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Understanding the nutritional ecology of orchids, particularly those in symbiosis with rhizoctonias, presents a complex challenge. This complexity arises partly from the absence of macroscopic fruit bodies in rhizoctonias, which impedes the acquisition of their stable isotope data. In this study, we investigated the fungal associations and isotopic signatures in the pelotons of Stigmatodactylus sikokianus (associated with non-ectomycorrhizal [non-ECM] rhizoctonias) and Chamaegastrodia shikokiana (associated with ECM rhizoctonias). Our research reveals elevated levels of 13 C enrichment in S. sikokianus plants and their pelotons, similar to those found in fully mycoheterotrophic orchids and their mycobionts. Interestingly, C. shikokiana plants and their pelotons exhibited even higher levels of 13 C and 15 N enrichment than many other fully mycoheterotrophic species. Our findings imply that both ECM and saprotrophic mycobionts, including certain rhizoctonias, can fulfill the carbon needs of highly mycoheterotrophic orchids. This finding also indicates that 13 C enrichment can be an indicator of mycoheterotrophy in at least some rhizoctonia-associated orchids, despite the typically low 13 C enrichment in non-ECM rhizoctonias. Our demonstration of partial mycoheterotrophy in S. sikokianus suggests a broader prevalence of this nutritional strategy among orchids, given that almost all orchids are associated with non-ECM rhizoctonias., (© 2024 John Wiley & Sons Ltd.)

Cyrtosia septentrionalis, an orchid species, is notable for its sausage-shaped red fleshy fruits, which can reach up to 10 cm in length. Previous research identified frugivorous and omnivorous birds, especially the brown-eared bulbul Hypsipetes amaurotis (Pycnonotidae, Passeriformes), as key seed dispersers of C. septentrionalis in natural habitats. This finding challenges conventional belief that orchid seeds are primarily wind-dispersed. Moreover, given the rarity of specialized co-evolutionary relationships between fruits and frugivores, C. septentrionalis may also rely on mammals for seed dispersal in certain regions. We aimed to explore the fruit consumption habits of animals other than birds. Motion sensor-equipped cameras were used to observe interactions with the fruits of C. septentrionalis and assess the viability of seeds post-consumption. The observations revealed three animal species consuming the fruits, with the masked palm civet Paguma larvata (Viverridae, Carnivora) identified as a dominant consumer in the investigated population. Microscopy analysis of seeds retrieved from P. larvata faeces indicated that the seeds remained intact and viable after passing through the digestive system of this carnivorous mammal. The above discovery suggests a potential role for carnivorous mammals in seed dispersal of C. septentrionalis, alongside birds, thus broadening our understanding of the complex seed dispersal strategies employed by orchids., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

While most flowering plants engage in mutualistic interactions with their pollinators, Arisaema species employ a unique, seemingly antagonistic strategy by imprisoning and causing the pollinators to perish within their spathes. Recent studies have revealed that Arisaema thunbergii primarily relies on a fungus gnat, Leia ishitanii, with some individuals possibly escaping female spathes after oviposition. We investigated interactions between A. urashima and its pollinating fungus gnats, given that A. urashima is closely related to A. thunbergii. Specifically, we tested whether decaying A. urashima serve as brood-sites for some pollinators and whether these pollinators can escape seemingly lethal floral traps. We retrieved A. urashima spathes together with adult insect corpses trapped within the spathes and incubated the spathes to see if conspecific insects emerged. In addition, under laboratory conditions, we observed the escape behaviour of Sciophila yokoyamai, whose next-generation adults most frequently emerge from the decaying spathes. Our findings indicate that S. yokoyamai almost always escapes from the female spathe after oviposition while using the inflorescence as a nursery. In contrast, other pollinators of A. urashima, including Mycetophila spp., remain trapped and perished within the spathes. This study demonstrates that A. urashima spathes can function both as lethal traps and mutualistic nurseries, with outcomes differing among pollinator species. Our results also suggest that the contribution of certain pollinators to Arisaema reproduction is underestimated or even neglected, given that information on their pollinator assemblages has been based on floral visitors trapped within the inflorescences., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

To evaluate the nutritional modes of orchids associated with 'rhizoctonia' fungi, analyses of hydrogen (δ 2 H), carbon (δ 13 C), and nitrogen (δ 15 N) stable isotope ratios are usually adopted. However, previous studies have not fully accounted for exchangeable hydrogens, which could affect these evaluations. Here, we performed standard δ 13 C, δ 15 N, and δ 2 H analyses on bulk samples. Additionally, we conducted δ 2 H analysis on α-cellulose and cellulose nitrate samples to investigate whether the heterogeneity of exchangeable hydrogens among plant species influences the assessment of nutritional modes. The δ 2 H of orchids were consistently higher than those of surrounding autotrophic plants, irrespective of the three pretreatments. Although the rhizoctonia-associated orchid exhibited lower δ 13 C, its δ 2 H was higher than those of the autotrophs. Notably, among all response variables, δ 15 N and δ 2 H exhibited high abilities for discriminating the nutritional modes of rhizoctonia-associated orchids. These results indicate that a time-efficient bulk sample analysis is an effective method for evaluating plant nutritional modes, as the heterogeneity of exchangeable hydrogens does not significantly impact the estimation. Using δ 15 N and δ 2 H benefits the assessment of partial mycoheterotrophy among rhizoctonia-associated orchids., (© 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.)

Although the absence of normal leaves is often considered a sign of full heterotrophy, some plants remain at least partially autotrophic despite their leafless habit. Leafless orchids with green stems and capsules probably represent a late evolutionary stage toward full mycoheterotrophy and serve as valuable models for understanding the pathways leading to this nutritional strategy. In this study, based on molecular barcoding and isotopic analysis, we explored the physiological ecology of the leafless orchid Eulophia zollingeri, which displays green coloration, particularly during its fruiting phase. Although previous studies had shown that E. zollingeri, in its adult stage, is associated with Psathyrellaceae fungi and exhibits high 13 C isotope signatures similar to fully mycoheterotrophic orchids, it remained uncertain whether this symbiotic relationship is consistent throughout the orchid's entire life cycle and whether the orchid relies exclusively on mycoheterotrophy for its nutrition during the fruiting season. Our study has demonstrated that E. zollingeri maintains a specialized symbiotic relationship with Psathyrellaceae fungi throughout all life stages. However, isotopic analysis and chlorophyll data have shown that the orchid also engages in photosynthesis to meet its carbon needs, particularly during the fruiting stage. This research constitutes the first discovery of partial mycoheterotrophy in leafless orchids associated with saprotrophic non-rhizoctonia fungi., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Letermovir is a newly developed antiviral agent used for the prophylaxis of human cytomegalovirus infections in patients undergoing allogeneic hematopoietic cell transplantation. This novel anti-cytomegalovirus drug, used for the prophylaxis of cytomegalovirus reactivation until approximately 200 days after transplantation, effectively reduces the risk of clinically significant cytomegalovirus infection. No human counterpart exists for the terminase complex; letermovir is virus specific and lacks some toxicities previously observed with other anti-cytomegalovirus drugs, such as cytopenia and nephrotoxicity. The absolute bioavailability of letermovir in healthy individuals is estimated to be 94% based on a population-pharmacokinetic analysis. In contrast, oral administration of letermovir to patients undergoing hematopoietic cell transplantation results in lower exposure than that in healthy individuals. Renal or hepatic impairment does not influence the intrinsic clearance of letermovir. Co-administration of letermovir may alter the plasma concentrations of other drugs, including itself, as it acts as a substrate and inhibitor/inducer of several drug-metabolizing enzymes and transporters. In particular, attention should be paid to the drug-drug interactions between letermovir and calcineurin inhibitors or azole antifungal agents, which are commonly used in patients undergoing hematopoietic cell transplantation. This article reviews and summarizes the clinical pharmacokinetics and pharmacodynamics of letermovir, focusing on patients undergoing hematopoietic cell transplantation, healthy individuals, and specific patient subsets., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Oceanic islands offer valuable natural laboratories for studying evolution. The Izu Islands, with their recent geological origin, provide an exceptional opportunity to explore the initial evolution on oceanic islands. Another noteworthy aspect is the absence of bumblebee species on most Izu Islands. We used ecological, morphological, and molecular data to investigate the impact of bumblebee absence on the evolution of two closely related orchid species, Goodyera henryi and Goodyera similis, focusing on Kozu Island, the Izu Islands. Our investigation revealed that while G. henryi exclusively relies on a bumblebee species for pollination on the mainland, G. similis is pollinated by scoliid wasps on both the mainland and the island. Intriguingly, all specimens initially categorized as G. henryi on Kozu Island are hybrids of G. henryi and G. similis, leading to the absence of pure G. henryi distribution on the island. These hybrids are pollinated by the scoliid wasp species that also pollinates G. similis on the island. The absence of bumblebees might result in sporadic and inefficient pollination of G. henryi by scoliid wasps, consequently promoting hybrid proliferation on the island. Our findings suggest that the absence of bumblebees can blur plant species boundaries., (© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.)

Background: Posaconazole (PCZ) plays a crucial role in the prophylaxis and treatment of invasive fungal infections in hematologic malignancies. PCZ concentrations reportedly vary among patients receiving delayed-release tablets (DRT). However, the factors influencing these concentrations remain insufficiently elucidated. Therefore, this study aimed to evaluate the factors influencing PCZ concentrations and their effect on the probability of target attainment (PTA) using a population pharmacokinetic (PPK) approach. We also explored the relationship between PCZ exposure and hepatotoxicity., Methods: This retrospective study included adult patients with hematologic malignancies who received PCZ DRT. A PPK model was developed based on observational data for 130 concentrations in 28 patients. Simulation analyses were performed to assess the PTA at standard doses of 0.7 and 1.0 mg/L for prophylaxis and treatment, respectively. Estimated concentrations were used to evaluate the correlation between PCZ exposure and hepatotoxicity., Results: Significant factors influencing PCZ concentrations included body weight, serum total protein levels, and diarrhea. Diarrhea correlated with decreased PCZ concentrations resulting in up to 26% lower PTA compared with that without diarrhea. Moreover, PTA declined markedly as the total protein levels decreased from 6.6 g/dL to 4.4 g/dL. The incidence of hepatotoxicity was 17.4% (4/23); no significant relationship could be established between the PCZ concentrations and hepatotoxicity ( P = 0.188)., Conclusions: We identified the factors affecting PCZ exposure, which could not be detected by PPK analysis using data from clinical trials. Our results suggest that the generally recommended dose of PCZ causes underexposure in patients with hematologic malignancies characterized by high body weight, hypoproteinemia, or concurrent diarrhea. Therapeutic drug monitoring for DRT may be recommended, especially in patients with these risk factors., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background/aim: Rash is a common adverse event (AE) observed during cytarabine and idarubicin induction therapy in patients with acute myeloid leukemia (AML). Previous studies have highlighted the challenge in predicting the onset and duration of rash. This study aimed to determine the factors that affect the onset of rash in patients receiving induction therapy for AML., Patients and Methods: This retrospective study involved 97 patients with AML who received induction chemotherapy with cytarabine and idarubicin at the Department of Hematology, Kyushu University Hospital between January 2008 and June 2022. The factors associated with rash were identified through a multivariate stepwise logistic regression analysis. Subsequently, the patient's characteristics were compared between those with risk factors and those without risk factors using a matched pair analysis., Results: Pre-existing leukopenia [odds ratio (OR)=3.294; 95% confidence interval (CI)=1.272-8.531] and good performance status (PS=0) (OR=2.717; 95%CI=1.087-6.792) were significant risk factors for rash development. Conversely, the matched pair analysis indicated that patients with pre-existing leukopenia, excluding those with a PS score of 0, exhibited a significantly (p=0.015) higher incidence of rash than those without it., Conclusion: Both multivariate logistic regression analysis and matched pair analysis identified pre-existing leukopenia as a primary risk factor for rash development associated with cytarabine and idarubicin chemotherapy., Competing Interests: The Authors declare that they have no conflicts of interest in relation to this study., (©2024 The Author(s). Published by the International Institute of Anticancer Research.)

Gentiana zollingeri is an annual photosynthetic plant that employs a mycoheterotrophic growth strategy during its underground seedling stage (initial mycoheterotrophy). Notably, the morphological characteristics of its flowering shoots, such as shoot size, leaf size, and leaf color, are highly variable, and it was hypothesized that these variations may be linked to nutritional mode. The morphological characteristics of G. zollingeri individuals were thus investigated alongside environmental factors, 13 C abundance, and diversity of colonizing arbuscular mycorrhizal (AM) fungi. The majority of G. zollingeri flowering individuals were found to exhibit a high affinity for the specific AM fungi that exclusively colonize roots of the mycoheterotrophic seedlings, while other phylogenetically diverse AM fungi could also be detected. The leaves to shoot dry weight ratio (leaf ratio) was negatively correlated with the canopy openness in the habitat, suggesting that leaf development is impeded in sunny conditions. Furthermore, the shoot weight of G. zollingeri was positively correlated with leaf 13 C abundance. Given that 13 C enrichment can provide indirect evidence of mycoheterotrophy in AM plants, the results suggest that the utilization of carbon obtained through mycoheterotrophy, at least during the underground seedling stage, is crucial for G. zollingeri., (© 2023. The Author(s) under exclusive licence to The Botanical Society of Japan.)

The systematics of the Old World Spiranthes sinensis (Pers.) Ames species complex (Orchidaceae) has been complicated by its wide distribution and morphological variations. Within the species complex, S. australis Lindl. has been generally accepted as the only Spiranthes Rich. species distributed on the Japanese mainland. The present study provides morphological, phylogenetic, and ecological evidence for the recognition of S. hachijoensis Suetsugu as a new species of the S. sinensis species complex on the Japanese mainland. Spiranthes hachijoensis is morphologically similar to S. hongkongensis S.Y. Hu & Barretto and S. nivea T.P. Lin & W.M. Lin, sharing a degenerated rostellum, pollinia without a viscidium, and distinctly trilobed stigma. However, the taxon can be morphologically distinguished from S. hongkongensis by its glabrous rachis, ovaries, and sepals, and from S. nivea by its papillate labellum disc, larger papillate basal labellum callosities, and glabrous rachis, ovaries, and sepals. The autogamy and flowering phenology (i.e., earlier flowering) of S. hachijoensis are most likely responsible for premating isolation from the sympatric S. australis. A MIG-seq-based high-throughput molecular analysis indicated that the genetic difference between S. hachijoensis and its putative sister species S. sinensis is comparable to, or even greater than, the genetic difference between pairs of other species within the S. sinensis species complex. Our multifaceted approach strongly supports the recognition of S. hachijoensis as a morphologically, phenologically, phylogenetically, and ecologically distinct species., (© 2023. The Author(s).)

Background: Pharmacists should be aware of their thought processes in dispensing work, including differences in the dispensing complexities owing to different drug positions in the left, center, and right areas. Dispensing errors associated with "same-name drugs (a pair of drugs with the same name but a different ingredient quantity)" are prevalent and often negatively affect patients. In this study, using five pairs of comparative models, the gaze movements of pharmacists in dispensing work were analyzed using an eye-tracking method to elucidate their thought processes., Methods: We prepared verification slides and displayed them on a prescription monitor and three drug rack monitors. The dispensing information (drug name, drug usage, location display, and total amount) was displayed on a prescription monitor. A total of 180 drugs including five target drugs were displayed on the three drug rack monitors. Total gaze points in the prescription area, those in the drug rack area, total vertical movements between the two areas, and time required to dispense drugs were measured as the four classifications Gaze 1, Gaze 2, Passage, and Time, respectively. First, we defined the two types of location displays as "numeral combination" and "color/symbol combination." Next, we defined two pairs of models A 1 -A 2 (numerals) and B 1 -B 2 (color/symbol) to compare differences between the left and right areas. Moreover, three pairs of models C 1 -C 2 (left), D 1 -D 2 (center), and E 1 -E 2 (right) were established to compare differences between "numeral combination" and "color/symbol combination.", Results: Significant differences in the complexities of dispensing work were observed in Gaze 2, Passage, and Time between the models A 1 -A 2 (A 1 2 ), in Gaze 2 between the models B 1 -B 2 (B 1 >B 2 ), and in Gaze 2 and Time between the models C 1 -C 2 , D 1 -D 2 , and E 1 -E 2 (C 1 >C 2 , D 1 >D 2 , and E 1 >E 2 , respectively)., Conclusions: Using the current dispensing rules, pharmacists are not good at dispensing drugs located in the right area. An effective measure for reducing the dispensing complexity is to introduce visual information in the prescription content; the utilization of the right brain facilitates reducing the complexity in the right dispensing area., (© 2024. The Author(s).)

The family Thismiaceae, known as "fairy lanterns" for their urn- or bell-shaped flowers with basally fused tepals, consists of non-photosynthetic flowering monocots mainly in tropical regions, extending into subtropical and temperate areas. Here, we propose a new mycoheterotrophic genus, Relictithismia Suetsugu & Tagane (Thismiaceae), with its monotypic species Relictithismia kimotsukiensis Suetsugu, Yas.Nakam. & Tagane from Kimotsuki Mountains in the Osumi Peninsula, Kagoshima Prefecture, Kyushu Island, southern Japan. Relictithismia resembles Haplothismia Airy Shaw in having a cluster of tuberous roots, a feature previously observed only in this genus within the family Thismiaceae. However, it differs in having solitary flowers (vs. 2-6-flowered pseudo-raceme in Haplothismia), anther thecae largely separated (vs. connate), and the presence of an annulus (vs. absent). Additionally, Relictithismia differs from the geographically overlapping genus Thismia Griff. in its stamen structure and the position of the annulus. In Relictithismia, the stamens lack connectives, and its free filaments arise from the annulus located inside the perianth mouth, while in Thismia, the stamens typically have connate connectives, forming a staminal tube pendulous from the annulus located at the mouth of the floral tube. Our morphological and phylogenetic data indicated that R. kimotsukiensis holds an early-diverging position within the family, situated outside the Old World Thismia clade. This paper offers an extensive description and color photographs of R. kimotsukiensis, complemented by notes on its phylogenetic relationship and evolutionary history., (© 2024. The Author(s).)

Metal-organic frameworks (MOFs) are promising materials because of their high designability of pores and functionalities. Especially, MOF thin films and their properties have been investigated toward applications in nanodevices. Typically, MOF thin films are fabricated by using a bottom-up method such as layer-by-layer (LbL) growth in air. Because the water molecules can coordinate and be replaced with organic linkers during synthesis, humidity conditions will be expected to influence the LbL growth processes. In this study, we fabricated MOF thin films composed of Zn 2+ , tetrakis-(4-carboxyphenyl)-porphyrin (TCPP), and 4,4'-bipyridyl (bpy) at 10 and 40% relative humidity (RH) conditions. Then, we investigated the humidity effects on chemical compositions of TCPP and bpy, periodic structure, orientation, and surface morphology. At high RH, coordination replacement of water with the organic linkers becomes more competitive than that at low RH, resulting in a different TCPP/bpy composition ratio between the two RH conditions. Also, more frequent coordination replacements of water with the organic linkers at high RH led to the formation of phases other than that observed at low RH, loss of growth orientation, and rough surface. The findings clarified the importance of controlling the RH condition during LbL growth to obtain the desired coordination networks.

The degree of specificity between fully myco-heterotrophic (MH) orchids and mycorrhizal fungi is regarded as high, but some species undergo a mycobiont shift as they transition from juvenile to adult plant. We investigated morphological and physiological aspects of the interaction between the fully MH Cyrtosia septentrionalis and its four known mycobionts to elucidate developmental consequences of variable, life-stage-dependent specificity. Of five randomly sampled germinated seeds co-cultured with each mycobiont, Physisporinus sp. ' TK-10 ' colonized all, Armillaria gallica and Desarmillaria tabescens colonized one, and A. mellea subsp. nipponica colonized none. Whereas 16.2% of aseptically germinated seeds exhibited onward growth when co-cultured with TK-10 , just 1.5-2.6% did so with the other species. Even so, A. gallica colonized and formed internal rhizomorphs within rhizomes established with TK-10 , suggesting that this mycobiont can replace and potentially can oust the latter. We infer that the orchid can associate with Armillaria and Desarmillaria mycobionts throughout its life, but that TK-10 enhances early growth. However, because TK-10 has a higher wood-rotting capacity than A. gallica , rapid resource exhaustion may cause nutrient supply shortages. We hypothesize that secondary colonization by Armillaria or Desarmillaria species triggers TK-10 displacement and that this mycobiont shift sustains orchid growth for longer., (2024, by The Mycological Society of Japan.)

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., (© 2022 The Authors. New Phytologist © 2022 New Phytologist Foundation.)

Hypomagnesemia is a characteristic adverse event of cetuximab in patients with head and neck cancer (HNC). However, there is limited information about its prevalence, risk factors, and preventive strategies. This study aimed to investigate the risk factors of hypomagnesemia and examine the preventive effects of prophylactic magnesium (Mg) administration. We initially investigated HNC patients treated with cetuximab between 2013 and 2019. Our institute started prophylactic Mg treatment (20-mEq Mg sulfate administration before cetuximab) in practice during this period. We retrospectively assess the preventive efficacy by comparing patients before and after its implementation. In total, 109 patients were included. In 60 patients without prophylaxis, all-grade and grade ≥2 hypomagnesemia at 3 months occurred in 61.7 and 15.0% of patients. The incidence of hypomagnesemia was not affected by regimens and concomitant medications. In 49 patients treated with prophylactic Mg treatment, there was no significant decrease in the cumulative incidence of hypomagnesemia. However, the preventive Mg treatment eliminated the need for additional Mg repletion to maintain Mg levels in patients treated with paclitaxel + cetuximab. A risk factor in patients without prophylaxis was a low Mg level at pre-treatment (≤2.0 mg/dL) (odds ratio: 6.03, 95% confidence interval: 1.78-20.4, p = 0.004), whereas that in patients with prophylaxis was the number of cetuximab doses (≥10) (odds ratio: 5.50, 95% confidence interval: 1.52-19.87, p = 0.009). In conclusion, a low pre-treatment Mg level was the only risk factor that could be avoided by prophylactic Mg administration. This preventive intervention is recommended for managing cetuximab-induced hypomagnesemia.

Orchids parasitically depend on external nutrients from mycorrhizal fungi for seed germination. Previous findings suggest that orchids utilize a genetic system of mutualistic arbuscular mycorrhizal (AM) symbiosis, in which the plant hormone gibberellin (GA) negatively affects fungal colonization and development, to establish parasitic symbiosis. Although GA generally promotes seed germination in photosynthetic plants, previous studies have reported low sensitivity of GA in seed germination of mycoheterotrophic orchids where mycorrhizal symbiosis occurs concurrently. To elucidate the connecting mechanisms of orchid seed germination and mycorrhizal symbiosis at the molecular level, we investigated the effect of GA on a hyacinth orchid (Bletilla striata) seed germination and mycorrhizal symbiosis using asymbiotic and symbiotic germination methods. Additionally, we compared the transcriptome profiles between asymbiotically and symbiotically germinated seeds. Exogenous GA negatively affected seed germination and fungal colonization, and endogenous bioactive GA was actively converted to the inactive form during seed germination. Transcriptome analysis showed that B. striata shared many of the induced genes between asymbiotically and symbiotically germinated seeds, including GA metabolism- and signaling-related genes and AM-specific marker homologs. Our study suggests that orchids have evolved in a manner that they do not use bioactive GA as a positive regulator of seed germination and instead autoactivate the mycorrhizal symbiosis pathway through GA inactivation to accept the fungal partner immediately during seed germination., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

To date, there has been no robust evidence for the exploitation of saprotrophic non-rhizoctonia fungi by green plants, although some fully mycoheterotrophic orchids are known to exploit them, and mycoheterotrophic evolution has probably occurred through intermediate mixotrophic stages. We investigated the physiological ecology of a fully mycoheterotrophic species Cremastra aphylla and its photosynthetic sister species Cremastra appendiculata, which putatively exploit saprotrophic fungi. Their mycorrhizal partners and ultimate nutritional sources were determined using molecular, stable isotopic, and radiocarbon analysis. Both Cremastra aphylla and Cremastra appendiculata were consistently associated with wood-decaying Psathyrellaceae. In addition, both species were highly enriched in carbon-13 ( 13 C) and, to a less degree, in nitrogen-15 ( 15 N). The δ 13 C and δ 15 N values of Cremastra appendiculata were intermediate between those of Cremastra aphylla and those of autotrophic plants. All Cremastra appendiculata samples and two Cremastra aphylla samples exhibited elevated Δ 14 C values due to the acquisition of carbon fixed in wood during the past decades ( 14 C-enriched bomb carbon). Our multifaceted evidence indicated that both species obtained carbon from deadwood via saprotrophic fungi. Our findings strongly suggest that mixotrophic relationships associated with wood-decaying fungi represent a novel evolutionary pathway for full mycoheterotrophy in orchids., (© 2021 The Authors. New Phytologist © 2021 New Phytologist Foundation.)

Exploring how organisms overcome geographical barriers to dispersal is a fundamental question in biology. Passive long-distance dispersal events, although infrequent and unpredictable, have a considerable impact on species range expansions. Despite limited active dispersal capabilities, many stick insect species have vast geographical ranges, indicating that passive long-distance dispersal is vital for their distribution. A potential mode of passive dispersal in stick insects is via the egg stage within avian digestive tracts, as suggested by experimental evidence. However, detecting such events under natural conditions is challenging due to their rarity. Therefore, to indirectly assess the potential of historical avian-mediated dispersal, we examined the population genetic structure of the flightless stick insect Ramulus mikado across Japan, based on a multifaceted molecular approach [cytochrome oxidase subunit I (COI) haplotypes, nuclear simple sequence repeat markers and genome-wide single nucleotide polymorphisms]. Subsequently, we identified unique phylogeographic patterns, including the discovery of identical COI genotypes spanning considerable distances, which substantiates the notion of passive long-distance genotypic dispersal. Overall, all the molecular data revealed the low and mostly non-significant genetic differentiation among populations, with identical or very similar genotypes across distant populations. We propose that long-distance dispersal facilitated by birds is the plausible explanation for the unique phylogeographic pattern observed in this flightless stick insect.