Frontiers in Plant Science最新文献

{"title":"Light-dark dependent changes in chloroplast and mitochondrial activity in <i>Chlamydomonas reinhardtii</i>.","authors":"Gunjan Dhawan, Basuthkar Jagadeeshwar Rao","doi":"10.3389/fpls.2025.1622214","DOIUrl":"https://doi.org/10.3389/fpls.2025.1622214","url":null,"abstract":"<p><p>In photosynthetic organisms, the inter-organellar coordination between photosynthetic and respiratory processes is fundamental for maintaining cellular energy homeostasis. These organelles not only operate distinct bioenergetic pathways but also engage in extensive metabolic cross-talk to balance energy production, redox status and metabolic demands, especially under fluctuating light-dark conditions. Such coordination has been widely appreciated across plant and algal systems but it remains relatively less explored, particularly in synchronous cultures where cellular rhythms can be more precisely examined. Our study investigated the coordination in photosynthetic and mitochondrial activity during (12:12 h) light-dark cycle using synchronized <i>Chlamydomonas reinhardtii</i> cultures. Live cell confocal imaging revealed light-dark-dependent mitochondrial morphology transitions from fragmented to intermediate to tubular forms by the end of 12 hr of light period, which reverses sharply through 6 and 12 hr of dark. Concurrently, chloroplast show novel transitions from an intact cup (light) to a distorted and punctured structure (dark), which gets reversed in light phase. Spatial mapping showed tubular mitochondria positioned peripherally to the chloroplast cup in light, whereas fragmented and intermediate mitochondria were diffused around distorted chloroplast in dark, which again gets reversed in light. Functional analysis using 77K spectroscopy and photosynthetic protein levels (PsaA and D1) reflected that PSI/PSII fluorescence ratio remains stable in continuous light condition but increased exceptionally in continuous dark, which led to transient changes observed in fluorescence ratio in light/dark-dependent manner in synchronous cultures. Mitochondrial activity, measured using Seahorse flux analyzer, showed basal oxygen consumption rate in continuous light and a marked reduction in continuous dark condition, resulting in dynamic changes observed in light-dark cycle, indicating a coordination in the organellar function. Further, Target of rapamycin (TOR) kinase activity was essential to maintain inter-organellar coupling as evidenced by subdued fluctuations following TOR kinase inhibition. The study, for the first time, argues for (12:12 h) light-dark cycle-mediated coupled dynamics between mitochondria and chloroplast in <i>C. reinhardtii</i>, offering new insights into the temporal regulation of cellular energy dynamics.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1622214"},"PeriodicalIF":4.1,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310610/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144759832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>In planta</i> transformation methods to accelerate the domestication of perennial grain crops.","authors":"Pedro M P Correia, Xinyi Dong, Mengming Chen, Anton Frisgaard Nørrevang, Guangbin Luo, Michael Palmgren","doi":"10.3389/fpls.2025.1638144","DOIUrl":"https://doi.org/10.3389/fpls.2025.1638144","url":null,"abstract":"<p><p>The domestication of grasses has historically favored annual species due to their rapid growth and suitability for crop rotation; however, such crops rely heavily on human input. In contrast, perennial grasses, which live for multiple years, offer significant environmental benefits, such as improved soil health and natural resilience to biotic and abiotic stress, but have not yet been domesticated. Gene editing of yield-related genes presents an opportunity to improve yield stability in perennial cereal crops. However, this process typically requires transformation to introduce gene-editing tools, and many perennial grasses are recalcitrant to traditional <i>in vitro</i> transformation. Alternative <i>in planta</i> transformation methods have recently emerged, offering simpler, faster, and more genotype-independent approaches. These methods bypass the need for tissue culture and could potentially be used to transform recalcitrant plants more efficiently. In this review, we evaluate the potential of <i>in planta</i> transformation methods for developing perennial cereal crops and advocate for exploring the role of such crops in sustainable agriculture.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1638144"},"PeriodicalIF":4.1,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310747/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144759814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of the impact of ecological factors on the habitat suitability and bioactive components accumulation of the medicinal holoparasitic plant <i>Cynomorium songaricum</i> using machine learning models.","authors":"Jiacheng Ji, Xinxin Wei, Huan Guan, Zikang Jin, Xin Yue, Zhuoran Jiang, Youla Su, Shuying Sun, Guilin Chen","doi":"10.3389/fpls.2025.1586682","DOIUrl":"https://doi.org/10.3389/fpls.2025.1586682","url":null,"abstract":"<p><p>The efficacy of traditional Chinese medicine is determined by its bioactive components, which exhibit variability depending on environmental conditions and hereditary influences. In this study, we focus on <i>Cynomorium songaricum</i> Rupr., a medicinally significant species facing sustainability challenges. However, the ecological drivers governing its distribution, as well as the relationship between environmental factors and bioactive components, remain unclear. Thus, we sampled 28 representative distribution areas of <i>C. songaricum</i> in China. Employing Maximum Entropy (MaxEnt) modeling, we projected current and future (2050s-2090s) habitat suitability under four emission scenarios. Notably, species distribution exhibited expansion (8.03%-29.06% range increase across scenarios) with precipitation of the wettest month (BIO13) and soil pH emerging as key drivers (combined contribution >49%). Ultra-performance liquid chromatography (UPLC) fingerprinting combined with machine learning regression was applied to quantify six key bioactive components in <i>C. songaricum</i>, 3,4-dihydroxybenzaldehyde, catechin, epicatechin, ursolic acid, total phenolics, and crude polysaccharides-revealing significant concentration variations among geographically distinct populations. Slope gradient (slope), min temperature of coldest month (BIO6), precipitation of coldest quarter (BIO19), sunshine duration in growing season(hsdgs), and isothermality (BIO3) were identified as key regulatory factors influencing the accumulation of multiple components. Specifically, slope acted as a key shared negative regulator for 3,4-dihydroxybenzaldehyde, catechin, and crude polysaccharides. BIO6 served as a key shared positive regulator for catechin and total phenolics, while functioning as a key negative regulator for ursolic acid. BIO19 was identified as a key shared negative regulator for catechin and epicatechin. Hsdgs acted as a key positive regulator for ursolic acid while negatively regulating crude polysaccharides. Additionally, BIO3 served as a key shared positive regulator for both ursolic acid and total phenolics. This study provides the scientific basis for enabling targeted cultivation zones that balance therapeutic compound yield with arid ecosystem conservation.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1586682"},"PeriodicalIF":4.1,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310582/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144759829","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating climate-smart practices in forestry: insights from Europe and America.","authors":"Hongtao Xie, Mengyuan Chang, G Geoff Wang, Yu Tang, Songheng Jin","doi":"10.3389/fpls.2025.1583294","DOIUrl":"https://doi.org/10.3389/fpls.2025.1583294","url":null,"abstract":"<p><p>Global climate change poses a great obstacle to the sustainability of world forestry, and the trifecta of enhancing forest stock, minimizing greenhouse gas emissions, and attaining sustainable forest management is still challenging. Climate-smart forestry (CSF), however, offers promising solutions to these issues, with its core objective being to foster sustainable development through enhanced forest resilience, reduced greenhouse gas emissions, and boosted forest productivity and income. This emerging focus on CSF seeks to understand the mechanisms of interactions between forest ecosystems and climate change and eventually find locally acceptable solutions. This review delves into the developmental objectives of CSF, providing a new insight into the latest research advances and practical experience in CSF among eight Europe and American countries, including Brazil, USA, Czech, Finland, etc. Meanwhile, we identify the main challenges that CSF is facing currently, including the climate change uncertainty, disconnection among policy, science, and practice, and trade-offs between different CSF objectives. To address these challenges, we proposed five potential aspects for CSF development and sketched their main applications. Specifically, Technological innovation and digital applications are highly encouraged, including GIS and remote sensing, Internet of Things (IoT), and artificial intelligence technologies. Besides, Intelligent logging operations and wood processing, forest bioeconomy should also be considered to promote the CSF development. The results offer new perspectives and strategies for mitigating climate change via sustainable forestry management and protecting forest economies and communities in the context of accelerated global climate change.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1583294"},"PeriodicalIF":4.1,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310691/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144759831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nitrogen content estimation of apple trees based on simulated satellite remote sensing data.","authors":"Meixuan Li, Xicun Zhu, Xinyang Yu, Cheng Li, Dongyun Xu, Ling Wang, Dong Lv, Yuyang Ma","doi":"10.3389/fpls.2025.1613487","DOIUrl":"https://doi.org/10.3389/fpls.2025.1613487","url":null,"abstract":"<p><strong>Introduction: </strong>Using satellite remote sensing technology to diagnose apple tree nitrogen content is critical for guiding regional precision fertilization of apple trees. However, due to differences in spatial resolution and spectral response, there is a lack of systematic evaluation of satellite data's applicability and accuracy in apple tree nitrogen inversion.</p><p><strong>Methods: </strong>This study used apple orchards in Qixia City, Shandong Province as the research area, collecting canopy hyperspectral data through an ASD spectrometer during three key phenological periods: the new-shoot-growing stage (NGS), the new-shoot-stop-growing stage (NSS), and the autumn shoot-growing stage (ASS). The data was resampled based on satellite sensor spectral response functions to match the band resolutions of multiple satellite sources. Correlation coefficient method and partial least squares regression were used to screen sensitive bands for apple tree nitrogen content. Support Vector Machine (SVM) and Backpropagation Neural Network (BPNN) algorithms were used to construct and screen the optimal models for apple tree nitrogen content estimation.</p><p><strong>Results: </strong>Results showed that visible light, red edge, near-infrared, and yellow edge bands were sensitive bands for estimating apple tree nitrogen content. The support vector machine model constructed based on Sentinel-2 satellite simulated data was the optimal nitrogen content inversion model, with an average R^² value of 0.81 and an average RMSE value of 0.15 for training sets across different phenological periods, and an average R² value of 0.61 and an average RMSE value of 0.23 for validation sets.</p><p><strong>Discussion: </strong>This study systematically evaluated the applicability and accuracy differences of multi-source satellite data for estimating nitrogen content in apple trees, and clarified the variation patterns of nitrogen-sensitive spectral bands and optimal modeling strategies across key phenological stages. This research provides a scientific basis for data selection and a technical paradigm for remote sensing-based nutrient diagnosis of apple trees at the regional scale, and holds significant theoretical and practical value for developing region-wide precision fertilization systems based on remote sensing.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1613487"},"PeriodicalIF":4.1,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12310676/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144759833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating lowland coffee genotypes against leaf rust and wilt diseases in southwestern Ethiopia.","authors":"Hailu Negesa, Gabisa Gidisa, Zenebe Wubshet, Desalegn Alemayehu, Kifle Belachew, Wakuma Merga, Lemi Beksisa, Dawit Merga, Mohammedsani Zakir","doi":"10.3389/fpls.2025.1560091","DOIUrl":"10.3389/fpls.2025.1560091","url":null,"abstract":"<p><strong>Introduction: </strong>Coffee is one of the most economically essential agricultural commodities worldwide and in Ethiopia in particular. Despite its importance, it is constrained by different factors. Among these, coffee leaf rust, caused by <i>Hemileia vastatrix</i>, and wilt diseases, caused by <i>Gibberella xylarioides</i>, are major limiting factors of coffee production. However, Ethiopia has not yet reported a commercialized resistant variety for both of these diseases. Therefore, the present study was conducted to evaluate lowland coffee genotypes against coffee leaf rust and wilt diseases under field and greenhouse conditions, respectively.</p><p><strong>Methods: </strong>A field experiment was conducted across four locations (Agaro, Teppi, Bebeka, and Gelesha) from 2021 to 2023. A randomized complete block design with three replications was used. The experiment for wilt disease was conducted on seedlings using seedling stem-nicking inoculation techniques.</p><p><strong>Results: </strong>The results revealed a significant difference among the genotypes in reaction to leaf rust and wilt diseases. Among the tested genotypes, I-1, I-2, K-1, and K-2 consistently showed a highly resistant reaction to leaf rust across locations, whereas one genotype (EB-1) indicated a susceptible reaction across all locations. The highest mean leaf rust severity was recorded on EB-1 (27.1%), while the lowest severity was recorded on genotype I-2 (0.35%). Similarly, four genotypes (I-1, I-2, K-1, and K-2) showed moderate resistance to wilt disease and indicated an extended incubation period compared to the susceptible control (Geisha).</p><p><strong>Discussion: </strong>Analysis of genotype by environment (G×E) interaction indicated a highly significant interaction (P < 0.01). Among climate factors, relative humidity and maximum temperature showed a highly significant and positive correlation with coffee leaf rust. These resistant genotypes could be used by farmers as a component of integrated disease management in coffee leaf rust-prone areas of the country. In addition, end users must integrate these genotypes with other wilt management options. Overall, these genotypes can enhance the resilience of coffee production when combined with other management strategies for coffee leaf rust and wilt diseases across the lowland coffee production areas of Ethiopia.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1560091"},"PeriodicalIF":4.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12307361/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144753065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of gene expansion and defense-related genes in Anacardiaceae family from an evolutionary aspect.","authors":"Bing-Liang Fan, Lin-Hua Chen, Ling-Ling Chen","doi":"10.3389/fpls.2025.1638044","DOIUrl":"10.3389/fpls.2025.1638044","url":null,"abstract":"<p><strong>Introduction: </strong>The Anacardiaceae family, encompassing economically and ecologically significant genera such as <i>Rhus</i>, <i>Mangifera</i>, and <i>Pistacia</i>, exhibits substantial genomic diversity and adaptive complexity. However, comparative genomic analysis and evolutionary insights into defense-related mechanisms within this family remain underexplored.</p><p><strong>Methods and results: </strong>This study employed a comprehensive phylogenomic, synteny, and gene family analysis across six <i>Rhus</i> species and three additional Anacardiaceae plants (<i>Mangifera indica</i>, <i>Pistacia vera</i>, and <i>Anacardium occidentale</i>). Our findings revealed distinct evolutionary trajectories: <i>Mangifera</i>/<i>Anacardium</i> underwent lineage-specific whole-genome duplications (WGDs) with chromosomal rearrangements, while <i>Rhus</i>/<i>Pistacia</i> retained only the ancestral gamma duplication. <i>Pistacia</i>'s genome expanded via transposable elements (TEs), whereas <i>Rhus</i> conserved chromosomal synteny despite accumulating TE-mediated structural variations. Some defense-related gene families, including WRKY transcription factors and nucleotide-binding leucine-rich repeat (NLR) genes, displayed substantial expansions and stress-responsive expression patterns, with 31 WRKY genes significantly upregulated during aphid infestation. NLRs clustered on chromosomes 4/12 showed positive selection signatures. Long terminal repeat retrotransposons exhibited Pleistocene-era activation bursts, potentially linked to climatic adaptation.</p><p><strong>Discussion: </strong>This study unveils TE-mediated diversification as a key driver of Anacardiaceae evolution, complementing WGD-dependent strategies in tropical lineages. The identification of lineage-specific structural variations, dynamic TE activities, and clustered defense-related genes highlights adaptive trade-offs shaped by biotic stresses and the biogeographic history of Anacardiaceae species. This study lays the groundwork for leveraging these genomic resources to enhance stress resilience and adaptive potential in economically important Anacardiaceae crops.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1638044"},"PeriodicalIF":4.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12307512/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144753062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic variation and genome-wide association analysis of nitrogen use efficiency-related traits under combined heat and nitrogen-deficient stress in an <i>Aegilops tauschii</i>-derived wheat population.","authors":"Amir Ibrahim Ismail Emam, Izzat Sidahmed Ali Tahir, Nasrein Mohamed Kamal, Yasir Serag Alnor Gorafi, Hisashi Tsujimoto, Takayoshi Ishii","doi":"10.3389/fpls.2025.1621916","DOIUrl":"10.3389/fpls.2025.1621916","url":null,"abstract":"<p><p>Heat stress and nitrogen (N) deficiency increasingly limit global wheat (<i>Triticum aestivum</i> L.) yields, highlighting the need to improve nitrogen use efficiency (NUE) under combined stresses for sustainable production. We assessed 145 multiple-synthetic-derivative (MSD) lines, carrying alleles from diverse <i>Ae. tauschii</i>, crossed and backcrossed into 'Norin 61', together with three checks across six field environments combining heat stress and either optimal (86 kg N ha^-¹; HS-HN) or zero (HS-LN) N supply in central Sudan. Eighteen agronomic and physiological traits were recorded, and best linear unbiased estimates were used for genome-wide association analysis (GWAS) with 31,362 high-quality DArTseq and GRAS-Di markers. HS-LN reduced mean grain yield (GY) and grain N uptake (GNUp) by 14% and 28%, respectively, but increased thousand-kernel weight and harvest index, indicating resource re-allocation to grain filling. The MSD lines showed wide variation, and some lines maintained high GY under either HS-HN (e.g., MSD053 and MSD450) or HS-LN (e.g., MSD192 and MSD383). The MSD lines MSD026, MSD181, and MSD485 ranked among the top five for GY under HS-LN, HS-HN conditions, and across the six environments. GWAS identified 34 marker-trait associations (MTAs) on 12 chromosomes; 62% resided in the D subgenome. A pleiotropic locus on 5A (rs987242) affected grain growth rate and GY, whereas a novel locus on 3D (rs1071033) explained 88% of the variation in GNUp relative performance. Candidate genes included mitogen-activated protein kinases, DELLA (Rht-1), MADS-box, and DnaJ homologues linked to stress signaling or N metabolism. Our results uncover genetic variants and germplasm that enhance NUE and yield stability under concurrent heat and N stress, providing immediately deployable resources for climate-resilient wheat breeding.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1621916"},"PeriodicalIF":4.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12307305/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144753173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identification and evaluation of phenotypic characters and genetic diversity analysis of 1,558 foxtail millet germplasm resources for conservation and breeding.","authors":"Xinwei Xue, Zhikun Yu, Ankang Mu, Fan Yang, Dan Liu, Shi Zhang, Jialin Zhang, Yao Cheng, Yushan Zhao, Yongping Zhang, Xianrui Wang","doi":"10.3389/fpls.2025.1624252","DOIUrl":"10.3389/fpls.2025.1624252","url":null,"abstract":"<p><p>Foxtail millet (<i>Setaria italica</i>) is a specialty mixed grain crop that originated in China. This study comprehensively assessed the phenotypic variability of 1,558 foxtail millet accessions to explore their genetic diversity and facilitate effective germplasm conservation. A total of 25 traits, including 11 quantitative and 14 qualitative, were investigated based on the quantization of physical and chemical descriptors and digital image analysis. The findings revealed significant variations in the coefficient of variation (CV) among the quantitative traits, which ranged from 3.90-28.38%. That of the qualitative traits ranged from 7.44-66.20%. The Shannon-Wiener Index (H') of the quantitative traits ranged between 1.86-2.08, and that of the qualitative traits ranged from 0.04-1.40. High genetic diversity was also detected among the 1,558 accessions. Based on hierarchical clustering, 1,558 accessions were separated into five categories. The principal component analysis (PCA) results indicated that 10 principal components were extracted when the cumulative contribution rate of the phenotypic traits reached 64.30%. The comprehensive evaluation F-values calculated based on correlation and PCA analyses of 25 phenotypic traits were applied to all the accessions, and the top 10 varieties were identified. Collectively, this study showed the rich genetic diversity of the 1,558 foxtail millet accessions, which could provide a baseline for breeding new millet varieties.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1624252"},"PeriodicalIF":4.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12307377/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144753174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal drought shapes the relationship between stem CO₂ efflux and belowground respiration in an even-age rubber plantation on Hainan Island, China.","authors":"Xinwei Guo, Bo Song, Rui Sun, Guoyu Lan, Bangqian Chen, Chuan Yang, Zhixiang Wu","doi":"10.3389/fpls.2025.1552859","DOIUrl":"10.3389/fpls.2025.1552859","url":null,"abstract":"<p><strong>Introduction: </strong>Stem CO₂ efflux (<i>E_c</i> ) reflects the amount of photo-assimilated carbon released back into the atmosphere and plays a critical role in the carbon balance of tree and forest ecosystems. Despite previous studies indicating that a portion of stem CO₂ originates from root respiration (<i>R_root</i> ), the seasonal dynamics of <i>E_c</i> and its relationship with belowground respiration remain poorly understood, particularly in tropical regions characterized by distinct dry and wet seasons.</p><p><strong>Methods: </strong>To address this gap, we investigated <i>E_c</i> in tapping and non-tapped rubber trees, along with environmental factors and physiological traits (sap flow flux density, root respiration, and leaf area index) from 2018 to 2021.</p><p><strong>Results: </strong>Our results showed that tapping activity increased the <i>E_c</i> of rubber trees compared to non-tapped trees, with increases ranging from 10.37% to 233.66%. However, the magnitude of this increase varied between the dry and wet seasons. Although tapping enhanced the <i>E_c</i> , it did not alter the <i>E_c</i> seasonal pattern. Consequently, <i>E_c</i> in both tapped and non-tapped rubber trees displayed an overall single-peak pattern, with significantly lower values during the dry season compared to the wet season, suggesting growth phenology primarily regulates <i>E_c</i> seasonal dynamics. Structural equation modeling revealed that root respiration (<i>R_root</i> ), sap flow flux density (<i>F_d</i> ), and soil moisture at 50 cm depth as the primary drivers of the <i>E_c</i> variations during the dry season. In contrast, soil moisture at 5 cm depth and air temperature (<i>T_a</i> ) were identified as dominant factors influencing <i>E_c</i> in the wet season, with belowground respiration having a negligible influence.</p><p><strong>Discussion: </strong>These results suggest that the relationship between <i>E_c</i> and belowground respiration is environmentally sensitive and exhibits seasonal dependency.</p>","PeriodicalId":12632,"journal":{"name":"Frontiers in Plant Science","volume":"16 ","pages":"1552859"},"PeriodicalIF":4.1,"publicationDate":"2025-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12307319/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144753178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}