Frontiers in Plant Science最新文献

Resistant starch (RS) plays an important physiological role in maintaining human health. However, increasing RS content in rice often comes at the cost of deteriorating its eating and cooking qualities (ECQs). In order to address this conflict, we conducted co-localization quantitative trait locus (QTL) analysis for RS in raw rice flour (RSm), cooked rice (RSc), retrograded rice (RSr) along with correlation analysis between RS and ECQs, using recombinant inbred line (RIL) populations derived from a cross of CG133R and Javanica 22. A total of 33 QTLs associated with RSm, RSc, RSr, RSa, and RSb were identified. These included two major QTLs on choromosome 6 (Wx and SSIIa), and several novel minor-effect QTLs such as q2ERSc3.2, q2ERSb5.1, and q2ERSb9.1 on choromosome 3, 5 and 9, respectively. Wx accounted for 27.34%, 64.16%, 68.07%, 29.95%, and 39.62% of the phenotypic variance for RSm, RSc, RSr, RSa (RSm-RSc), and RSb (RSr-RSc), respectively. Meanwhile, SSIIa explained 42.42%, 17.82%, 14.09%, and 51.16% of the phenotypic variance for RSm, RSc, RSr, and RSa. Furthermore, the thermal and retrogradation properties demonstrated positive correlations with RSm, but negative correlations with RSc and RSr, which was attributed to the differential regulation of Wx and SSIIa. Wx^a-SSIIa^G-GC regulated high RSm and RSa, while Wx^a-SSIIa^G-TT significantly increased RSc and RSr. Notably, Wx^a-SSIIa^G-TT haplotype improved the rice ECQs by reducing gelatinization temperature, preventing retrogradation and enhancing viscosity properties. Thus, this study identified an excellent haplotype, Wx^a-SSIIa^G-TT , which enhanced RSc and RSr and improved rice ECQs, providing useful information for breeding high-RSc rice with a relative superior quality.

To address seed decay in direct-seeded rice caused by waterlogging resulting from inadequate field leveling, this study conducted split-split-plot field experiments in Chongzhou City, Sichuan Province (103°38'31''-103°39'22'' E, 30°33'16''-30°33'54'' N). Specifically, two hybrid rice varieties previously identified as flood-resistant (V1: Jinyou 1319) and flood-sensitive (V2: Jingliangyou 1377) were assigned to the main plots, wet direct seeding (P1) and water direct seeding (P2) were compared in the subplots, and the coating (C1) and no-coating (C2) treatments were applied to the sub-subplots. In the coating treatment with water direct seeding, the seedling percentage of V1 and V2 increased by 25.58% and 78.54%, respectively, the number of effective panicles increased by 4.69% and 12.95%, respectively, and the seed setting rate improved by 15.05% and 16.64%, respectively. This synergy boosted the yields of the two varieties by 23.15% and 31.77%. In particular, the yield of V2 with water direct seeding with coating matched that under wet direct seeding without coating. With little difference in total energy consumption (≤ 1.88%), the sensitive variety with water direct seeding and coating saved irrigation water and labor inputs by 13% and 17%, respectively, in the demonstration area (calculated based on the input of the demonstration area). With water direct seeding, the stable oxygen supply from the coating improved the seed germination rate and seedling growth vitality, especially for the sensitive variety. Thus, the oxygen-releasing coating achieved yield increases, resource conservation, and efficiency enhancement synergistically, providing a valuable solution for the development of direct-seeded rice in China's hilly regions.

Introduction: Extreme winter cold in the Lancang River dry-hot valley limits vegetation establishment. Selecting cold-tolerant native species is therefore critical for ecological restoration and for maintaining stable agro-vegetation. This study aimed to assess cold tolerance in representative native shrubs and herbs using an integrated physiological and biochemical approach.

Methods: Seedlings of three shrubs (Sophora davidii, Vitex negundo var. microphylla, Rumex hastatus) and two herbs (Arthraxon lanceolatus, Artemisia vestita) were exposed to temperatures from 25°C down to -35°C in growth chambers. We quantified membrane injury (relative electrolyte leakage and semilethal temperature, LT50), gas exchange, chlorophyll fluorescence, osmolyte levels (proline, soluble sugars), and antioxidant enzyme activities (e.g., superoxide dismutase). Multivariate analyses (principal component analysis and membership functions) were used to develop an integrated cold-tolerance index.

Results: Semilethal temperature (LT50) differed markedly among species (approximately -27°C in S. davidii vs -5°C in A. lanceolatus), indicating a wide range of freezing tolerance. Across the freezing gradient, S. davidii maintained the lowest electrolyte leakage and partial Photosystem II efficiency, while accumulating high proline and soluble sugar levels and sharply increasing superoxide dismutase activity. In contrast, A. lanceolatus showed rapid membrane leakage and fluorescence declines. The most informative cold-response traits were Photosystem II efficiency and electrolyte leakage. An integrated cold-tolerance index based on multiple physiological metrics ranked species from highest to lowest tolerance as A. vestita > A. lanceolatus > V. negundo > R. hastatus > S. davidii. This ranking differed notably from the ranking based on LT50 alone.

Discussion: The discrepancy between the multi-trait index and single-trait (LT50) ranking highlights the risk of inferring cold tolerance from one metric. Acute stress responses (membrane stability, photosynthesis) and long-term freezing thresholds capture complementary aspects of cold tolerance. The derived physiological thresholds and the multi-indicator framework provide practical guidance for selecting and breeding native species for ecological restoration and cold-resilient agriculture in dry-hot valleys.

Central America is an understudied global hotspot of plant biodiversity and harbors Acrocomia aculeata (Coyol or Macaúba), a neotropical palm with significant potential for oil and biofuel production. Historically, the region has functioned as a biogeographic land bridge, an isthmus, connecting North and South American biota. Here, we investigate how genomic diversity and potential distribution patterns of A. aculeata are shaped across Central America. A total of 259 samples were collected from Guatemala, Honduras, Nicaragua, Costa Rica, and Panama, covering the full extent of the Central American isthmus. Using a double-digest genotyping-by-sequencing (ddGBS) approach and ecological niche modeling, we assessed variation at 1,523 single nucleotide polymorphisms (SNPs) and evaluated environmental suitability across the region. Our analyses reveal three major genomic clusters: Mesoamerican, Costa Rican, and Panamanian, each comprising subpopulations with distinct levels of genetic diversity. The Mesoamerican group (Guatemala, Honduras, and northern Nicaragua) exhibited the highest diversity and unique genetic signatures, likely reflecting historical migrations and acting as a biodiversity cradle during periods when southern portions of the isthmus were submerged. Biogeographic features such as the Nicaraguan Depression and the Talamanca Cordillera contributed to regional genetic differentiation. Ecological niche models identified Central American pacific lowlands, forested areas, rangelands, and agroecosystems as suitable habitats for A. aculeata. Our combined results reflect the evolutionary history and population structure of A. aculeata in Central America, highlighting the influence of South American source populations and regional barriers. These findings provide a critical foundation for conservation and breeding programs aiming to preserve the genetic diversity and adaptive potential of A. aculeata in a rapidly changing and neglected biodiversity hotspot.

Introduction: Water scarcity and uneven distribution of irrigation resources are major challenges for sustaining maize production in arid agro-ecosystems. While intercropping and conservation tillage have been individually recognized for enhancing crop productivity and resource efficiency, their integrated effects with irrigation management remain poorly understood. The long-term field platform was launched in 2015, and the trial was conducted in the northwest region in 2024, we embedded a three-factor split-plot experiment to evaluate the combined impacts of tillage (no-tillage, NT; conventional tillage, CT), planting pattern (maize-pea intercropping, IM; sole maize, SM), and irrigation regime (low, I1; medium, I2; high, I3) on maize yield, canopy photosynthetic dynamics, water-use efficiency, and photosynthetic enzyme gene expression.

Methods: No-tillage intercropping under medium irrigation (NTIMI2) consistently achieved the highest yield, exceeding CTIMI2 and NTSMI2 by 10.5% and 27.2%, respectively, mainly through increases in ear number and thousand-kernel weight. Canopylevel analyses revealed that NTIMI2 sustained higher leaf area index, leaf area duration, crop growth rate, and net assimilation rate during silking-filling, thereby extending the photosynthetic functional period. These physiological advantages translated into greater assimilate supply and efficient partitioning, supported biochemically by the upregulation of nadp-mdh and nadp-me expression during grain filling. Importantly, NTIMI2 optimized the yield-water relationship: water-use efficiency was maximized and comparable yields were maintained relative to high irrigation, but with reduced water input.

Discussion: Our findings provide mechanistic evidence that coordinated tillage and irrigation strategies regulate canopy source-sink dynamics and enzyme-mediated carbon assimilation, thereby reconciling the trade-off between yield stability and water conservation. This study highlights no-tillage intercropping with medium irrigation as a scalable pathway toward climate-resilient and water-efficient maize production in arid regions.

Introduction: The application of genetically engineered (GE) crops in pest management raises biosafety concerns among governments, the scientific community, and the public, especially with the emergence of RNA interference (RNAi)-based crops expressing insecticidal double-stranded RNA (dsRNA). These crops may pose challenges to public health, agriculture, and conservation, and they could also present risks to non-target organisms, including beneficial natural enemies of pests. Natural enemies of insects are a significant component of global biodiversity and play a crucial role in managing insect pests within agroecosystems. This study addresses the biosafety concerns associated with insect-resistant transgenic dsRNA-expressing crops, focusing on their potential unintended effects on non-target organisms, particularly natural enemies.

Methods: We combined biological and bioinformatic approaches, utilizing both food-chain delivery and animal-feeding systems, to comprehensively evaluate the potential unintended effects of exogenous insecticidal dsRNA expressed by dsAllim cotton on the biological parameters and transcriptome of the cotton-field predatory natural enemy, Orius similis.

Results: The findings indicate that dsAllim cotton had no adverse effects on O. similis, suggesting its potential safety for non-target beneficial insects. At both developmental and transcriptomic levels, dsAllim cotton showed no significant impact on O. similis.

Discussion: These results support the use of dsAllim cotton as a reference in developing regulatory frameworks for the risk assessment of RNAi crops. Together with previous research, our findings underscore the importance of conducting RNAi crop safety evaluations for non-target organisms on a case-by-case basis, with particular attention to potential off-target effects.

Introduction: Plant viruses severely affect agricultural crops and are the cause of almost half of all major plant diseases. No successful antiviral agents are now widely available for agricultural use against phytoviruses.

Methods: Micrococcus luteus was collected from the rhizosphere of faba bean and molecularly characterized via the 16S rRNA (Acc# PV650302). Soil inoculation greatly enhanced growth and induced systemic resistance to BYMV (Bean yellow mosaic virus) infection in faba bean plants grown in the greenhouse or field conditions.

Results and discussion: Soil drenching application of Micrococcus luteus resulted in a 78% decrease in the severity of the disease and a 70% decrease in viral accumulation levels. Superoxide dismutase (SOD), total chlorophyll content, antioxidant enzymes like catalase (CAT), ascorbate peroxidase (APX), and polyphenol oxidase (PPO) were all significantly increased after M. luteus treatment. The levels of oxidative stress indicators, such as malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), were shown to be much lower after M. luteus treatment. The transcripts of genes involved in pathogenesis were found to be upregulated with these alterations. It is possible to use M. luteus as a biocontrol agent, which is a practical and environmentally friendly way to protect faba bean plants against BYMV infection, since it may increase faba bean growth and generate systemic resistance against BYMV disease. Antiviral action against viral infections in plants has never been previously documented for M. luteus.

Interactions between plants and microbes that colonize them typically result in significant alterations of the host's gene expression. Such transcriptional changes include modulation of immune responses, as well as orchestrating metabolic and developmental changes locally at sites of infection and systemically in the plant. Microbes colonizing diverse hosts have evolved cross-kingdom conserved mechanisms that utilize effectors to participate directly in host transcription process and actively rewrite its transcriptome for their own benefit. In this review, we highlight the mechanisms exploited by plant-colonizing microbes to manipulate the transcriptional machinery of their hosts, including interfering with and mimicking transcription factors and co-regulators. We provide a comprehensive overview of the functionalities of effectors beyond immune suppression and conclude that controlling the host transcriptome is crucial for establishing a favorable niche for microbial plant colonizers.

Introduction: Abiotic stresses (e.g., drought, salinity, heavy metals) intensified by global environmental changes threaten plant seed germination, seedling establishment, and population persistence. Elucidating the spatio-temporal dynamics and adaptive mechanisms of seed stress responses is critical for ecological conservation and stress-resistant crop breeding, yet long-term global and regional research trends lack systematic integration.

Methods: A bibliometric analysis was conducted using CiteSpace v.6.4.R1 to process 15,627 literature records (9,042 from Web of Science; 6,585 from CNKI) spanning 1975-2024, focusing on publication dynamics, cooperation networks, intellectual base, research hotspots, and emerging frontiers.

Results: Seed-stress research evolved through three stages (initial exploration, rapid growth, steady breakthrough), with WOS and CNKI seeing annual increases of 684 and 453 articles post-2020. China led in WOS publication volume, but cooperation networks showed low connectivity. International high-cited literature centered on salinity/oxidative stress (80% reviews), while domestic research focused on staple crop stress responses and practical indicators. Post-2020, international frontiers leaned toward nanomaterials and signal transduction, and domestic frontiers prioritized cadmium pollution control and germination regulation.

Discussion: Global research presents a diverse, integrated landscape, while domestic research exhibits strong application orientation with relative fragmentation. Future research should integrate basic mechanisms with practical needs, strengthen interdisciplinary/international collaboration, and focus on combined stress adaptation and green regulatory technologies, providing theoretical and technical support for enhancing plant stress resistance and ecological security.

Introduction: Heterosis refers to the superiority of a hybrid over its parents. Existing heterosis theory has not sufficiently addressed the contribution of inbreeding at both population level and the level of individual lines within populations. The objectives of the present paper were to formalize theoretical extensions of heterosis theory to address inbreeding at multiple levels, to empirically test the theory in maize, and to provide greater clarity in the quantitative genetic interpretation of heterosis as a function of independent genetic principles of population structure and gene action.

Methods: Existing heterosis theory for biparental crosses was extended by adding terms for inbreeding within panmictic parent populations. The theory was tested with an experiment in maize with a diverse set of panmictic and inbred parents.

Results: Extended theory demonstrated that both heterosis and inbreeding depression are linear functions of inbreeding, F_ST at the population level, and f at the individual level, under a model of directional dominance. The model demonstrates that heterosis is expected to be negatively related to both midparent value and inbreeding depression within parent populations, i.e., heterosis increases as midparent value decreases and as inbreeding depression within parent populations decreases. Consistent with theoretical predictions we found that that for maize grain yield midparent value predicted 86% of heterosis in a set of crosses and parental inbreeding depression predicted 70% of variation in heterosis among crosses.

Discussion: Model extensions presented here illustrate the excess and transient nature of heterozygosity in the F₁ generation that is partially responsible for the unique performance benefit of F₁ hybrids. Mechanistically, the theory illustrates that heterosis is a function of two separate and independent mechanisms, population structure and gene action, both of which need to be considered in understanding the mechanisms of heterosis.