Protocorm Growth Research Articles

Effect of Melatonin on the Growth of Dendrobium officinale Protocorm-Like Bodies

Dendrobium officinale Kimura & Migo is a perennial herbaceous plant of the genus Dendrobium in the family of Orchidaceae with high medicinal value. Melatonin (MT) is an indole-like tryptamine with functions such as regulating plant growth and development. This experiment investigated the effects of different concentrations of MT on the growth and development of protocorms of D. officinale protocorm-like bodies (PLBs). The results showed that the changes in morphological indicators such as color, cluster size, and surface changes were more significant under 75 µM MT than those of 0 µM (CK), and the appearance of white on the PLB surface was expedited, which was more conducive to the proliferation of PLBs. MT treatment of 100 µM inhibited the differentiation of adventitious buds, and the contents of photosynthetic pigments, polysaccharides, and flavonoids were significantly increased. Moreover, as compared with CK, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in PLBs increased significantly, while the content of malondialdehyde (MDA) decreased gradually with 75 µM or less. In conclusion, a concentration of 75 µM melatonin can enhance the rapid propagation rate of D. officinale in vitro, providing insights into the effects of melatonin on the growth of tissue-cultured D. officinale seedlings.

RESPON PERTUMBUHAN PROTOKORM ANGGREK SENDU (Grammatophyllum stapeliiflorum) DENGAN PENAMBAHAN BEBERAPA JENIS PUPUK DAUN SECARA IN VITRO

Indonesia has 26,000 species of orchids that are very potential and profitable. Grammatophllum stapeliiflorum is an orchid species that is increasingly difficult to find in its natural habitat. The addition of foliar fertilizer containing macro and micro nutrients can increase plant growth. The purpose of this study was to determine the effect of foliar fertilizer type, concentration and the combination of the two factors on the growth of the orchid protocorm G. stapeliiflorum. This study used a factorial completely randomized design with two research factors, namely the type of foliar fertilizer with 2 treatment levels, B1 = Gandasil-D and B2 = Growmore. The second factor, fertilizer concentration with 4 treatment levels, namely A0 = control (without foliar fertilizer), A1 = 1 g/L, A2 = 2 g/L, and A3 = 3 g/L. This study consisted of 8 treatment combinations which were repeated 4 times, resulting in 32 experimental units. The parameters observed were the percentage of live explants, the percentage of browning, and the percentage of protocorms growth stages. Data were analyzed by Analysis of Variance (ANOVA) and continued with Duncan's Multiple Range Test (DMRT) at a 5% level. These results indicated that the application of foliar fertilizers with Gandasil-D and Growmore affects the percentage of live explants and protocorm growth phases and also increase the percentage browning until of 32,5%. Gandasil-D is better for protocorm growth from globular to torpedo. The control is better for forming shoot of 22,5% compared to the use of foliar fertilizer.

Symbiotic Culture of Three Closely Related Dendrobium Species Reveals a Growth Bottleneck and Differences in Mycorrhizal Specificity at Early Developmental Stages

Mycorrhizal specificity, i.e., the range of fungi allowing mycorrhizal partnerships, differs among orchid species, but that at early developmental stages is unclear. We investigated whether mycorrhizal specificity during seed germination and seedling development differs among three Dendrobium species, D. officinale, D. okinawense and D. moniliforme, in vitro. Nine mycorrhizal fungal strains were obtained from the roots of these species and cultured with a seed of each Dendrobium species. Five to eight fungal strains stimulated seed germination, whereas one to four fungal isolates significantly promoted protocorm development in the three species. To evaluate effects on leafy seedling growth, seedlings obtained from asymbiotic culture were cultured with nine fungal isolates. D. officinale and D. okinawense showed specificity for a single Serendipitaceae or Tulasnellaceae isolate, whereas D. moniliforme exhibited specificity for three isolates of Serendipitaceae and Tulasnellaceae. Therefore, the three Dendrobium species had a growth bottleneck from seed germination to the protocorm stage, and mycorrhizal specificity of protocorm growth and seedling development in vitro varied among the species. Our findings imply divergent mycorrhizal specificity in Dendrobium species at early developmental stages. This study provides insights into the diversity of orchid mycorrhizal specificity, as well as valuable information for conservation of endangered orchids.

Pemberian air rebusan kentang pada media Murashige-Skoog terhadap pertumbuhan protokorm anggrek sendu (Grammatophyllum stapeliiflorum) secara in vitro

Grammatophyllum stapeliiflorum is one of the most popular orchid species because of its beauty and is characterized by the shape of the flower stalk that sticks down and the brown flowers with white and yellow spots that look like drops of water or sad. This type of orchid is almost extinct and is rarely found in its natural habitat, so it is necessary to perform in vitro propagation of orchids. The culture in vitro method is one of the most effective methods for propagating rare orchids. This study aimed to determine the effect of adding potato water on protocorm growth and determine the best concentration for the growth of G. stapeliiflorum protocorm in vitro. This study used a Completely Randomized Design (CRD) with the addition of potato water (concentrations 0, 50, 100, 150, and 200 ml/L) on Murashige-Skoog (MS) medium. The results showed that the percentage of live explants was 100% in all treatments. The addition of potato water to MS medium had no effect on the percentage of live explants but still affected the growth percentage of Protocorm-like bodies (PLBs) in vitro. The best concentration of potato water for the protocorm growth of G. stapeliiflorum in vitro to MS medium was at a concentration of 150 ml/L, which was indicated by the highest percentage of PLBs growth at 100% and the color of PLBs green (2.5GY 6/8) compared to other potato water treatments and controls.

OPTIMIZATION PARAMETER FOR PRODUCTION OF PROTOCORM-LIKE BODY AND GROWTH OF GRAMMATOPHYLLUM SPECIOSUM

Micropropagation of orchids are often through the production of Protocorm Like Bodies (PLBs) and this research conducted a study to discover the optimal condition for the growth of Protocorm Like Bodies (PLBs) and also plantlets regeneration of Grammatophyllum speciosum Several aspects such as different carbon sources (sucrose, maltose) and the presence of charcoal alongside with the variety of concentration of agar were taken into account for the optimization. This study discovered that the 30 g/L of sucrose in 1 mg/L of BAP was superior in producing heavy PLBs. However, the trend differs in the number of plantlets where maltose (5 g/L) is seen to produce a higher number of plantlets compared to sucrose. Charcoal plays an important role in the growth of PLBs where the heaviest PLBs were recorded in the medium supplemented with 0.20 % of charcoal along with 4.5 g of agar. Vice versa relationship was recorded for the number of plantlets where without charcoal in 4.5 g of agar produce the highest number of plantlets.

Effect of Chitosan, Coconut Water and Potato Extract on Protocorm Growth and Plantlet Regeneration of Cymbidium aloifolium (L.) Sw.

Effective and rapid in vitro plantlet regeneration from protocorms of Cymbidium aloifolium using chitosan, coconut water and potato extract were investigated. Two experiments were performed using twelve week old protocorms of size 2-3 mm. In the first experiment, the protocorms were propagated on solid New Dogashima (ND) medium supplemented with various concentrations of chitosan (0, 0.05, 0.10 and 1.00 mg/l). For the second experiment, the protocorms were cultured on the same medium supplemented with coconut water (0, 100, 150 and 200 ml/l) and potato extract (0, 5, 10 and 15 g/l). Survival and response percentages, shoot number and length, root number and length, leaf number and fresh and dry weight were collected after 10 weeks of culture. The results showed that 0.05 mg/l chitosan treatment was the most effective for protocorm growth, producing the highest shoot number and length, root number and length, leaf number, and fresh and dry weight. The combination of coconut water and potato extract treatments revealed that 150 ml/l coconut water alone was the best for plantlet regeneration and growth, shoot length, root length, and fresh and dry weight. This treatment gave significantly different results from the other treatments. Findings will provide useful information for other in vitro commercial or conservation orchid propagation programs.

Progress and Prospects of Mycorrhizal Fungal Diversity in Orchids.

Orchids form mycorrhizal symbioses with fungi in natural habitats that affect their seed germination, protocorm growth, and adult nutrition. An increasing number of studies indicates how orchids gain mineral nutrients and sometime even organic compounds from interactions with orchid mycorrhizal fungi (OMF). Thus, OMF exhibit a high diversity and play a key role in the life cycle of orchids. In recent years, the high-throughput molecular identification of fungi has broadly extended our understanding of OMF diversity, revealing it to be a dynamic outcome co-regulated by environmental filtering, dispersal restrictions, spatiotemporal scales, biogeographic history, as well as the distribution, selection, and phylogenetic spectrum width of host orchids. Most of the results show congruent emerging patterns. Although it is still difficult to extend them to all orchid species or geographical areas, to a certain extent they follow the “everything is everywhere, but the environment selects” rule. This review provides an extensive understanding of the diversity and ecological dynamics of orchid-fungal association. Moreover, it promotes the conservation of resources and the regeneration of rare or endangered orchids. We provide a comprehensive overview, systematically describing six fields of research on orchid-fungal diversity: the research methods of orchid-fungal interactions, the primer selection in high-throughput sequencing, the fungal diversity and specificity in orchids, the difference and adaptability of OMF in different habitats, the comparison of OMF in orchid roots and soil, and the spatiotemporal variation patterns of OMF. Further, we highlight certain shortcomings of current research methodologies and propose perspectives for future studies. This review emphasizes the need for more information on the four main ecological processes: dispersal, selection, ecological drift, and diversification, as well as their interactions, in the study of orchid-fungal interactions and OMF community structure.

Fungal symbionts may modulate nitrate inhibitory effect on orchid seed germination

Many orchid species are threatened, while some disappear from their natural habitats without obvious reasons. Eutrophication has been suggested as a possible factor and nitrate, which is able to suppress non-symbiotic orchid seed germination even at very low concentrations, and could pose a serious threat for natural orchid populations. Early ontogenesis of all orchids entirely depends on orchid mycorrhizal symbiosis, and at this initial mycoheterotrophic stage, many terrestrial green orchids associate with polyphyletic fungal symbionts (i.e., mycobionts), collectively called "rhizoctonias." We asked whether these fungi might also have some non-nutritional roles, i.e., whether they might confer resistance to eutrophication. To test this hypothesis, we co-cultivated seeds of the terrestrial orchid Dactylorhiza majalis with five rhizoctonias (two Tulasnella, two Ceratobasidium and one Serendipita isolate) at various ecologically meaningful nitrate concentrations (0 to 100mg/L). With the exception of one Tulasnella isolate, all mycobionts supported the growth of protocorms and formed orchid mycorrhiza, i.e., intracellular hyphal pelotons, in the protocorms. Nitrate suppressed asymbiotic, as well as symbiotic, seed germination in all but one fungal treatment; the seeds co-cultivated with one of the Ceratobasidium isolates were indeed insensitive to nitrate. We conclude that nitrates also negatively affect symbiotic orchid germination, depending on the available compatible mycobionts. Thus, eutrophication with nitrate may decrease the number of orchid mycobionts capable of supporting seed germination.

Effects of Media composition on Asymbiotic Seed Culture of Vanda tessellata : An Approach to In vitro Conservation

For initiation of seed germination and protocorm growth in Vanda tessellata (Roxb.) Hook. ex G. Don different media, namely Knudson’s C basal medium, modified Knudson’s C basal medium, Murashige and Skoog basal medium, Vacin and Went basal medium and Lindeman basal medium either alone or supplemented with vitamin or 0.1% peptone (w/v) were used. Vitamin mixture was consisted of nicotinic acid, pyridoxine and thiamine HCl at 1 : 1 : 10, respectively. For the initiation of germination, all the treatments exhibited promising results without showing significant variation. But the rate of survival of the germinated seedlings was remarkably low in all the basal media. Maximum survival rate of germinated seedlings was recorded in MS + 0.1% peptone. Necrosis of protocorms was a common phenomenon in all the treatments and 100% necrosis was recorded in LM basal medium and LM + vitamin. Addition of vitamin mixture and peptone in the basal media increased the rate of survival as well as differentiation of the germinated protocorms. Maximum rooted plantlets were recorded in VW + 0.1% peptone
 Plant Tissue Cult. & Biotech. 30(2): 285-295, 2020 (December)

Asymbiotic Germination, Effect of Plant Growth Regulators, and Chitosan on the Mass Propagation of Stanhopea hernandezii (Orchidaceae)

Background: Stanhopea hernandezii was collected from natural habitat in Mexico for its beautiful fragrant flowers. Biotechnological strategies of propagation may satisfy the market demand and are useful for conservation programs.
 Hypothesis: Vigorous seedlings of S. hernandezii can be produced in vitro by asymbiotic seed germination techniques and the addition of chitosan to the culture medium in the temporary immersion system (RITA®) and in semi-solid medium systems.
 Methods: The first step was the in vitro germination of seeds obtained from a mature capsule of wild plants, followed by multiplication via adventitious protocorm induction known as protocorm-like bodies, using plant growth regulators. For this purpose, we utilized Murashige and Skoog (MS) basal medium amended with 0.5 mg/L ?-Naphthaleneacetic acid, combined with different concentrations of 6-Benzylaminepurine (1, 3, and 5 mg/L). The following step comprised the growth and development of protocorms to obtain plantlets in RITA® flasks containing 250 mL of liquid MS medium combined or not with different chitosan concentrations (5, 10, 15, 20, and 25 mg/L).
 Results: The results showed that media supplemented with 5, 10, and 15 mg/L chitosan concentrations enabled the obtaining of a larger biomass with a range of 40-48 seedlings/RITA® and an average height of 13 mm. The last step was the development from seedlings into plantlets, the latter being, vigorous and achieving up to 100 % survival after 12 weeks of ex vitro cultivation.
 Conclusion: This paper describes an efficient process of asymbiotic germination and mass propagation of S. hernandezii , a vulnerable orchid species endemic to Mexico.

Mycorrhizal Fungi Isolated from Native Terrestrial Orchids from Region of La Araucanía, Southern Chile.

Mycorrhizal interactions of orchids are influenced by several environmental conditions. Hence, knowledge of mycorrhizal fungi associated with orchids inhabiting different ecosystems is essential to designing recovery strategies for threatened species. This study analyzes the mycorrhizal associations of terrestrial orchids colonizing grassland and understory in native ecosystems of the region of La Araucanía in southern Chile. Mycorrhizal fungi were isolated from peloton-containing roots and identified based on the sequence of the ITS region. Their capacities for seed germination were also investigated. We detected Tulasnella spp. and Ceratobasidium spp. in the pelotons of the analyzed orchids. Additionally, we showed that some Ceratobasidium isolates effectively induce seed germination to differing degrees, unlike Tulasnella spp., which, in most cases, fail to achieve protocorm growth. This process may underline a critical step in the life cycle of Tulasnella-associated orchids, whereas the Ceratobasidium-associated orchids were less specific for fungi and were effectively germinated with mycorrhizal fungi isolated from adult roots.

Relative effectiveness of Tulasnella fungal strains in orchid mycorrhizal symbioses between germination and subsequent seedling growth

Orchids rely strictly on mycorrhizal symbioses for nutrition, including carbon, from seed germination to protocorm growth. However, whether orchids establish symbiotic compatibility selectively with specific mycorrhizal fungi during this early growth period remains to be determined for most species. We examined pair-wise symbiotic compatibility between three terrestrial orchid species, Bletilla striata, Pecteilis radiata, and Spiranthes australis, and five closely related strains of Tulasnella, using a procedure we recently developed for detailed and quantitative evaluation of mycorrhizal symbiosis during post-germination growth. Our analyses revealed significant differences among colonization effects of the Tulasnella strains on the hosts, both at seed germination and during post-germination growth. The effects of the mycorrhizal associations tended to differ by stage, suggesting a variety of determinants for symbiotic compatibility. One Tulasnella strain exhibited high compatibility across the three distantly related host species, implying that inherent properties of mycorrhizal fungi can influence their symbiotic compatibility with a wide range of orchid species.

Medium composition, coconut water, and chitosan effects on Phalaenopsis protocorm growth and development

Medium composition, coconut water, and chitosan effects on <i>Phalaenopsis</i> protocorm growth and development

Pengaruh Konsentrasi Zat Pengatur Tumbuh Naphthalene Acetic Acid dan Benzil Amino Purin terhadap Pertumbuhan Protokorm Anggrek Dendrobium spectabile pada Kultur In Vitro

The aim of the article is to study the interaction effect between NAA and BAP concentration on protocorm growth and to know the proper concentration for growth of Dendrobium spectabile orchid protocorm. This research method using an experimental method which is conducted in the Laboratory of Agriculture Faculty of Winaya Mukti University, Tanjungsari Subdistrict, Sumedang District. The experiment was conducted from June 2017 until September 2017. The experiment used was a Completely Randomized Design (CRD) with the factorial pattern, consisting of two factors and repeated twice. the first factor was the effect of NAA concentration which consisted of five levels, namely without NAA, 0.5 mg kg-1, 1.0 mg kg-1, 1.5 mg kg-1, and 2.0 mg kg-1. The second factor is the BAP concentration which consists of five levels, namel without BAP, 1.0 mg kg-1, 2.0 mg kg-1, 3.0 mg kg-1, and 4.0 mg kg-1. Eksplant is protocorm from orchid D. spectabile which is grown on MS medium (Murashig and Skoog) half recipe as base medium accompanied by each treatment for 12 weeks. The experimental results show that there is an interaction between the effect of NAA and BAP concentration on the number of leaves only. Without NAA or 1.5 mg kg-1 NAA concentration with BAP 2.0 mg kg-1 gives more leaves. Independent of NAA or BAP concentrations did not affect the number of buds, number of roots, root length, fresh and dry weight of plantlets, and also growth ability of plantlets. BAP concentration only affect plant height, and the highest plantlet height is found without add of BAP in medium culture

PENGARUH PEPTON TERHADAP PERTUMBUHAN EMBRIO ANGGREK &lt;em&gt;Vanda tricolor&lt;/em&gt; Lindley var. Suasiv ASAL MERAPI SECARA IN VITRO

Orchidaceae is a valuable ornamental plant in Indonesia’s export commodities. The growth of orchid in nature is prolonged due to its microscopic size of the seed and has no endosperm. In the mass-production, an inducer is required to accelerate the growth in an in-vitro culture, one of which is peptone. The embryos used in this study is Merapi endemic orchid, the Vanda tricolor Lindley var. Suavis. This study aimed to determine the effect of peptone on the growth of eight weeks old of Vanda tricolor Lindley var. Suavis embryos and to determine the optimal peptone concentration to induce the growth of the orchid embryo. This experiment was conducted in the Biotechnology Laboratory of the Faculty of Biology Universitas Gadjah Mada from September to October 2016. The treatments applied in this study was a variety of peptone concentrations (0–3 g/L) in growth media to induce eight weeks old protocorm subcultures. The study measured the morphological development of protocorm to determine the effect. The results showed a positive effect of peptone on the growth of orchid embryos at the NP1 treatment concentration of 1 g/L. The growth reached the phase 6 with the rate measured about 6.85±0.001% in the fourth week. This value was higher than the protocorm growth rate when it reached the phase 6 in the fourth week on the NP0 medium measured at 5.22±0.003%, on the medium NP2 at 1.15±0.002%, and on the medium NP3 at 1.02±0.001%. This result showed the effect of peptone concentration to induce the growth of Vanda tricolor Lindley var. Suavis embryo, but the excess concentration of peptone inhibited the growth of protocorm.

Utilization of exogenous saccharides by protocorms of two terrestrial orchids

Orchid protocorms are completely mycoheterotrophic structures. Although saccharides are proposed as the main energy and carbon (C) sources provided by fungi, there is only limited knowledge on their effects. For the first time, utilization of a wide range of saccharides by in vitro axenic protocorms of two terrestrial orchids from two subfamilies, Ophrys iricolor subsp. lojaconoi and Oeceoclades, was tested. Protocorm size and, in the first of these also rhizoid length and soluble saccharide contents, were analysed. The endogenous saccharide spectra reflected the supplied saccharides and their metabolism. In both species, sucrose supported protocorm growth best. Surprisingly, fructose inhibited O. iricolor subsp. lojaconoi protocorm growth while O. decaryana ones grew well on it. Interestingly, mannitol abundant in mycorrhizal fungi was not utilized while sorbitol not found in fungi was usable. Galactose was toxic at pre-germination stage. Protocorm rhizoid length correlated with protocorm size but revealed several signalling effects of some saccharides. In conclusion, the orchid’s ability to utilize various saccharides reflects more likely species life strategy rather than phylogenetic relations or saccharide abundance in mycorrhizal fungi.

Quantitative evaluation of protocorm growth and fungal colonization in Bletilla striata (Orchidaceae) reveals less-productive symbiosis with a non-native symbiotic fungus

BackgroundIn nature, orchid plants depend completely on symbiotic fungi for their nutrition at the germination and the subsequent seedling (protocorm) stages. However, only limited quantitative methods for evaluating the orchid–fungus interactions at the protocorm stage are currently available, which greatly constrains our understanding of the symbiosis. Here, we aimed to improve and integrate quantitative evaluations of the growth and fungal colonization in the protocorms of a terrestrial orchid, Blettila striata, growing on a plate medium.ResultsWe achieved both symbiotic and asymbiotic germinations for the terrestrial orchid B. striata. The protocorms produced by the two germination methods grew almost synchronously for the first three weeks. At week four, however, the length was significantly lower in the symbiotic protocorms. Interestingly, the dry weight of symbiotic protocorms did not significantly change during the growth period, which implies that there was only limited transfer of carbon compounds from the fungus to the protocorms in this relationship. Next, to evaluate the orchid–fungus interactions, we developed an ink-staining method to observe the hyphal coils in protocorms without preparing thin sections. Crushing the protocorm under the coverglass enables us to observe all hyphal coils in the protocorms with high resolution. For this observation, we established a criterion to categorize the stages of hyphal coils, depending on development and degradation. By counting the symbiotic cells within each stage, it was possible to quantitatively evaluate the orchid-fungus symbiosis.ConclusionsWe describe a method for quantitative evaluation of orchid-fungus symbiosis by integrating the measurements of plant growth and fungal colonization. The current study revealed that although fungal colonization was observed in the symbiotic protocorms, the weight of the protocorm did not significantly increase, which is probably due to the incompatibility of the fungus in this symbiosis. These results suggest that fungal colonization and nutrition transfer can be differentially regulated in the symbiosis. The evaluation methods developed in this study can be used to study various quantitative aspects of the orchid-fungus symbiosis.

Effects of altering medium strength and sucrose concentration onin vitrogermination and seedling growth ofCypripedium macranthosSw.

The genus Cypripedium, known as lady's slipper orchid, has been considered to have a considerable marketability as a potted and garden plant with beautiful flowers; however, this species is becoming endangered and, in some places extinct, due to habitat destruction and illegal collections. As such, an optimized artificial propagation system is necessary for its conservation and horticultural cultivation. For the establishment of the in vitro proliferation of the endangered Cypripedium macranthos Sw., native to Korea, the effects of medium strength and sucrose concentrations on germination, protocorm formation and seedling growth were investigated through asymbiotic seed culture. The highest germination rate and protocorm formation rate were obtained with a 1/4 MS medium; higher MS medium strengths did not generate the favorable conditions required for germination and protocorm growth. The overall growth characteristics of roots and buds developed from protocorms were best in cultures of 1/4 MS medium. On this medium containing 10 g·L -1 sucrose, both the germination rate and protocorm formation rate increased significantly. The general growth properties of seedlings developed on the medium with 10 g·L -1 sucrose were best, showing the highest bud formation rate and root number. Our results demonstrate that the 1/4 MS medium, supplemented with 10 g·L -1 sucrose, could improve in vitro germination, and facilitate the growth of seedlings developed from the protocorms of C. macranthos Sw.

Aplicación de visión por computadora en la evaluación del desarrollo in vitro de protocormos de Oncidium sphacelatum Lindl., (Orchidaceae)

&lt;p&gt;Se presenta una aplicación de visión por computadora diseñada para monitorear el desarrollo de protocormos de orquídea en condiciones &lt;em&gt;in vitro&lt;/em&gt;, con el objetivo de evaluar el proceso de germinación de manera eficiente, rápida y objetiva. A partir de fotografías digitales, se evaluó el desarrollo de protocormos de &lt;em&gt;Oncidium sphacelatum&lt;/em&gt; Lindl. (Orchidaceae) en términos de tamaño (medido a través de su área en pixeles), el cambio de etapa fenológica dentro del proceso de germinación (medido a través del factor de redondez) y el estado de salud (por tonalidad de color). La programación desarrollada para que el ordenador sea capaz de este tipo de análisis, se compone de una etapa de segmentación para discernir los pixeles de interés (protocormos) del fondo, una de entrenamiento-aprendizaje para establecer criterios de segregación y una última de clasificación. La programación se realizó mediante la plataforma Matlab R2012a. Las características obtenidas por el sistema permiten proporcionar de manera automática, digerida y objetiva, información útil para la evaluación del proceso de germinación de las orquídeas en condiciones in vitro, con un significativo ahorro en termino de horas/trabajo y desgaste físico del operador humano, sin perturbar la calidad de la evaluación.&lt;/p&gt;

Proteomic and morphometric study of the in vitro interaction between Oncidium sphacelatum Lindl. (Orchidaceae) and Thanatephorus sp. RG26 (Ceratobasidiaceae).

Orchidaceae establish symbiotic relationships with fungi in the Rhizoctonia group, resulting in interactions beneficial to both organisms or in cell destruction in one of them (pathogenicity). Previous studies have focused mostly on terrestrial species with a few, preliminary studies, on epiphytes. To further our understanding of the molecular mechanisms involved in these symbioses, we evaluated the interaction between Oncidium sphacelatum Lindl. and the mycorrhizal fungus Thanatephorus sp. strain RG26 (isolated from a different orchid species) in vitro using morphometric and proteomic analyses. Evidence from the morphometric and microscopic analysis showed that the fungus promoted linear growth and differentiation of orchid protocorms during 98days interaction. On day 63, protocorm development was evident, so we analyzed the physiological response of both organisms at that moment. Proteome results suggest that orchid development stimulated by the fungus apparently involves cell cycle proteins, purine recycling, ribosome biogenesis, energy metabolism, and secretion that were up-regulated in the orchid; whereas in the fungus, a high expression of proteins implicated in stress response, protein-protein interaction, and saccharides and protein biosynthesis were found in the symbiotic interaction. This is the first work reporting proteins differentially expressed in the epiphytic orchid-fungus interaction and will contribute to the search for molecular markers that will facilitate the study of this symbiosis in both wild orchids and those in danger of extinction.