Nekemias grossedentata, a perennial woody vine and the primary source of vine tea, is valued for its medicinal and edible properties. Its leaves contain key bioactive compounds, such as flavonoids (notably dihydromyricetin) and polyphenols, which determine the core quality of vine tea. However, overexploitation threatens wild populations, leading to germplasm resource depletion and loss of genetic diversity, underscoring the urgent need for effective conservation and breeding strategies. Therefore, this study aimed to clarify the genetic diversity, construct a core germplasm collection, and screen elite accessions to support the conservation and sustainable utilization of N. grossedentata. Using principal component analysis on 10 leaf phenotypic traits from 190 samples across eight production regions, this study identified total leaf flavonoid content (contribution rate: 0.810) as the key factor influencing phenotypic variation. Based on transcriptome data previously obtained by our group from different tissues, 25,009 EST-SSR primer pairs were developed, from which 18 stable and polymorphic EST-SSR markers were screened. Utilizing these markers to assess population and individual genetic diversity revealed a high level of genetic diversity in N. grossedentata: average Shannon's diversity index (0.880), expected heterozygosity (0.497), and observed heterozygosity (0.194). Based on these analyses, a core germplasm collection comprising 19 representative accessions from eight geographic origins was constructed. Finally, based on the catechin quality index (CQI) of these 19 core accessions, six elite accessions were selected: GD-10, GX-13, GX-15, GX-18, GX-21, and HN-31. These accessions exhibit high genetic diversity, high CQI (>100), and high total flavonoid content (>20%), making them suitable for direct use as core parental materials. This study provides the first systematic evidence of high genetic diversity in N. grossedentata resources, successfully establishing a core germplasm collection while identifying elite accessions to offer a scientific foundation for conservation, evaluation, and breeding utilization.

The initial carbon-to-nitrogen (C/N) ratio is a fundamental parameter for aerobic composting, with a generally recommended optimal range of 25:1 to 30:1. However, in practical applications, the optimal C/N ratio often deviates from the recommended value. We attribute this discrepancy to the limitations of traditional stoichiometric methods in assessing the bioavailability of carbon and nitrogen sources. This study investigated how carbon bioavailability governs composting efficiency and product quality. Laboratory-scale aerobic composting experiments were conducted using six types of raw crop straws and two physically pretreated straws, representing a biodegradability gradient. Results demonstrated that carbon bioavailability significantly modulated the composting performance. Substrates rich in labile carbon pool (LCP), such as wheat straw and extruded cassava plant residue, demonstrated superior thermogenesis, humification, and seed germination indices compared to those dominated by recalcitrant carbon pool (RCP), such as untreated cassava plant residue. Principal component analysis confirmed a strong positive correlation between LCP content and key quality indicators. Microbiological analysis revealed that carbon source variations shaped bacterial succession: Bacteroidota abundance correlated positively with LCP, driving rapid initial degradation, whereas Pseudomonadota were more abundant in RCP-rich treatments, suggesting a role in complex polymer breakdown. This study confirmed that carbon bioavailability, rather than the bulk C/N ratio alone, is a critical limiting factor. This finding logically extends to the role of nitrogen bioavailability, suggesting that a “biochemical C/N ratio”—accounting for the lability of both carbon and nitrogen—could be a more accurate predictor of aerobic composting performance.

Ginkgo biloba is a singular and relict gymnosperm indigenous to China. Its distinctive fleshy episperm is rich in unique metabolites, ginkgolic acids, which protect the developing seed from biotic stresses. The unique nature of the tissue and its metabolites has made it highly challenging to elucidate the molecular and cellular mechanisms governing ginkgolic acid biosynthesis and regulation. In this study, we performed the mass spectrometry imaging of G. biloba seed, revealing that ginkgolic acids primarily accumulate in the secretory cavities of the episperm. We constructed a single-cell expression atlas of the G. biloba episperm and identified seven cellular types: meristem cells, subepidermal cells, lignified cells, trancheid cells, parenchymal cells, secretory cavity cells, and epidermis cells. Based on the analysis of upregulated gene expression in secretory cavity cells, pseudotime analysis of cell differentiation, and gene expression trajectory analysis, we precisely identified the key enzyme-encoding genes highly associated with ginkgolic acid biosynthesis. This approach elucidated the cellular and molecular mechanisms underlying secretory cell differentiation, secretory cavity formation, and ginkgolic acid biosynthesis and accumulation in response to exogenous jasmonic acid induction. By constructing a molecular interaction network, it was determined that the GbWRKY35, encoded by Gb_25334, is the core transcription factor. We further identified the signaling proteins that interact with GbWRKY35, confirming its central positive regulatory role in ginkgolic acid biosynthesis. As a core transcription factor, GbWRKY35 regulates ginkgolic acid biosynthesis through stimulating the expression of GbAAE16. This study provides the first spatially resolved investigation into the molecular and cellular regulatory mechanisms of ginkgolic acid biosynthesis in the episperm under jasmonic acid induction.

Nekemias grossedentata (Hand.-Mazz.) J. Wen & Z. L. Nie is a medicinal and edible plant with a high dihydromyricetin (DHM) content in its bud tips. Vine tea made from its bud tips has served as a health tea and Chinese herbal medicine for nearly 700 years. However, the molecular mechanisms underlying the high DHM content in N. grossedentata bud tips remain inadequately elucidated. This study conducted qualitative and quantitative analyses of bud tip flavonoids utilizing HPLC and targeted metabolomics. Core genes influencing the substantial synthesis of DHM in N. grossedentata were identified through integrated transcriptome and metabolome analyses. The results revealed that 65 flavonoid metabolites were detected in bud tips, with DHM as the predominant flavonoid (37.5%), followed by myricetin (0.144%) and taxifolin (0.141%). Correlation analysis revealed a significant positive correlation between NgF3′5′H3 expression and DHM content. Co-expression analysis and qRT-PCR validation demonstrated a significant positive correlation between NgMYB71 and NgF3′5′H3, with consistent expression trends across three periods and four tissues. Consequently, NgF3′5′H3 and NgMYB71 were identified as core genes influencing the substantial synthesis of DHM in N. grossedentata. Elevated NgMYB71 expression in bud tips induced high NgF3′5′H3 expression, facilitating extensive DHM synthesis in bud tips. Molecular docking analysis revealed that NgF3′5′H3 had a strong binding affinity for taxifolin. NgF3′5′H3 was the pivotal core node gene in the dihydromyricetin biosynthesis pathway in N. grossedentata and was highly expressed in bud tips. The strong specific binding of NgF3′5′H3 to dihydromyricetin precursor metabolites catalyzed their conversion into DHM, resulting in higher DHM contents in bud tips than in other tissues or plants. This study aimed to elucidate the molecular mechanisms underlying the substantial synthesis of DHM in N. grossedentata, providing a theoretical foundation for enhancing DHM production and developing N. grossedentata resources.

Vitamin B6 is an essential coenzyme involved in various metabolic processes critical for plant growth and development. However, its biosynthesis and regulatory mechanisms remain poorly understood in the ancient gymnosperm Ginkgo biloba. In this study, we identified two members of the PDX2 gene family (Gb_34755 and Gb_34990) through genome-wide analysis and characterized their molecular and functional properties. Bioinformatic analysis revealed distinct physicochemical traits and subcellular localizations, with Gb_34755 predicted in the cytoplasm and Gb_34990 in both chloroplasts and cytoplasm. Both proteins contain the glutaminase-related PLN02832 domain, indicating involvement in VB6 biosynthesis. Chromosomal mapping placed the genes in transcriptionally active regions on chromosomes 6 and 9. Phylogenetic analysis showed close evolutionary relationships between Ginkgo PDX2 genes and those in ferns and gymnosperms, distinct from angiosperms. Promoter analysis revealed differential enrichment of cis-elements: Gb_34990 harbored low-temperature and salicylic acid-responsive elements, while Gb_34755 showed motifs related to development. Gene expression profiling indicated significant upregulation (p < 0.05) of both genes during the late developmental stages of Ginkgo kernels, coinciding with peak VB6 content. Functional validation via transient overexpression in Nicotiana benthamiana confirmed a positive regulatory role, with VB6 levels increasing from 3.38 μg/g to 12.17 μg/g (p < 0.05). This study provides the first comprehensive functional analysis of the PDX2 gene family in Ginkgo and confirms their critical role in VB6 biosynthesis. These findings enhance our understanding of vitamin metabolism in gymnosperms and present promising targets for metabolic engineering in plants.

Background: β-ketolipoyl coenzyme A synthase (KCS) is an essential limiting catalyst involved in carbon chain elongation during fatty acid biosynthesis, characterized by strict substrate specificity. C18:1 (oleic acid) plays a vital role in cell membranes and is essential for nutrient storage and stress defense. There are indications of significant accumulation and rapid synthesis of C18:1 during the early growth stages of Ginkgo biloba L. episperm. The KCS gene family in G. biloba has yet to be analyzed, and the role of KCS in oleic acid synthesis remains unexplored. Methods: In this study, this issue was investigated using transcriptomic and metabolomic data, bioinformatics analysis to screen a key gene from the KCS gene family, and dual validation using yeast and Arabidopsis thaliana expression systems to probe its function. Results: A total of 11 members of the GbKCS gene family were identified, and the dynamics of these genes were analyzed during exocarp development in the G. biloba genome. Among them, the gene designated GbKCS7 showed a highly direct association with the content of C18:1. Heterologous expression of GbKCS7 in yeast increased C18:1N12 and C18:1 content by 3.18-fold and 2.07-fold, respectively. Overexpression of GbKCS7 in Arabidopsis showed that C18:1 was increased by 27.70% and 31.43% in GbKCS7-OE-1 and GbKCS7-OE-2 strains, correspondingly, in juxtaposition to the non-transgenic plants. In addition, the content of VLCFAs increased to varying degrees. Conclusions: These outcomes offer important insights for investigating the role of KCS genes in fatty acid synthesis to further improve G.biloba resistance.

Cyperus rotundus L. (purple nutsedge) is an invasive weed with medicinal value, but its genomic resources are limited, hindering research on bioactive compound biosynthesis and herbicide resistance mechanisms. This study presents the first telomere-to-telomere (T2T) genome assembly of C. rotundus, generated using Illumina, PacBio, and Hi-C technologies. The genome consists of 55 pseudochromosomes (285.57 Mb, N50 = 5.64 Mb), with 58.31% repetitive sequences and 25,289 protein-coding genes. Phylogenetic analysis indicates that C. rotundus diverged from Cyperus esculentus around 4.75 million years ago and experienced a whole genome duplication (WGD) event approximately 5.4 MYA. Chromosomal evolution analysis revealed fusion and fission events, offering insights into karyotype evolution in the Cyperaceae family. Integrated transcriptomic and metabolomic analyses identified sesquiterpenoids and monoterpenoids as primary terpenoid classes, with higher accumulation in tubers and roots. We predicted CroTPS11-14 as a key enzyme in cyperone precursor biosynthesis and identified 10 transcription factors potentially regulating sesquiterpenoid biosynthesis. Additionally, multiple herbicide target genes were found to have multiple copies, such as acetyl-CoA carboxylase (ACCase), acetolactate synthase (ALS), phytoene desaturase (PDS), and protoporphyrinogen oxidase (PPO). Gene family expansion analysis revealed a large number of non-target resistance genes and adaptive genes related to flooding stress, such as superoxide dismutase (SOD), Flavoprotein oxidoreductases (FMN), Glycosyltransferases (GT1), Calcium-dependent protein kinase (CPK15), sucrose synthase (SUS1), and LRR receptor-like kinases. Further in vitro enzyme activity assays and q-PCR revealed that these genes may play roles in herbicide resistance and environmental adaptability. This research offers a high-quality genomic resource for C. rotundus, shedding light on its medicinal compound biosynthesis and herbicide resistance mechanisms, and providing valuable insights for molecular breeding, medicinal development, and sustainable weed control strategies.

Background: The PDX2 gene serves as a critical catalytic component in vitamin B6 (VB6) biosynthesis pathways and plays pivotal regulatory roles in plant growth. Methods: To investigate the metabolic regulation of PDX2 (GbPDX2) from Ginkgo biloba in VB6 biosynthesis during kernel development, we successfully cloned this gene and conducted systematic expression profiling through qRT-PCR across multiple tissues and developmental stages. Results: Bioinformatic characterization revealed that GbPDX2 contains a 765-bp coding sequence encoding a 254-amino acid polypeptide. The encoded protein displays typical hydrophilic properties (average hydrophobicity index: −0.32) and was predicted to be an unstable cytosolic protein (instability index: 45.7) lacking signal peptides or transmembrane domains with cytoplasmic localization. Phylogenetic analysis demonstrated that GbPDX2’s closest evolutionary relationship was with its ortholog in Picea sitchensis, which had an amino acid sequence similarity of 83.7% with spruce PsPDX2. Tissue-specific expression analysis revealed a gradient expression profile of Kernel > Exocarp > Leaves > Stems > Roots. The expression level in kernels was significantly higher than that in other tissues (19.7 times that in roots, 8.3 times that in stems, and 5.9 times that in leaves; p < 0.01), with peak transcript levels observed in mature kernels. HPLC quantification established a strong positive correlation between GbPDX2 expression dynamics and VB6 accumulation patterns during kernel maturation (r = 0.92, p < 0.01), and the peak period of VB6 reached 288.9 ± 7.1 μg/g. Conclusions: Our findings provide the first experimental evidence that GbPDX2 spatiotemporally regulates VB6 biosynthesis in ginkgo kernels, offering novel insights into the evolutionary adaptation of vitamin metabolism in gymnosperms.

Ampelopsis grossedentata, native to southern China, is renowned for its therapeutic and nutritional benefits, often called the “king of flavonoids” due to its high dihydromyricetin content. The dried stems, leaves, and shoot tips, known as “vine tea,” are consumed as a health beverage and traditional remedy for colds and fever. In this study, we assembled a near-complete reference genome of A. grossedentata spanning 555.42 Mb, where Hi-C-based correction resolved 18 out of its 20 chromosomes into gap-free assemblies. The genome, anchored to 20 chromosomes, comprises 44 contigs with an N50 of 21.93 Mb and 28 scaffolds with an N50 of 30.45 Mb, containing 25,999 protein-coding genes and 62.62% repetitive sequences. The A. grossedentata experienced two whole-genome duplication (WGD) events: a whole-genome triplication event shared by the core angiosperms and a WGD event shared with Vitaceae family. Through transcriptome-metabolome integrated analysis, AgF3H1 gene was identified as playing a crucial role in the biosynthesis of dihydromyricetin (a flavanonol) in A. grossedentata. The AgF3H gene is essential for converting pentahydroxy flavones to dihydromyricetin within the flavonoid biosynthesis pathway in A. grossedentata, as confirmed by molecular docking results. Thus, we postulate that AgF3H1 serves as a pivotal regulatory gene in the dihydromyricetin biosynthetic pathway of A. grossedentata. These insights offer valuable genetic resources for the molecular breeding of A. grossedentata and enhance our comprehension of Vitaceae genomic evolution and flavonoid biosynthesis regulation in medicinal and nutritional plants.

Anthocyanin is an important pigment that affects plant color change. In this study, the color parameters and anthocyanin content of Ginkgo biloba seed exocarp at different periods were measured, and it was determined that the a* value (redness value) of the seed exocarp was closely related to the color change occurring during the development of the seed exocarp, and the anthocyanin content in the seed exocarp showed an increasing trend. The molecular mechanism of anthocyanin biosynthesis in Ginkgo biloba seed exocarp is still unclear. In order to further understand the molecular mechanism of color change in Ginkgo biloba seed exocarp, the regulation mechanism and accumulation mode of anthocyanin in the seed exocarp at three different periods were analyzed using transcriptomic and metabolomic. A total of four key anthocyanins were screened from the metabolome, including three kinds of Cyanidin 3-arabinoside, Malvidin 3-glucoside and Cyanidin 3-sambubioside 5-glucoside with increased content. Among them, Cyanidin 3-arabinosidehad a strong correlation with the a* value (PCC = 0.914), which have a great influence on the color change of the seed exocarp, and Delphinidin 3-O-3″,6″-O-dimalonylglucoside with decreased content might jointly affect the formation of exocarp color. The transcriptome data show that among the structural genes, ANS (Gb_33402) had the highest correlation with Cyanidin 3-arabinoside (PCC = 0.9217) and in GbANS, only Gb_33402 showed an upregulated expression trend in the three stages of seed exocarp development, which suggesting that it plays an important role in anthocyanin accumulation in the seed exocarp and it may be the key structural gene affecting the formation of seed exocarp color. Among the transcription factors, the differential expression of most transcription factors (MYB, bHLH, b-ZIP, NAC, WDR and AP2/ERF) may jointly affect the formation of seed exocarp color by promoting anthocyanin accumulation. This study elucidates the main anthocyanins that cause the color change of the seed exocarp of Ginkgo biloba and reveals the molecular regulation mechanism of anthocyanins at different developmental stages of the seed exocarp. It provides a theoretical basis and insights for understanding the color change of Ginkgo biloba seed exocarp.

Ginkgolic acids is a sort of phenolic lipid compound predominantly enriched in the episperm of Ginkgo biloba. Ginkgolic acids exhibits cytotoxicity and allergenic effects, providing a defense against a variety of biotic stresses from insects, fungus, and bacteria. Ginkgolic acids specifically accumulates in the episperm of Ginkgo biloba, providing the seeds with a unique defence mechanism against biotic stresses and ensuring their survival. However, the regulatory mechanism of ginkgolic acids (GA) biosynthesis remains unclear. In this study, we performed combined metabolome and transcriptome analysis to identify key genes and metabolites involved in ginkgolic acids biosynthesis. The ginkgolic acids, including 6-[(8Z)-Pentadecenyl]-salicylic acid (GA 15:1), 2-hydroxy-6-pentadecylsalicylic acid (GA 15:0) and 5-(8-Pentadecenyl)-1, 3-benzenediol (BL 15:1), as well as their precursors, palmitic acid (FA 16:0) and palmitoleic acid (FA 16:1) were detected and showed regular changes in content during episperm development. From co-expression profiles of the differentially expressed genes, three enzyme-encoding genes including one ketoacyl-CoA synthase gene (GbKCS5) and two long-chain acyl-CoA synthase genes (GbAcsl4 and GbAcsl7) positively associated to GA 15:1 were identified as key candidates. Furthermore, co-expression analysis demonstrates that these genes might be negatively and positively regulated by the bHLH and MYB transcription factors, respectively. In addition, the endogenous jasmonic acid (JA) level in Ginkgo episperm were strongly associated with candidate ginkgolic-acid-related genes and metabolites. And JA may be an important regulator involved in ginkgolic acids biosynthesis. Exogenous JA treatment improved the expression of the GbMYB14, GbKCS5, GbAcsl4 and GbAcsl7 genes, while inhibited most Gb-bHLH genes, which was proposed to be significantly increased ginkgolic acids content. Our findings indicate that application of JA in the Ginkgo episperm can alter the expression levels of genes associated with ginkgolic acids and increase the production of ginkgolic acids. This provides a new insight for research on the regulation and utilization of ginkgolic acids.

Given the heterogeneity of raw materials, the diversity of composting processes, and the complexity of biological transformations, systematically exploring the critical role of the initial carbon-to-nitrogen (C/N) ratio in the aerobic composting of agricultural residues is challenging within a single experimental study. This study employs meta-analysis to investigate this role. Statistical analysis of 192 scholarly articles confirmed that most studies adhere to the recommended optimal initial C/N range of 25 and 30, where enhanced compost maturity and nutrient accumulation are observed. The findings indicate that optimal initial C/N ratios vary by agricultural residue type. A C/N ratio of 20 to 30 facilitates controlling the composting duration within 45 days, while a C/N ratio of 30 to 35 necessitates extending the duration beyond 45 days. The study highlights the effectiveness of adjusting the C/N ratio and applying microbial inoculants and physical amendments to optimize composting outcomes and control the composting duration.

The incorporation of rural landscape plants plays a pivotal role in the development and establishment of ecotourism. By studying the genetic diversity of plants in rural landscapes, the richness of genetic variation and the stability of the genetic structure within a population can be revealed. This serves as an important theoretical foundation for the construction of rural ecological landscapes and biodiversity maintenance and is of great significance for the construction of beautiful villages. In this study, eight native landscape species were selected from two ecotourism villages (Changkou Village, Sanming City, Fujian Province; and Paifang Community, Nanjing City, Jiangsu Province). Native rural landscape plant samples were collected from the whole village area. Phenotypic characteristics were measured, and ISSR-PCR experiments were performed. Through analysis of phenotypic features and detection of molecular markers, the Shannon index and Nei’s genetic diversity indexes were calculated to elucidate the levels of genetic diversity of native landscape plant species in different areas. Cluster analysis using phenotypic features identified five types of Liquidambar formosana, six types of Cyclobalanopsis chungii, four types of Quercus glauca, sixteen types of Zelkova serrata, seven types of Toona sinensis, ten types of Aster indicus, five types of Chrysanthemum indicum, and six types of Rubus hirsutus. The phenotypic coefficient variation and Shannon index of the eight native landscape plant species ranged from 0.23 to 0.58, and from 1.51 to 6.74, respectively. In the total area, artificial area and natural area, the Nei’s genetic diversity indexes of the eight native landscape plant species ranged from 0.240 to 0.536, 0.244 to 0.540, and 0.193 to 0.367, respectively. For the eight native landscape plant species, the percentage of polymorphic loci varied from 45.00% to 100.00%, the number of alleles varied from 1.45 to 2.00, and the number of effective alleles varied from 1.30 to 1.64. The results revealed that the phenotypic (Shannon index) and molecular (Nei’s genetic diversity index) genetic diversity levels of the eight native landscape plant species were higher than the average diversity level in numerous other landscape plant species. Additionally, the rural landscape plant species exhibited abundant genetic variation. The genetic diversity of certain rural landscape plant species exhibited a notable degree of variability; however, there were significant differences in the levels of genetic diversity observed between natural and artificial areas. In the context of rural landscape construction, it is important to prioritize the assessment of genetic diversity in rural landscape plant populations. Appropriate measures should be implemented to enhance the even distribution of genetic polymorphisms within the population and preserve the genetic diversity of native landscape plant species. This approach is essential to ensure the long-term stability of rural ecological landscapes.

Understanding genetic diversity and population structure is essential for the conservation and utilization of germplasm. Ginkgo biloba L. is a medicinal, edible and ornamental tree species. Detailed knowledge of genetic variability and diversity in different Ginkgo germplasm resources is still scarce. In this study, a total of 173,160 Expressed Sequence Tag Simple Sequences Repeat (EST-SSR) loci were derived from 43,073 Unigenes of the Ginkgo genome. A total of 43,731 pairs of specific primers were designed for the EST-SSR loci, with sequence lengths >20 bp, and 100 of the SSR primers were randomly selected. Among these, 20 EST-SSR markers were verified and used to assess the genetic diversity of 101 Ginkgo individuals collected from different regions. The average values for Shannon’s diversity index (I, 0.993), expected heterozygosity (0.566) and Nei’s genetic diversity index (H, 0.563) indicate a high level of genetic diversity of Ginkgo populations. Based on the EST-SSR markers, a core collection of Ginkgo germplasm comprising 27 genetic resources was constructed. The retention rates of the number of resources, the number of alleles, the number of effective alleles, the I index, the H index and the percentage of polymorphic loci of the constructed core collection are 26.73%, 95.29%, 103.43%, 102.25%, 102.91% and 100.00%, respectively. The molecular markers developed in this study are an effective tool for Ginkgo genetic diversity analysis and will facilitate the future breeding of this species.

The objective of the present study was to assess the effects of replacing corn silage with Phragmites australis shoot remainder (PSR) silage on intake, growth performance, serum biochemical parameters, and rumen microbial diversity of growing-finishing beef. Fifteen Angus beef cattle with an average body weight of 253 ± 2.94 kg were randomly divided into three groups (five replicas vs. each group vs. Angus beef cattle). The three treatments were group A fed 60% PSR silage + 40% concentrate, group B fed 30% PSR silage + 30% corn silage + 40% concentrate, and group C fed 60% corn silage + 40% concentrate. The adaptation period was 15 days, and the trial period lasted for 45 days. Results showed that the ADG was significantly higher, and FCR was significantly lower both in groups A and B compared with group C. The results of serum biochemical parameters showed that the concentration of GLU was significantly lower in group B than both groups A and C. Microbial diversity results showed that the OTUs, Shannon, Chao1, and ACE indices were significantly lower in group A compared with groups B and C. At the phyla level, the relative abundances of Tenericutes and Melainabacteria had significant differences among the three groups, and the relative abundances of Papillibacter, Anaeroplasma, and Anaerovorax had significant differences among the three groups at the genus level. Additionally, Rikenellaceae was the unique biomarker among the three groups. Furthermore, the results of function prediction showed that the gene families associated with metabolism of cofactors and vitamins, cellular processes and signaling, metabolism, biosynthesis of other secondary metabolites, infectious diseases, signaling molecules and interaction, nervous system, and digestive system were significantly decreased, while lipid metabolism was dramatically increased from groups A to C at KEGG level 2. At KEGG level 3, 11 metabolic pathways were significantly influenced among the three groups. In summary, these findings indicated that PSR silage substituted the corn silage totally or partially improved the growth performance, and altered the rumen microbial composition and diversity and the corresponding change in prediction function of rumen bacteria in Angus beef cattle.

[目的]筛选适宜的银杏树形,为银杏优质、丰产栽培提供参考.[方法]2019年4—9月,以开心形和主干分层形2种树形的银杏植株为研究对象,使用Yaxin-1102G光合仪测定2种树形银杏的光合作用相关参数,采用95％乙醇浸提法测定叶片叶绿素含量,分别采用蒽酮比色法、考马斯亮蓝法和索氏提取法测定银杏种仁的可溶性糖、淀粉、蛋白质和油脂含量,对2种树形植株的光合特性、种仁品质及种实产量进行比较分析.[结果]在2019年6月4日06:00—18:00和2019年4—9月各月份,总体上开心形银杏植株的净光合速率、蒸腾速率、气孔导度、胞间CO2浓度均大于主干分层形植株.2种树形银杏植株叶片的叶绿素a、叶绿素b含量均呈先升高、后降低的变化趋势,开心形银杏植株的叶绿素含量高于主干分层形植株.开心形银杏植株种仁的可溶性糖、油脂、淀粉、可溶性蛋白等内含物含量均高于主干分层形植株,但开心形银杏植株的种实产量低于主干分层形植株.[结论]开心形银杏树形结构较为合理,具有叶片叶绿素含量高、光合特性好、种仁品质优、种实产量稍低的特点,可通过适当修剪,培养结果枝,达到增产的目的;主干分层形植株的主枝多,叶片叶绿素含量低,光合特性差,种仁品质差,种实产量较高,可通过疏除过密枝条、加强肥水管理,促进优质银杏种实生产.

AGAMOUS (AG), a member of MADS-box gene family, is a key gene related to regulation of flower development in plants. The AG homologous gene GBM5 (Accession No.: AY114304.1) was obtained from the transcriptome of Ginkgo biloba . Primers were designed according to the obtained GBM5 gene sequence, and the full-length cDNA sequence of GBM5 gene with 732 bp in size and 243 amino acids in coding product can be synthetized by designing primers. The comparative analysis of evolutionary tree and amino acid sequence showed that ginkgo GBM5 was closely related to cycads AG and black spruce AG . qPCR analysis showed that the expression of GBM5 in different tissues of Ginkgo biloba was different at different periods, the expression levels of different tissues are as follows: Female flower>Male flower>Primordia>Foliage; Its expression is high in the undifferentiated stage of flower bud, the expression patterns were: April leaf>May leaf>September leaf, April primordia>May primordia>September primordia.

AGAMOUS(AG)属于MADS-box基因家族成员,是与花发育调控相关的关键基因.从银杏转录组中得到AG类同源基因GBM5(登录号:AY114304.1),根据GBM5基因序列设计引物,克隆获得GBM5基因的全长cDNA序列,其大小为732 bp,编码产物含243个氨基酸.进化树及氨基酸序列比对分析表明银杏GBM5与苏铁AG、黑云杉AG亲缘关系较近.qPCR分析显示,GBM5在银杏不同组织和不同时期的表达量均有差异,不同组表达量为:雌花＞雄花＞茎端＞叶;其在不同时期叶片和茎端表达量均为:4月＞5月＞9月.

Ginkgo biloba is a dioecious plant with a long juvenile stage. With advances in molecular technology, expression verification and functional analysis of some MADS-box family genes have been performed to explore the flowering mechanism in Ginkgo. Here, we selected the gene Gb01884 of different expression from transcriptome sequencing database, and isolated it from the shoot apical meristem (STM) of Ginkgo biloba. Full-length cDNA was cloned and sequence alignment was performed by NCBI platform. The result showed that Gb01884 was designated as an allele gene and named as GbMADS6, a SOC1 homolog gene. Using RT-qPCR to explore the GbMADS6 expression in spatial dynamic, we found that its expression level was high in leaves, apex stems, short shoots of both male and female Ginkgo trees. Then, the expression level of GbMADS6 was measured at the different development stages of leaves and apex stems. In apex stems, the expression level of GbMADS6 increased at initial differentiation stage of flower bud, and decreased gradually along with flower bud development. In leaves, the expression level of GbMADS6 decreased at initial differentiation stage of flower bud, while increased at exuberant stage of flower bud differentiation. This study provides the basis for further understanding the regulation mechanism of flowering in Ginkgo.

In this paper, the key genes of flowering regulation among three age stages was screened and the molecular mechanism of the flowering pathway was revealed in Ginkgo biloba . It can provide scientific basis for promoting early flowering, molecular breeding and spreading planting of Ginkgo biloba . High throughput sequencing technology and bioinformatics tools were used to sequence the transcriptome of male flower buds of Ginkgo biloba in three age stages. By analyzed the sequencing data, we screened out the key differential expression genes of age pathway. A total of 57.45 Gb of raw data was generated by transcriptome sequencing. The total number of Unigenes was 35 058 and annotated in the 8 functional databases (GO, COG, KEGG, KOG, NR, Pfam, Swiss-Prot, and eggNOG). The Unigenes were classified into 55 GO categories and 126 metabolic pathways. Analysis of differentially expressed genes revealed that 37 genes were up-regulated and 75 genes were down-regulated during the flower bud undifferentiated stage vs. initial stage of flower bud differentiation. A total of 592 genes were up-regulated and 871 genes were down-regulated during the initial stage of flower bud differentiation vs. flower bud differentiation stage. The flower bud undifferentiated stage vs. flower bud differentiation stage，961 genes were up-regulated and 1 203 genes were down-regulated. A large number of flowering related genes were discovered and finally screened out 11 key genes of flowering regulation in age pathway. including SPL (gene.Gb_23724, gene.Gb_03922), AP2 (gene.Gb_00766), MADS-box (gene.Gb_01886, gene.Gb_15398, gene.Gb_28337, Gingko_newGene_2213), Gibberellin-regulated protein(gene.Gb_34467, gene.Gb_28606, gene.Gb_33214)and DELLAs protein(gene.Gb_34644).