XTBG OpenIR

Species evolution determines epiphyte evolution in Orchids

2026-06-11T03:34:05Z

Title: Species evolution determines epiphyte evolution in Orchids Authors: Zhang, Tianwen; Zhai, Jun-Wen; Wang, Gang Description: Orchid diversity and conservation are tightly linked to the evolution of orchid lifeforms (e.g., epiphytic or terrestrial) as epiphytic species are highly sensitive to environmental changes and includes superhigh species diversity. However, the factors that drive the evolution of orchid lifeform remain unclear. Here, we used a global orchid phylogeny (2272 species, all five subfamilies and 302 genera) to evaluate the relative contributions of potential factors (i.e., phylogeny, climate region, pollination traits) that may drive orchid lifeform evolution using partial R2 framework. Conventional correlation results indicated that orchid lifeforms are strongly associated with climate regions and weakly related to pollination traits. In contrast, partial R2 analyses revealed that orchid phylogeny alone accounted for 62% of lifeform variation; pollinator attraction strategies independently explained an additional 23.9% variation, while climate region only further explained 3.4%. The discrepancies arise from variation in phylogenetic conservatism of different orchid traits: both orchid lifeform and climate region are more phylogenetically conserved than pollination traits. Specifically, our findings that species evolution plays a key role in lifeform evolution together with variation in phylogenetic conservatism among key traits provide insights into trait evolution and species conservation in orchids. (c) 2026 Kunming Institute of Botany, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The relative role of regional species pools in determining tree species richness and rarity in Chinese subtropical and tropical forests

2026-06-11T03:34:04Z

Title: The relative role of regional species pools in determining tree species richness and rarity in Chinese subtropical and tropical forests Authors: Song, Houjuan; Jimenez-Alfaro, Borja; Song, Yongchang; Svenning, Jens-Christian; Ordonez, Alejandro; Zhang, Oukai; Wang, Xihua; Yan, Enrong; Song, Kun; Lin, Luxiang; Chen, Shengbin; Yang, Qingpei; Li, Buhang; Wu, Chuping; Jiang, Bo; Jin, Chao; Zhang, Zhiming; Ding, Yi; Wan, Huilin; Shang, Kankan; Cao, Kunfang; Shi, Wei; Wang, Xin; Wang, Xiaoran; Liu, Pengcheng; Zhang, Jian Description: The species pool hypothesis argues that local species diversity mainly depends on regional diversity, which is influenced by dispersal, historical and current environmental conditions. We hypothesize that regional factors, such as the size of the regional species pool, current climate, topographical variability, and historical climate stability, also impact local species-abundance patterns, like the rarity of local species, though their specific effects are not yet well understood. Analyzing data from 3307 species across 3923 forest plots in Chinese subtropical and tropical regions, we employed boosted regression trees and structural equation modeling to assess the roles of regional species pool size along with climatic seasonality, topography, and soil factors, in shaping local richness and rarity. We found that local tree species richness declined with increasing latitude, while species rarity decreased from west to east. The factors such as current regional environment, paleoclimate stability, and human disturbance significantly affected local richness and rarity, primarily through their effects on regional species pool size. The impacts of regional mean temperature and elevational range on local richness surpassed local influences. Conversely, local climatic seasonality exerted the strongest influence on species rarity, followed by human activity. Overall, the findings indicate that regions with large regional species pools tend to support diverse communities with high proportions of rare species. (c) 2026 Kunming Institute of Botany, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Induction of glutathione and flavonoid biosynthesis activates antioxidant enzymes to enhance drought tolerance in rice

2026-06-11T03:34:03Z

Title: Induction of glutathione and flavonoid biosynthesis activates antioxidant enzymes to enhance drought tolerance in rice Authors: Chali, Biru Alemu; Li, Yunfang; Ahanger, Mohammad Abass; Thin, Phyu Phyu; Wan, Jinpeng; Xu, Peng Description: Drought stress during early seed germination severely impacts rice establishment and productivity, yet the molecular and metabolic mechanisms underlying drought tolerance at this stage remain poorly understood. In this study, Luying 46 (LY46), a drought-tolerant genotype, and Haogenai (HGN), a drought-sensitive genotype, were used to investigate key adaptive traits and regulatory networks that confer drought resilience during germination. LY46 showed higher germination rates, better shoot and root growth under drought stress compared to HGN. Integrated transcriptomic and metabolomic analyses revealed enhanced glycolysis, glutathione metabolism, and phenylpropanoid biosynthesis as central pathways supporting drought adaptation in LY46. Upregulation of genes involved in starch mobilization and sugar metabolism facilitated energy production under water deficit, while elevated antioxidant enzyme activities, flavonoids, phenolic acid and prolines, mitigated oxidative damage. Metabolite profiling further revealed accumulation of peptides, amines, nucleotides, alkaloids, lipids and fatty acids in LY46 under drought. Weighted gene coexpression network analysis (WGCNA) revealed the coordinated regulation of antioxidant, osmoprotectant, and metabolic pathways involved in alleviating drought stress. Biochemical assays confirmed LY46's maintenance of membrane integrity by effectively reducing lipid peroxidation under stress. Collectively, our comprehensive multiomics approach revealed a coordinated molecular and metabolic network regulated by transcription factors that underpins drought tolerance during rice germination, providing valuable insights into drought resilience in rice.

A global meta-analysis reveals coupled biogeochemical and microbial successional trajectories in forest soils

2026-06-11T03:39:01Z

Title: A global meta-analysis reveals coupled biogeochemical and microbial successional trajectories in forest soils Authors: Muhammad, Waseem; Yu, Xiaocheng; Wu, Jianping; Yang, Xiongxian; Mo, Yuxuan; Luo, Qiang; Feng, Leiyun; Pu, Xiaoyan; Zhou, Wenjun; Song, Liang; Lu, Huazheng; He, Xinhua Description:

Forest succession fundamentally reshapes soil biogeochemistry and the resident microbial communities, yet a synthesis of global response patterns has been hindered by methodological inconsistencies and conflicting regional findings. Through a meta-analysis of studies published from 2015 to 2025, we evaluated global patterns in soil properties, microbial communities across forest successional stages. We found that soil organic carbon (SOC) and total nitrogen (TN) increased significantly from early to late successional, while soil pH declined. Microbial alpha-diversity increased sharply from early to mid-succession before slightly declining in late stages. Structural equation modeling (SEM) indicated that TN is the primary positive driver of both bacterial and fungal diversity and community composition, whereas SOC, pH, and climate factors exhibited weaker or stage-specific effects. Community composition also shifts systematically from a predominance of fast-growing, copiotrophic taxa (e.g., Proteobacteria, Ascomycota) in early stages to slow-growing, oligotrophic specialists (e.g., Actinobacteriota, Basidiomycota) in late stages. Bacterial diversity was more sensitive to climatic variables (precipitation, temperature), while fungal communities were more strongly governed by soil nutrient availability. This synthesis reconciles disparate findings by demonstrating that forest succession drives predictable, coupled trajectories in soil nutrients and microbial community composition. Our results provide a mechanistic framework for understanding belowground ecosystem development and its functional implications for forest biogeochemistry.

Molecular basis of fatty acid composition diversity in different avocado cultivars

2026-06-11T03:34:00Z

Title: Molecular basis of fatty acid composition diversity in different avocado cultivars Authors: Chen, Minghui; Chen, Zhiyu; Lin, Fanfan; Cai, Yifan; Huang, Tianping; Zheng, Yan; Yin, Xin; Yang, Yongping; Kong, Xiangxiang; Yang, Yunqiang Description: Background Avocado (Persea americana Mill.), an evergreen tree belonging to the Persea genus in the Lauraceae family, is native to Central America and Mexico. Avocado fruit has become a global superfood and globally important economic crop because of its exceptionally high oil content and unique nutritional composition. Elucidating the differences in fatty acid composition among avocado cultivars and the underlying molecular regulatory mechanisms is highly important for the targeted breeding of high-quality cultivars of avocado. Results In this study, we systematically investigated the variation in and regulatory mechanisms of fatty acid composition in the fruits of five major avocado cultivars ('Hass', 'Zutano', 'Fuerte', 'Reed', and 'Pinkerton'). Through GC-MS analysis, significant differences in fatty acid profiles were detected among the cultivars. The 'Fuerte' cultivar presented the highest monounsaturated fatty acid content (70.71%), while the 'Hass' cultivar presented the greatest abundance of polyunsaturated fatty acids (22.21%). Transcriptome analysis revealed distinct expression profiles of genes involved in fatty acid metabolic pathways across different cultivars. Moreover, WGCNA identified the omega-6 fatty acid desaturase genes FAD2.1 and FAD2.2, which catalyze the conversion of oleic acid to linoleic acid, as key genes regulating linoleic acid biosynthesis. Further investigation revealed that the transcription factors PaARF16 and PaZIP18 modulate the transcriptional activity of FAD2.1 by binding to its promoter region, providing potential targets for molecular breeding improvements. Conclusion This study revealed the differences in fatty acid composition among different avocado cultivars and a potential molecular basis in fatty acid metabolism, providing new insights into the molecular mechanisms underlying avocado oil quality development and a genetic resource for improving oil quality.

Phylogenetic history shapes the composition of floral scents in a specialized pollination mutualism

2026-06-11T03:41:04Z

Title: Phylogenetic history shapes the composition of floral scents in a specialized pollination mutualism Authors: Cao, Li; Joffard, Nina; Segar, Simon T.; Souto-vilaros, Daniel; Johnson, Steven D.; Buatois, Bruno; Bagneres, Anne-genevieve; Hossaert-mcKey, Martine; Proffit, Magali Description:

Most studies of the chemical ecology of plant-pollinator interactions emphasize the role of pollinator-mediated selection in shaping floral scent composition. Nevertheless, phylogeny may constrain the metabolic pathways underlying these profiles, thereby influencing the evolutionary trajectory of the emitted signals. To investigate whether phylogenetic history constrains plant chemical communication, we used the obligate fig-fig wasp mutualism. We collected floral scents from receptive figs of 32 Ficus species, representing diverse lineages across tropical and subtropical regions, using dynamic headspace extraction. Chemical compositions were analyzed via gas chromatography-mass spectrometry and evaluated for the phylogenetic signal using multivariate analyses. Our results revealed a strong phylogenetic signal in the volatile organic compounds (VOCs) emitted by receptive figs. Conversely, using the same analysis, we found no relationship between the scent profile and the pollinator phylogeny. Our findings demonstrate, across diverse Ficus lineages, that phylogenetic constraints play a significant role in the diversification of VOC signals emitted by receptive flowers, suggesting constraints in the biosynthetic pathways of volatile compounds.

Impact of processing techniques on chemical compositions and sensory attributes across five types of Yunnan large-leaf teas

2026-06-11T03:42:27Z

Title: Impact of processing techniques on chemical compositions and sensory attributes across five types of Yunnan large-leaf teas Authors: Dang, Xueqing; Li, Yunfang; Lv, Zixian; Lu, Fengmei; Li, Wen; Zhang, Yi; Shi, Xiaoyu; Yi, Guimei; Duan, Hongxing; Hou, Yan Description:

Distinct processing techniques form five types of Yunnan large-leaf teas. Besides sensory evaluation, HPLC, UHPLC-QTrap-MS/MS and HS-SPME-GC-MS were performed to explore the overall impact of processing techniques through comparisons among these five types of teas. Principal component analysis basically divided these teas into three groups, confirming that pile-fermentation and anaerobic fermentation have more profound impacts on organic acids, flavonoids and non-volatile metabolites than other typical processes. Different from phenolics oxidative polymerization in enzymatic oxidation and pile-fermentation to formulate thearubigins and theabrownins, anaerobic fermentation of pickled tea (PT) transformed ester catechins and rutin into four nonester catechins and three simple flavonols (i.e. quercetin, kaempferol and myricetin), respectively. Despite similar volatile profile to raw Pu-erh tea, characteristic organic acids such as succinic acid, lactic acid and 3-phenyllactic acid were formed in anaerobic fermentation, and contributed to sour flavor of PT. This study would promote standardization and optimization for Yunnan tea production.

Available nutrients and microbial alpha diversity contribute to CO2 emission in a subtropical primary forest: insight from a 4 m soil vertical profile

2026-06-11T03:43:08Z

Title: Available nutrients and microbial alpha diversity contribute to CO2 emission in a subtropical primary forest: insight from a 4 m soil vertical profile Authors: Chen, Deyun; Lu, Zhiyun; Wang, Yanping; Hou, Chunyu; Wu, Jianping Description:

CO2 released into the atmosphere through soil respiration represents the second-largest carbon flux between terrestrial ecosystems and the atmosphere. While extensive research has concentrated on surface soils, limited studies have explored CO2 emission patterns and their primary drivers across varying soil depths. In this study, soil CO2 emissions were measured using static chambers at six different depths (10, 50, 100, 200, 300 and 400 cm) in a primary forest. Additionally, potential influencing factors, including soil physical and chemical properties, microbial diversity and community structure and function, were assessed. The results demonstrated that soil nutrients, along with fungal and bacterial diversity, generally declined with increasing soil depth. Soil CO2 emissions also decreased significantly with depth, driven primarily by biotic factors such as fungal and bacterial alpha diversity and abiotic factors such as ammonium nitrogen and available phosphorus. These findings provide new insights into the mechanisms of carbon cycling within deep soil layers in forest ecosystems.

Joint Influence of Seed Dormancy and Dispersal Syndrome on Dispersal Distance and Range Size Across Two Climate Regions

2026-06-11T03:44:28Z

Title: Joint Influence of Seed Dormancy and Dispersal Syndrome on Dispersal Distance and Range Size Across Two Climate Regions Authors: Cai, Wang; Liu, Yuan; Li, YunAo; Cao, Min; Baskin, Carol C.; Baskin, Jerry M.; Alzate, Adriana; Onstein, Renske E.; Yang, Jie Description:

Aim Long distance dispersal and the ability to delay germination under unfavourable conditions (dormancy) are critical for plant persistence and range expansion. However, how dispersal syndrome and dormancy interactively shape maximum dispersal distance and species range size across climate regions remains unclear. We tested the hypothesis that a trade-off between dormancy and dispersal distance operates differently in animal-mediated versus abiotic dispersal systems, and that climate modulates their influence on range size.Location Global.Time Period Current.Major Taxa Studied Seed plants.Methods We compiled data on dormancy, dispersal syndrome, maximum seed dispersal distance and range size for 631 plant species across 118 families worldwide. We used linear mixed effects models to examine how dormancy and dispersal syndromes interactively shape seed dispersal distance and range size across tropical and temperate regions.Results Non-dormant species had larger maximum dispersal distances than dormant species, but only in abiotic dispersal systems, consistent with a trade-off between dispersal and persistence traits (dormancy). In contrast, animal-mediated dispersal led to larger dispersal distances than abiotic dispersal, regardless of whether species were dormant or not. The influence of dormancy and dispersal syndrome on range size was climate-dependent. In tropical regions, animal-mediated dispersal enhanced range size, while dormancy had little effect. In temperate regions, maximum seed dispersal distance was positively associated with range size, but neither dormancy nor animal-mediated dispersal significantly affected range size.Main Conclusions The interplay between seed dormancy and dispersal syndromes shapes seed dispersal distance and species range size in climate-specific ways. Animal-mediated dispersal promotes larger maximum dispersal distances and larger range sizes in tropical regions. In contrast, in abiotic dispersal systems, dormancy leads to relatively small dispersal distances, but dormancy itself does not affect range sizes in temperate or tropical regions. Understanding dispersal-dormancy dynamics is essential for predicting how plants will respond to environmental changes.

Differential responses of termite gut bacterial and fungal community to tropical forest conversion

2026-06-11T03:45:00Z

Title: Differential responses of termite gut bacterial and fungal community to tropical forest conversion Authors: Jia, Zhizhou; Meng, Yuanyuan; Wang, Wenting; Behm, Jocelyn; Cai, Feng M.; Mishra, Sandhya; Xia, Shangwen; Liu, Shengjie; Yang, Xiaodong Description:

Land-use change significantly impacts biodiversity, but its effects on the gut microbiomes of soil invertebrates remain poorly understood. We investigated how forest conversion to rubber plantations alters bacterial and fungal diversity, composition, and function in termite guts within a biodiversity hotspot Xishuangbanna, China. Our results showed that termites from natural forests harbored higher gut bacterial diversity than those from plantations, with effects varying across host species. Fungal diversity was shaped primarily by host species identity, with Odontotermes yunnanensis exhibiting the highest diversity index. While termite species solely governed bacterial community composition, both termite species and forest type shaped fungal composition. Fungal community variation correlated with local soil properties, whereas bacterial variation only associated with soil pH. Termites shared 17% of core gut bacteria (e.g., Bacillus, Pseudomonas, Mycobacterium) but 100% of fungi with the environment. Co-occurrence networks exhibited species-specific responses to forest conversion. Host species (Ancistrotermes and Odontotermes) predicted bacterial functional potential, but both forest type and host species influenced fungal functional potential. These findings demonstrate that termite gut microbiome responses to land-use change are multifaceted and taxon-specific, highlighting their role in ecosystem functional resilience under anthropogenic disturbance.