PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “pollination”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2026

Resolving the "Yucca queretaroensis problem": Phylogenomic analysis of Yucca reveals the identity of an enigmatic species and the origin of an obligate pollination mutualism.

PREMISE: The genus Yucca is a group of ~50 species of woody monocots endemic to the North American arid regions. Their obligate pollination mutualism with yucca moths is considered a "textbook example" of coevolution and is hypothesized to have promoted rapid diversification. However, testing this hypothesis has been difficult due to uncertainty about the placement of a rogue taxon, Yucca queretaroensis, a rare endemic of the Sierra Gorda region of central Mexico. Past work placed this species in different positions within the Agavoideae, producing starkly different age estimates for Yucca (25 to 4 million years). METHODS: We generated new sequence capture data for 353 nuclear genes and for all coding regions of the plastid genome from wild-collected plants and samples included in previous studies to provide a new phylogeny and new age estimate for Yucca. RESULTS: The data presented here suggest that Y. queretaroensis is closely related to other species of Yucca. A relaxed molecular clock analysis of the plastid genome produced an estimated age for the genus of approximately 6.8 million years. CONCLUSIONS: The results resolve a mystery that has bedeviled evolutionary biologists for decades and provide a surprisingly young estimate for the age of Yucca, suggesting rapid diversification. The past difficulties in identifying the correct placement of Y. queretaroensis appear to be the product of laboratory errors, mistakes in field identification, and frequent hybridization with co-distributed taxa. The "Yucca queretaroensis problem" reaffirms the essential role for traditional botanical tools in phylogenomics.

ASTRAL↗
PubMed2026

Inducing fixation of transgenic alleles in open-pollinated populations.

The progeny of chlorsulfuron-resistant forage rape (Brassica napus L. subsp. napus, cv. Giant) and potato (Solanum tuberosum L. cv. Iwa) plants hemizygous for a single transgenic locus were screened for transgene segregation following an application of either water or chlorsulfuron. The transgenic locus contained three transgenes conferring kanamycin resistance (NOS-NPTII-NOS), β-glucuronidase (GUS) activity (35S-GUS-OCS), and chlorsulfuron resistance (a complete acetohydroxyacid synthase gene with a proline197 to serine substitution). In the absence of the herbicide application, plants segregated for GUS activity as expected for single locus inheritance. However, the progeny of plants sprayed with chlorsulfuron exhibited a highly distorted segregation for GUS activity, with a significant excess of transgenic progeny. Inducing such biased segregation provides a simple treatment to rapidly drive the fixation of transgenic alleles to homozygosity in open pollinated populations during seed increases of new cultivars.

Alleles↗
PubMed2026

Museum specimens reveal the genomic consequences of long-term population decline in an insect pollinator.

Global insect pollinator populations are under threat, with reported declines attributed to increasing habitat loss, pesticide use, and disease. Tracking how genetic diversity has changed over time could reveal the rate and extent of these declines, and the adaptive capacity of affected species-providing an important complement to habitat-based conservation efforts. However, few studies have been able to reconstruct suitable historical baselines to link genomic changes with population change. Here, we use whole genome data from 101 museum specimens of the declining moss carder bumblebee (Bombus muscorum) collected across Britain and Ireland between 1894 and 2019 to reveal a dramatic drop in genetic diversity over the last century. We find a substantial (∼24.6%) reduction in genome-wide heterozygosity across Britain during this period. In England and Wales, where habitat fragmentation is most pronounced, we observe a 2.86-fold increase in runs of homozygosity, commensurate with population fragmentation and isolation. Our results reveal the extent to which human-induced environmental change can lead to severe decadal-scale genomic erosion in a functionally important insect. Identified using DNA from historic museum collections, our approach has widespread applicability for insect conservation and understanding the evolutionary consequences of environmental change.

Animals↗
PubMed2026

Orchard netting impacts on biodiversity leading to cascading effects at the ecosystem level.

Agriculture must ensure food production without further compromising the ecosystem functions upon which it depends. Agricultural practices should therefore avoid harming farmland biodiversity, especially of taxa that supply the key ecosystem services (e.g. pollination, pest control and nutrient uptake) that ultimately support crop production. Orchards are among the largest permanent plantations worldwide and are increasingly characterised by the spread of plastic nets used to protect fruits/nuts from either abiotic (anti-hail, anti-rain, shade nets) or biotic (exclusion nets) hazards. Despite having received little attention to date, these nets may impact natural communities, acting both as physical barriers and as drivers of habitat changes to which biota must respond. Species-level responses to netting depend on the organism's ability to enter the netted environment and successfully exploit available resources. Net-mediated ecological filtering and plastic behavioural responses may alter species interactions, leading to cascading ecological impacts that may create species-poorer 'netted communities' with simplified ecological networks. Such changes may erode biological control potential, other ecosystem functions, and overall system stability. We conducted a systematic review on the effects of protection nets on biota, and reported novel empirical evidence on anti-hail nets' impacts on communities of orchard-dwelling birds, flower-visiting insects, and rodents. In total, we identified 48 studies from the literature, however this literature was strongly biased towards apple orchards, western countries, and pest taxa. Net deployment was highly effective in deterring target pest species, in some cases regardless of their original function, as even weather-protection nets limited pest populations. Side effects on non-target taxa were also often reported, such as decreases in pollinators and natural enemies, and/or increases in secondary pests or microbial diseases. However, most assessments largely disregarded non-pest taxa and the broader ecological consequences of netting. The few studies that addressed the effects of nets at the guild/community level, including our empirical study, confirmed that orchard netting resulted in species-poor assemblages, with possible ecosystem-level consequences. We propose that future assessments should pay more attention to the indirect effects of netting on non-target taxa, and on the supply of crop-supporting ecosystem services mediated by wild species occurring in agroecosystems. Due to the trade-offs between these services and net-mediated crop protection, integrated alternatives should be tested to improve the environmental sustainability of food production and biodiversity conservation in farmed landscapes.

Biodiversity↗
PubMed2025

Genomic signature and evolutionary history of completely cleistogamous lineages in the non-photosynthetic orchid Gastrodia.

Despite a long-standing interest since Darwin's time, the genomic implications of obligate self-fertilization remain elusive. Complete cleistogamy-the obligate production of closed, self-pollinating flowers-represents an extreme reproductive strategy. Here, we present the genomic profiles and evolutionary history of two lineages of the mycoheterotrophic orchid Gastrodia, both of which independently acquired complete cleistogamy, based on detailed sampling and a combination of simple sequence repeat (SSR), multiplexed ISSR genotyping by sequencing (MIG-seq) and RNA-seq data. Our analysis reveals clear species delimitation, with no evidence of introgression between the completely cleistogamous species and their co-occurring allogamous sisters. Intriguingly, all analyses indicate that both the completely cleistogamous Gastrodia species and their allogamous sisters exhibit genetic profiles typical of self-pollinating plants. This pattern suggests that their ancestors, probably bearing allogamous flowers, had already evolved mechanisms to mitigate the deleterious effects of selfing, potentially facilitating the emergence of complete cleistogamy through benefits such as reproductive assurance, enhanced colonization ability and species reinforcement. Meanwhile, further analyses suggest that complete cleistogamy evolved very recently (possibly within the last 1000-2000 years) in these two Gastrodia lineages. Combined with the scant evidence of complete cleistogamy outside Gastrodia, our findings imply a limited and ephemeral role for complete cleistogamy in plant speciation.

Biological Evolution↗
PubMed2026

Supergene control of chiral development in mirror-image flowers.

How genes determine the development of chiral structures is a fascinating question. The reciprocal placement of female and male organs on opposite sides of mirror-image flowers promotes efficient cross-pollination. Here, we identified that in butterfly lilies, female and male organs deflect by a combination of genetically controlled chirality and gravitropism, orienting left and right with respect to an external rather than internal reference axis. We found coordinated organ placement to be controlled by a hemizygous supergene containing two candidate causal loci, MIR156-R and YUCCA-R, that are responsible for opposite female and male organ orientation, respectively. The resulting differential placement of pollen carrying the two supergene alleles on pollinators' bodies leads to their transfer to the stigmas of flowers with opposite handedness and maintenance of the reproductive polymorphism.

Alleles↗
PubMed2026

Fructophilic lactic acid bacteria as a window into multi-scale convergent evolution.

Fructophilic lactic acid bacteria (FLAB) are a group of lactic acid bacteria with unique growth characteristics, that is, poor growth on glucose. Their growth is enhanced in the presence of fructose or external electron acceptors. These organisms inhabit fructose-rich environments such as flowers, fruits, and pollinating insects, particularly honey bees. Apilactobacillus spp. and Fructobacillus spp. are representatives of FLAB, although they belong to phylogenetically distant clades. These organisms commonly possess markedly small genomes with a low number of coding DNA sequences. Furthermore, their genomes are characterized by a markedly reduced number of genes involved in carbohydrate transport and metabolism. Genome reduction in FLAB reflects convergent adaptation to fructose-rich environments rather than general genome streamlining. The two distinct FLAB genera, Fructobacillus and Apilactobacillus, independently lost more than 100 genes in statistically similar orders. In contrast, genes involved in carbohydrate and amino acid metabolism exhibited reversed orders of loss between the two genera. Furthermore, FLAB genomes lack an intact bifunctional alcohol/aldehyde dehydrogenase gene (adhE), which causes their poor growth on glucose. A comparative genomic study suggested the evolutionary process underlying adhE gene decay during adaptation to the fructose-rich environments, including pollinating insects. In conclusion, FLAB represent a unique example of habitat-driven convergent reductive evolution that can be investigated across multiple biological scales - from individual genes to whole genomes - in the diverse LAB group with a wide range of habitats, and partially share the fructophilic evolution with eukaryotic yeasts found in fructose-rich habitats.

Fructose↗
PubMed2026

Phylotranscriptomics Allows Distinguishing Major Gene Flow Events from Incomplete Lineage Sorting in Rapidly Diversifying Mimetic Orchids (Genus Ophrys).

Ophrys orchids (or bee orchids) provide an outstanding example of a plant adaptive radiation. Over the last 5 million years, this genus has diversified into hundreds of taxa as a result of its unconventional pollination strategy, known as "sexual swindling". However, the rapid and substantial diversification of this genus, combined with its capacity for hybridization and large genome size, poses significant challenges in addressing its systematics. We used phylotranscriptomics as a genome complexity reduction technique to infer the phylogenetic relationships among Ophrys main lineages. More than seven thousand gene trees enabled us to determine the relative contributions of gene flow and incomplete lineage sorting (ILS) in Ophrys evolution. First, we propose a new phylogenetic hypothesis for the genus with an unprecedented resolution that largely confirms the relationships between the main Ophrys lineages, but also provides new insights within each subgenera. By combining phylogenetic network inference with introgression analyzes based on gene tree topologies and branch lengths, we then show that the numerous phylogenetic incongruences among gene tree topologies result from a pervasive background of ILS, over which stand out several well-supported, ancient and potentially adaptive gene flow events between lineages. These major gene flow events provide a new perspective on the evolution of the Ophrys genus and its pollination, questioning previous hypotheses inferred without considering its reticulate evolution, and providing a better understanding of discrepancies observed among previous phylogenetic studies of the genus.

Orchidaceae↗
PubMed2024

Molecular identification of Hymenopteran insects collected by using Malaise traps from Hazarganji Chiltan National Park Quetta, Pakistan.

The order Hymenoptera holds great significance for humans, particularly in tropical and subtropical regions, due to its role as a pollinator of wild and cultivated flowering plants, parasites of destructive insects and honey producers. Despite this importance, limited attention has been given to the genetic diversity and molecular identification of Hymenopteran insects in most protected areas. This study provides insights into the first DNA barcode of Hymenopteran insects collected from Hazarganji Chiltan National Park (HCNP) and contributes to the global reference library of DNA barcodes. A total of 784 insect specimens were collected using Malaise traps, out of which 538 (68.62%) specimens were morphologically identified as Hymenopteran insects. The highest abundance of species of Hymenoptera (133/538, 24.72%) was observed during August and least in November (16/538, 2.97%). Genomic DNA extraction was performed individually from 90/538 (16.73%) morphologically identified specimens using the standard phenol-chloroform method, which were subjected separately to the PCR for their molecular confirmation via the amplification of cytochrome c oxidase subunit 1 (cox1) gene. The BLAST analyses of obtained sequences showed 91.64% to 100% identities with related sequences and clustered phylogenetically with their corresponding sequences that were reported from Australia, Bulgaria, Canada, Finland, Germany, India, Israel, and Pakistan. Additionally, total of 13 barcode index numbers (BINs) were assigned by Barcode of Life Data Systems (BOLD), out of which 12 were un-unique and one was unique (BOLD: AEU1239) which was assigned for Anthidium punctatum. This indicates the potential geographical variation of Hymenopteran population in HCNP. Further comprehensive studies are needed to molecularly confirm the existing insect species in HCNP and evaluate their impacts on the environment, both as beneficial (for example, pollination, honey producers and natural enemies) and detrimental (for example, venomous stings, crop damage, and pathogens transmission).

Humans↗
PubMed2026

Spatial inheritance patterns across maize ears are associated with alleles that reduce pollen fitness.

Often, more pollen grains land on recipient flowers than there are ovules to fertilize. Consequently, the haploid male gametophyte engages in post-pollination competition, one way that pollen genotype can influence inheritance. The maize (Zea mays subsp. mays L.) inflorescence (ear), with its elongated stigma and style structures (silks), has a conspicuous spatial heterogeneity, with longer silks at the base of the ear than at the apex. To evaluate the hypothesis that alleles with reduced pollen fitness influence the spatial distribution of progeny genotypes along the ear, we developed an updated phenotyping platform that maps fluorescently marked mutant (Ds-GFP) kernel phenotypes on the ear via an implementation of the Faster R-CNN machine vision model (EarVision.v2) and a statistical pipeline that evaluates the relationship between kernel position and transmission ratio (EarScape). Our dataset (1384 ears) represents 58 Ds-GFP insertion alleles. None of the 48 alleles with Mendelian inheritance showed any significant spatial trend. In contrast, 50% of alleles with a pollen-specific transmission defect (5/10) exhibited significant spatial effects. An insertional mutant of the gene encoding a putative actin-binding protein, base-to-apex gradient1* (bag1*), is associated with decreased mutant transmission at the ear base relative to the apex. Surprisingly, a mutant allele of another pollen-expressed gene (Zm00001eb236740) generates the opposite trend, decreased mutant transmission toward the ear apex; and two mutant alleles of the sperm cell attachment factor gamete expressed2 (gex2) can produce ears with transmission highest at both base and apex. We conclude that pollen fitness mutants cause unexpectedly diverse spatial patterns of progeny genotypes.

Zea mays↗
PubMed2025

Quantifying genetic and genotypic gain gaps in Eucalyptus: the hidden cost of ignoring inbreeding and dominance.

Understanding the mating system of Eucalyptus species is necessary to accurately estimate genetic parameters and improve breeding programs. Eucalyptus species often exhibit mixed mating systems, leading to complex relationships among progenies. Traditional tree breeding programs that assume a half-sibling relationship for open-pollinated (OP) trials may overestimate genetic gains by neglecting the effects of inbreeding and dominance. This study focuses on Eucalyptus pellita, a species with a mixed mating system, to quantify the impact of selfing and dominance on breeding strategies. We simulated OP trial growth data for 100 randomly selected families in a randomized complete block design, using published estimated parameters for diameter at breast height (DBH). Our analysis indicated that marker-based models, particularly those incorporating dominance effects, provide more accurate genetic parameter estimates and larger predicted genetic gains than pedigree-based models. These results reveal pronounced genetic and genotypic gain gaps when traditional models are employed, underscoring the imperative for integrating dominance-informed genomic selection strategies. Thus, our study provides essential guidance for optimizing breeding programs to sustainably enhance productivity and genetic quality in Eucalyptus plantations.

Eucalyptus↗
PubMed2024

Variable resource allocation pattern, biased sex-ratio, and extent of sexual dimorphism in subdioecious Hippophae rhamnoides.

Evolutionary maintenance of dioecy is a complex phenomenon and varies by species and underlying pathways. Also, different sexes may exhibit variable resource allocation (RA) patterns among the vegetative and reproductive functions. Such differences are reflected in the extent of sexual dimorphism. Though rarely pursued, investigation on plant species harbouring intermediate sexual phenotypes may reveal useful information on the strategy pertaining to sex-ratios and evolutionary pathways. We studied H. rhamnoides ssp. turkestanica, a subdioecious species with polygamomonoecious (PGM) plants, in western Himalaya. The species naturally inhabits a wide range of habitats ranging from river deltas to hill slopes. These attributes of the species are conducive to test the influence of abiotic factors on sexual dimorphism, and RA strategy among different sexes. The study demonstrates sexual dimorphism in vegetative and reproductive traits. The sexual dimorphism index, aligned the traits like height, number of branches, flower production, and dry-weight of flowers with males while others including fresh-weight of leaves, number of thorns, fruit production were significantly associated with females. The difference in RA pattern is more pronounced in reproductive traits of the male and female plants, while in the PGM plants the traits overlap. In general, habitat conditions did not influence either the extent of sexual dimorphism or RA pattern. However, it seems to influence secondary sex-ratio as females show their significant association with soil moisture. Our findings on sexual dimorphism and RA pattern supports attributes of wind-pollination in the species. The observed extent of sexual dimorphism in the species reiterates limited genomic differences among the sexes and the ongoing evolution of dioecy via monoecy in the species. The dynamics of RA in the species appears to be independent of resource availability in the habitats as the species grows in a resource-limited and extreme environment.

Hippophae↗
PubMed2025

Fine mapping of the dominant female sterility gene and novel model of hybrid seed production in cabbage (Brassica oleracea L. var. capitata).

Hybrid breeding based on male sterility requires the removal of male parents, which is time- and labor-intensive; however, the use of female sterile male parent can solve this problem. In the offspring of distant hybridization between Brassica oleracea and Brassica napus, we obtained a mutant, 5GH12-279, which not only fails to generate gynoecium (thereby causing female sterility) but also has serrated leaves that could be used as a phenotypic marker in seedling screening. Genetic analysis revealed that this trait was controlled by a single dominant gene. Further analysis revealed that Bo2g005230, an orthologous gene of LATE MERISTEM IDENTITY1 (LMI1) in Arabidopsis, was predicted as the candidate gene and was renamed BoLMI1c. Sequence analysis revealed that homoeologous exchange (HE) occurred within the BoLMI1c gene body of 5GH12-279, which resulted in the generation of a novel fusion transcript. Two pairs of primers, N5230-1F/1R and N5230-2F/2R, were designed and successfully used for the identification of different genotypes of BoLMI1c. Transcriptome analysis revealed that BoLMI1c orchestrates the expression of several related biological processes and transcription factors. Furthermore, we found that self-pollination with mason bees produced no seeds in 5GH12-279, whereas the near-isogenic line 5GH12-170 produced seeds that were normal. Therefore, a new labor-saving hybrid seed production system with no need to remove the male parents, which is especially important for mechanized harvest in the future, has been proposed. Our study provides a valuable source of dominant female sterility and suggests the potential utilization of the female sterile line in hybrid breeding for mechanized harvest.

Plant Infertility↗
PubMed2026

The Adaptive Roles of Active Transposable Elements in Insect Hosts.

Active transposable elements (TEs) are capable of generating new insertions in genomes and have historically been viewed as genomic parasites due to their largely detrimental or neutral effects. However, emerging evidence suggests that these elements also play a crucial role in driving adaptive evolution in insects. This mini-review synthesizes recent findings on how active TEs contribute to insect adaptation through various mechanisms, including regulation of gene expression, structural variation, and epigenetic effects. Notable examples of adaptation driven by active TEs include their roles in insecticide resistance, morphological adaptations, tolerance to harsh climates, and antiviral immune responses. We argue that while host silencing mechanisms, such as the piRNA pathway, tightly regulate TE activity to minimize harmful effects, the context-dependent activation of active TEs can generate beneficial genetic variation that enhances insect adaptations to anthropogenic and climatic pressures. Future research that integrates long-read sequencing, single-cell omics, and gene editing techniques will provide a robust mechanistic foundation for understanding the adaptive significance of active TEs in insects, with important implications for pest management, pollinator protection, and evolutionary biology.

Journal Article↗
PubMed2026

Heat stress in cereal crops: reproductive development and grain filling.

Increasingly frequent extreme heat events threaten cereal production and food security under a changing climate. The reproductive-to-grain formation continuum of cereals is particularly vulnerable to elevated temperatures, as heat stress disrupts developmental processes from inflorescence formation and fertilization to grain filling and quality establishment. These disruptions reduce reproductive success, impair yield formation, and compromise grain quality. A comprehensive understanding of the developmental, physiological, molecular, and genetic basis of cereal heat tolerance is therefore essential for developing climate-adapted crops. This review summarizes recent advances in understanding heat stress during cereal reproduction and grain filling across major cereal crops. We first discuss how heat stress affects sequential developmental processes, including inflorescence development, gametophyte development, flowering and pollination, fertilization, and grain filling. We then integrate emerging evidence on cross-cutting mechanisms that connect stage-specific heat responses, focusing on hormonal and redox homeostasis, carbohydrate metabolism and source-sink coordination, proteostasis and endomembrane organization, and genome stability and multilayered gene regulation. Finally, we summarize the genetic basis of cereal heat tolerance by highlighting genetic determinants, favorable alleles, and their potential applications in breeding. We further discuss current bottlenecks and future opportunities for breeding heat-tolerant cereals.

Cereals↗
PubMed2026

Proteome-level evidence that tebuconazole, both alone and in interaction with thiacloprid, affects epigenetic events in bumblebee heads.

Tebuconazole, a widely used ergosterol biosynthesis-inhibiting fungicide, can affect nontargets, especially when combined with insecticides. We employed label-free quantitative proteomics to investigate the effects of long-term exposure to sublethal concentrations (100 μg/L) of tebuconazole, either by itself or alongside the neonicotinoid thiacloprid (100 μg/L), on the heads of Bombus terrestris workers. A Bayesian factor power analysis revealed that the experiment produced conclusive proteomic results. Tebuconazole treatment revealed eleven differentially abundant proteins, which increased elevenfold with thiacloprid. The proteins that changed in the same direction in both treatments suggest the occurrence of epigenetic events because they are involved in histone trimethylation (H3K4me3), pre-mRNA processing, and folate (vitamin B9) metabolism. Following co-exposure, the abundance of histone H2A.V and its associated proteins was affected. Two important detoxification-related proteins, CYP6BE1 and CYP6AQ1 (honey bee homologs), were identified, as well as proteins that suggest hormonal and neurotoxic effects. Overall, this study suggests that tebuconazole affects key epigenetic processes in bumblebee heads at the proteome level, though this was not confirmed at the biological level or through orthogonal methods. The tested chemicals were previously found to affect trimethylations, but not H3K4me3. We suggest analyzing the different trimethylations, their interplay, and associated hallmarks, such as folate levels. SIGNIFICANCE: The effects of pesticides and their combinations on organisms can be unexpected until they are examined using modern, complex methods. High-throughput proteomics can provide data on important biochemical processes affected by pesticides, offering a different perspective to that at the expression level. Despite their low acute toxicity, a group of fungicides that inhibit (ergo)sterol biosynthesis (EBI or SBI) are considered dangerous to pollinators, including bumblebees. This is due to the increasing toxicity of insecticides through the inhibition of cytochrome P450 detoxification enzymes. We found that tebuconazole had a similar effect on epigenetic events when used alone or in combination with the insecticide thiacloprid. Key proteins suggest that H3K4 histone trimethylation (H3K4me3) was impacted. To our knowledge, this expands the existing evidence suggesting that tebuconazole/triazole fungicides affect histone trimethylation H3K27me3. Since literature shows that thiacloprid affects H3K9me3, it is possible that thiacloprid and tebuconazole interact in these epigenetic events that affect each other. Overall, our results suggest that tebuconazole affects proteins involved in histone trimethylation, pre-mRNA processing, and folate metabolism. These are all hallmarks of epigenetic processes and were further extended by the co-exposure of tebuconazole and thiacloprid to more differently abundant proteins. Additionally, the results provide data on cytochrome P450s of the CYP6 family, which act as detoxifying proteins, as well as proteins that indicate hormonal and neurotoxic effects in bumblebee heads. Finally, the results of the Bayesian power analysis confirmed the meaningfulness of the proteomic data analyzed in this study. If the new findings obtained at the proteome level are verified by different methods, the full extent of the side effects of tebuconazole can be revealed.

Animals↗
PubMed2026

Mechanistic analysis of rice caryopsis morphogenesis regulated by exogenous hormones and related precursor substances under blue light conditions.

Rice caryopsis morphogenesis is regulated by light signals and hormonal networks. However, the mechanism by which exogenous hormones and related precursor substances modulate rice caryopsis morphogenesis under blue light remains elusive. In the present study, we aimed to elucidate the molecular mechanisms underlying the regulatory effects of exogenous phytohormones and related precursor substances on caryopsis development at 10&#xa0;days after pollination (10 DAP) in the japonica rice cultivar 'Chujing 27' under blue light conditions. Results showed that tryptamine treatment increased caryopsis cell volume, thereby significantly driving caryopsis expansion; meanwhile, it markedly enhanced the activities of TDC and TAA, the key rate-limiting enzymes mediating the conversion of tryptophan to auxin, leading to a significant elevation in endogenous auxin content (P&#xa0;<&#xa0;0.05). In comparison, exogenous auxin treatment significantly boosted carbohydrate accumulation and the activities of associated metabolic enzymes (P&#xa0;<&#xa0;0.05). Integrated transcriptomic and metabolomic analyses revealed that tryptamine treatment led to significant enrichment of the starch and sucrose metabolic pathway, and drove the coordinated enhancement of carbon metabolic flux and auxin biosynthesis by upregulating key auxin biosynthetic genes (e.g., TAA1) and repressing auxin oxidative degradation. Genes Os04g0531100, Os03g0266100 and Os11g0221200 identified by weighted gene co-expression network analysis (WGCNA) may serve as important candidate targets regulating rice caryopsis morphology and physiological traits under blue light conditions. This study first uncovers the critical function of the "tryptamine-auxin axis" in regulating rice caryopsis development under blue light, laying a theoretical foundation for regulating caryopsis morphogenesis via exogenous hormones and their precursors.

Oryza↗