) and G. huapingensis Huang, Hu & Liu (2015: 290), and two other species recorded from Fujian, G. elata Blume (1856: 174) and G. wuyishanensis Li & Liu (2007: 354), we confirmed it as a new species.

A new species of Gastrodia (Gastrodieae, Epidendroideae, Orchidaceae) from the Maliau Basin Conservation Area, Sabah, Borneo

Gastrodia Brown (1810: 330; Gastrodieae, Epidendroideae) comprises mycoheterotrophic orchids from throughout the temperate and tropical regions of Asia, Oceania, Madagascar and Africa (Chung & Hsu 2006, Cribb et al. 2010, Tan et al. 2012). The genus is characterized by fleshy tubers, as well as the absence of normal leaves, union of sepals and petals and two mealy pollinia that lack caudicles. Furthermore, many Gastrodia species within section Codonanthus (Schlechter 1911, Tuyama 1967) produce inflorescences that are only 3–15 cm in length at flowering (Chung & Hsu 2006) and, owing to their short flowering seasons and dwarf habits, are seldom noticed when flowering (Tuyama 1982, Suetsugu et al. 2012). The identification of Gastrodia species requires detailed observation of floral features, such as lip and column morphology, that are hidden within the perianth tube.

Gastrodia elatoides (Orchidaceae: Epidendroideae: Gastrodieae), a new holomycoheterotrophic orchid from Madagascar

Gastrodia Brown (1810: 330; Gastrodieae, Epidendroideae) is a genus of holomycoheterotrophic orchids distributed from India and eastern Asia through Malaysia to Australia, as well as in tropical Afro-Madagascar (Pearce & Cribb 2002, Kores & Molvray 2005, Chen et al. 2009, Cribb et al. 2010). In this genus, 85 species have been accepted based on the combined information from Govaerts et al. (2018) and recently published new records of Gastrodia species (Jin & Kyaw 2017, Metusala & Supriatna 2017, Suetsugu 2017, Aung & Jin 2018). Consequently, it is now the largest holomycoheterotrophic genus among vascular plants (Hsu et al. 2016, Suetsugu 2017). Gastrodia is characterised by a fleshy tuber or coralloid rhizome, fusion of sepals and petals, a spurless lip and two sectile pollinia (Pearce & Cribb 2002, Kores & Molvray 2005, Chen et al. 2009). One species, G. elata Blume (1856: 174), is a highly valued plant in traditional Chinese medicine (TCM) for the treatment of convulsive disorders such as epilepsy (Cribb et al. 2010, Chen et al. 2009).

Epitypification of Gastrodia pubilabiata (Gastrodieae, Epidendroideae, Orchidaceae)

The genus Gastrodia Brown (1810: 330; Gastrodieae, Epidendroideae) is distributed throughout the temperate and tropical regions of Asia, Oceania, Madagascar, and Africa (Cribb et al. 2010; Govaerts et al. 2016). The genus is characterized by its fleshy tubers, lack of leaves, united sepals and petals, and the production of two mealy pollinia that lack caudicles. Several recent studies have re-examined the diversity of Gastrodia species in various Asian countries (Ong & O’Byrne 2012; Suetsugu 2013, 2014, 2016, 2017; Hu et al. 2014; Huang et al. 2015; Ong 2015; Hsu et al. 2016; Pelser et al. 2016; Tsukaya & Hidayat 2016), and as a result, the genus has been updated to include more than 90 accepted species, thereby making it the most species-rich genus among mycoheterotrophic plants.

Gastrodia bambu (Orchidaceae: Epidendroideae), A New Species from Java, Indonesia

Gastrodia bambu Metusala, a new species of Gastrodia (Orchidaceae: Epidendroideae, Gastrodieae) from Mount Merapi, Yogyakarta Province, Java, Indonesia, is described and illustrated. This new species is morphologically close to Gastrodia abscondita J.J.Sm, but differs in having a larger dark brown flower, a longer perianth tube, ovate petals, a longer and oblong-lanceolate lip, a different shape keels on lip, and a different shape column.

First Record of the Mycoheterotrophic Orchid Gastrodia uraiensis (Orchidaceae) from Yakushima Island, Japan

Flowering individuals of an unknown species of Gastrodia were discovered on Yakushima Island, Japan. While those plants were somewhat similar to gastrodia fontinalis, they had shorter inflorescences,

Two new species of Gastrodia (Gastrodieae, Orchidaceae) endemic to New Zealand

Two new species of Gastrodia, G. cooperae and G. molloyi are described. These species are endemic to New Zealand and can be distinguished from other New Zealand Gastrodia by the length of the column and the colour of the labellum tip. Gastrodia cooperae is known from only three localities and it is ranked as Threatened: Nationally Critical.

A new species of Gastrodia (Orchidaceae: Gastrodieae, Epidendroideae) from Java

Gastrodia Brown (1810: 330) is a mycoheterotrophic genus of Orchidaceae that consists of ca. 50 species (Tan et al. 2012, Suetsugu 2014, Huang et al. 2015). It is characterized by a fleshy tuber or coralloid root system, fused sepals and petals, and two mealy pollinia without caudicles. Since most Gastrodia species have completely fused sepals and petals, observation of the perianth is difficult, and identification of this genus is often imprecise. As a result of re-examination of floral characters, several new taxa in this genus have been reported in China, Taiwan, Japan, Madagascar and other countries during the last decade (Meng et al. 2007, Hsu et al. 2010, Hsu & Kuo 2011, Yeh et al. 2011, Hsu et al. 2012, Tan et al. 2012, Suetsugu 2013, 2014, Huang et al. 2015, Martos et al. 2015). Most of these new taxa belong to the section Codonanthus (Schlechter 1911), which has a short inflorescence (<40 cm).

Embryology of two mycoheterotrophic orchid species, Gastrodia elata and Gastrodia nantoensis: ovule and embryo development.

Background Gastrodia elata, a famous herbal medicine, has been received great attention on its treatments of headache, vertigo and epilepsy. Gastrodia nantoensis is a newly described species from central Taiwan with potential medicinal value. Gastrodia species are fully mycoheterotrophic orchids, and the courses of their seed development are more rapid as compared to the chlorophyllous orchids. A better understanding of their reproductive biology would provide insights into the propagation and conservation of the mycoheterotrophic orchid species.ResultsBased on the histological and histochemical investigations, we observed some notable features in ovule and embryo development. First, only the archesporial cell and/or megasporocyte are present within their ovaries at the time of anthesis. Second, their suspensors consist of a single cell and their mature embryos consist of a gradient of small to large cells. Nile red staining of a globular embryo reveals the presence of cuticular material in the surface wall of embryo proper and the lateral walls of suspensor cell, indicating that the basal wall of suspensor cell is the major route for nutrient supply from maternal tissues to embryo proper. Third, their seed coats are derived from a single integument, and lignin but not cuticular material is present in the outer most layer of seed coat and persists through seed maturation.ConclusionsThe faster seed development of Gastrodia species is due to the speedy courses of ovule and embryo development. In the mature seeds, the presence of a differentiated apical zone in embryo proper suggests the easy-to-germinate character. This study provides basic knowledge for further molecular studies on embryo development and symbiotic germination of Gastrodia species.

Gastrodia cajanoae (Orchidaceae: Epidendroideae: Gastrodieae), a new species from the Philippines

Gastrodia Brown (1810: 330) is a holomycotrophic terrestrial orchid genus of c. 65 species with an Old World distribution and centre of diversity in Southeast Asia (Cribb et al. 2010, Huang et al. 2015, Ong 2015). In the Philippines, two species are thus far known: G. javanica (Blume, 1825: 421) Lindley (1840: 384) and G. verrucosa Blume (1856: 175). Both have a widespread distribution in northern Malesia and southern East Asia. During fieldwork for the Co’s Digital Flora of the Philippine project (Pelser et al. 2011 onwards) in early December 2012, Gastrodia plants were photographed that belong to a third Philippine species. These plants were observed in three areas on the island of Mindanao: Mt. Apo Natural Park (North Cotabato Prov.) and two sites in Mt. Kitanglad Range Natural Park (Lantapan and Baungon municipalities; Bukidnon Prov.). In December 2015, plants belonging to the same species were collected in Northern Negros Natural Park (Victorias City, Negros Occidental Prov., Negros) and in March 2016 plants were photographed in Barlig (Mountain Prov., Luzon). Morphological studies showed that this species is distinct from all Gastrodia species except G. spathulata (Carr, 1935: 180) Wood (in Wood et al. 2011: 355) in having petals that are considerably shorter than the calyx tube and separate from it about half way along the inner surface of the tube. It differs from G. spathulata in the longer adnation of the petals to the calyx tube, the shape of the petals and their lack of indumentum, and characters of the lip ridges. Assuming that these morphological differences are an indication of reproductive isolation, we name and describe these plants here as a new species under a biological species concept (Mayr 2000). This new addition brings the total number of Philippine Gastrodia species to three.