Pathogenic bacteria are the primary causative agents of economic losses in the aquaculture industry, and biological control is currently regarded as a promising strategy for prevention and management. Algae, as crucial components of marine ecosystems, host diverse and abundant microbial communities within their phycospheres. In order to explore the diversity and potential application value of algae-associated symbiotic or epiphytic actinomycetes resources in South China Sea, the isolation identification and antibacterial activity screening of symbiotic or epiphytic actinomycetes from Caulerpa sertularoides f. Longipes, collected from Lingshui, Hainan, were carried out. Actinomycetes were isolated through dilution coating method and identified according to the 16S rRNA gene sequences alignment and by phylogenetic tree construction. The results revealed that 20 strains were identified as Streptomyces, one as Nocardiopsis, and one as Microbacterium. The antibacterial activity of the fermented crude extracts of the obtained strains was evaluated against nine pathogenic bacteria, including Vibrio owensii using the filter paper method. Results showed that all strains exhibited inhibitory effects on at least one type of bacteria. High-performance liquid chromatography (HPLC) was employed to assess the chemical diversity of the crude extracts. Results showed that strain HZ057 had a higher abundance of secondary metabolites than other strains. To further investigate the salt stress tolerance of the strains, salt tolerance tests were conducted. The results showed that all the strains could grow well on 0%-4% NaCl, HZ054 and HZ057 could still grow at a salt concentration of 12%. The whole genome of HZ057 was sequenced and the functions of each gene cluster were predicted using antiSMASH. The analysis revealed that the genome contained 29 secondary metabolite genes clusters with diverse structural types, indicating that this strain is associated with a rich diversity of secondary metabolites. In this study, strains of Streptomyces, Nocardiopsis and Micrococcus were isolated firstly from the algae Caulerpa sertularoides f. Longipes in the South China Sea, indicating that the algae contained abundant actinomycete resources. Moreover, it was found that the identified strains exhibited significant antibacterial activity and the ability to produce a variety of secondary metabolites, suggesting the potentials for future research and applications.

Genetic engineering technology serves as an effective method to shorten crop breeding cycles, specifically cultivate new crop varieties, and identify plant gene functions. Induced promoters are important tools in genetic engineering research, among which thermally inducible promoters being extensively utilized in plant molecular biology owing to the simple vector structure, convenient induction, and low cost. At present, the development of genetic engineering technology in rubber trees lags behind. Functional studies of target genes typically use constitutive promoters, which limits the progress of related work. In this study, rubber tree calli were treated by heat. Through transcriptome sequencing analysis, identified eight genes that were non-expressed or minimally expressed, but exhibited high level expression after heat induction in calli. After heat induced expression changes and specificity evaluation, two candidate genes HbHSP17.6C and HbHSP17.6B that specifically respond to heat treatment were identified. Further through nested PCR, we cloned the 1962 nt sequence upstream of the start codon of the heat shock protein gene HbHSP17.6C. Confirm that it is composed of a core transcription region and multiple cis acting elements, and is named pHbHSP17.6C. It is inferred that this promoter could be used for gene function research in rubber trees and other closely related plants, which is expected to provide new tool options for related research.

Banana is a typical respiration fruit. MaERF15 is a transcription factor located in the nucleus and has the effect of regulating postharvest ripening of banana fruits. MaACO8 is a key ethylene biosynthesis-ACC oxidase gene expressed at high levels during postharvest ripening of banana fruits. But the molecular interaction mechanism between the two has not been clarified. To explore the transcriptional regulation mechanism of ethylene response factor MaERF15 on the key genes of downstream ethylene synthesis was to provide a theoretical basis for the innovation of postharvest preservation technology of banana fruits. In this study, the promoter sequence of MaACO8 was isolated from banana DNA, and the promoter activity of MaACO8 was studied by bioinformatics analysis and GUS staining. Yeast monohybridization, EMSA, dual fluorescein reporter system and in vivo imaging system were used to study the interaction mechanism between MaERF15 and MaACO8 promoter. The results showed that there were 11 GCC-boxes in the promoter sequence of MaACO8 that bind to AP2/ERF transcription factors, which had strong priming activity. MaERF15 could specifically bind to the GCC-box of the MaACO8 promoter, activate the expression of MaACO8, promote the biosynthesis of ethylene, and regulate fruit ripening. The results further improved the theory of postharvest ethylene biosynthesis regulating fruit ripening of banana fruits, and would provide genetic resources and theoretical basis for the research and development of new technologies for storage and transportation tolerance breeding and maturity regulation of bananas, respectively.

Taking the chloroplast genomes of five coffea plants, namely Coffea liberica, C. canephora, C. arabica, C. eugenioides, and C. racemosa, as the research objects, a series of statistical and comparative analyses were carried out. The results demonstrated that the lengths of the chloroplast genomes varied from 154 751 bp to 155 189 bp, with C. arabica a possessing the longest genome and C. canephora having the shortest. The average GC content was determined to be 34.98%. Both C. liberica and C. arabica encoded 130 genes, while C. eugenioides had the largest number of genes, totaling 138, and C. racemosa had the least, with only 121. Upon comparing the border regions of the chloroplast genomes of the five coffee plants, it was observed that the directional sequence arrangements were consistent, thereby reflecting the high conservation of the chloroplast genome structure. The analysis of SSR sequences indicated that the five coffee plants exhibited a pronounced AT bias, and the types and quantities of SSRs differed among them. Through the analysis of nucleotide diversity variation sites, five segments with relatively significant nucleotide variations were identified, namely PetN-PsbM, accD, accD-PsaI, rpl16 and ndhF-rpl32. Furthermore, based on the combined analysis of the chloroplast genomes and the five highly variable nucleotide regions, a phylogenetic tree of 19 Coffea plants was successfully constructed, which shed light on their genetic relationships. This study can serve as a valuable reference for the identification of germplasm resources, the exploration of origin and evolution, as well as the hybrid breeding of Coffea plants.

The diversity of orchid labellum, a specialized petal, has great ornamental and biological value, but the formation mechanism has not been solved so far. APETALA3-3 (AP3-3) is a floral organ identity gene, which is related to the formation of orchid labellum, but there is no report on how it regulating the formation mechanism of orchid labellum diversity. In this project, wild type and DoAP3-3 overexpressing floral organs of Dendrobium officinale were used as the research objects to explore the formation mechanism from the perspective of transcription factor DoAP3-3 regulating downstream target genes through DAP-seq and RNA-seq joint analysis. The results showed that a total of 7 key candidate target genes, MADS6, NAC029, NAC054, WOX3, AS2, ERECTA, AG were identified, which may regulate floral organ development and floral morphogenesis development under the action of DoAP3-3 by specific regulation or interaction with other genes. The interaction between transcription factor DoAP3-3 and MADS6 was verified by yeast one-hybrid experiment, which further affecting floral morphogenesis development. This study would lay a foundation for preliminary analysis of the regulatory mechanism between DoAP3-3 and its target genes, and exploring the formation mechanism of highly specialized and diversified flower morphology in Orchidaceae.

Sucrose phosphate synthase (SPS) plays a crucial role in the sucrose synthesis process, and investigating the biological functions of the SPS family in durian (Durio zibethinus Murr.) can contribute to enhancing fruit quality. In the durian genome, 10 SPS members were identified and designated as DzSPS1 to DzSPS10. The results indicated that the average hydrophobicity coefficient was less than 0, with isoelectric points ranging from 5.70 to 6.68, suggesting that they are hydrophilic acidic proteins. Subcellular localization predictions primarily placed them on the cell membrane and nucleus. Analysis of conserved motifs within the gene family revealed variations in the number and distribution of motifs among durian SPS members, although all contained motif 3, indicating that motif 3 is a significant conserved domain within the durian SPS gene family. Gene structure analysis showed that durian SPS genes were structurally similar, containing 8 to 15 exons and 7 to 13 introns. Phylogenetic tree analysis demonstrated that durian SPS genes could be divided into two subfamilies, with subfamily Ⅱ comprising nine members and subfamily Ⅰ containing one member. Compared to SPS genes in horticultural fruit trees such as cacao and citrus, durian SPS genes exhibited closer phylogenetic relationships with Arabidopsis and rice SPS genes. Seven members of the durian SPS family shared high spatial structural similarity, with secondary structures predominantly consisting of α-helices and random coils. Cis-acting element analysis suggested that durian SPS genes may be readily induced by response elements related to light, low temperature, drought, and gibberellin. This study detected that the primary soluble sugars in durian fruit are sucrose, fructose, and glucose, with sucrose content significantly higher than that of fructose and glucose, and notable differences observed among different varieties. Fluorescence quantitative analysis revealed significant variations in SPS expression levels among different durian varieties, with the expression patterns of DzSPS3 and DzSPS7 correlating with changes in total sugar content between varieties, suggesting that DzSPS3 and DzSPS7 may be key members involved in sugar accumulation. By analyzing the structure and physicochemical properties of durian SPS genes and exploring the SPS accumulation characteristics in different varieties, this study would provide a reference for further investigation into the biological functions of the SPS family in durian.

The fruit of Aquilaria sinensis contains a class of tetracyclic triterpenoids known as cucurbitacins, which exhibit anti-inflammatory, hepatoprotective, and antitumor activities. Cytochrome P450s (CYP) are key enzymes in the biosynthesis pathway of cucurbitacins. The P450 genes for cucurbitacin synthesis in A. sinensis have not been extensively studied. In this study, a P450 gene (AsCYP131) was cloned based on A. sinensis transcriptome data. The complete open reading frame (ORF) of AsCYP131 gene was 1491 bp, encoding a protein of 496 amino acids with a molecular weight of 55.39 kDa. The theoretical isoelectric point (pI) of the protein was 7.65, with an average hydrophilicity coefficient of –0.053, and an instability index of 47.16, classifying it as an unstable protein. The protein contained 40 potential phosphorylation sites, and its secondary structure was predominantly composed of α-helix and random coil. The results of multiple sequence alignment and phylogenetic tree analysis showed that the protein encoded by the AsCYP131 gene clustered into a single unit with CsCYP, CmCYP, and ClCYP, which have been reported to be involved in the biosynthesis of cucurbitacins. The sequence of the functional structural domains at the C-terminal showed high consistency. At the same time, the expression levels of AsCYP131 in different tissues of A. sinensis detected by real-time fluorescence quantitative PCR (RT-qPCR). The results indicated differential expression levels of AsCYP131 across various tissues, including roots, stems, leaves, flowers, fruits, and seeds, with the highest relative expression observed in fruits. This study would serve as a valuable reference for the subsequent validation of the functional role of the AsCYP131 gene in cucurbitacin biosynthesis.

Fici Hirtae Radix, a Chinese herbal medicine, is prepared from the dry roots of Ficus hirta Vahl. This study aimed to provide theoretical and empirical support for the genetic diversity analysis, genetic map construction, and assisted breeding of F. hirta Vahl. by developing SSR molecular markers. Four typical leaves of F. hirta Vahl. were selected as the samples, and site feature analysis and molecular marker development were performed after transcriptome sequencing. A total of 16 851 SSR loci were identified from 34 375 transcriptome unigene sequences, distributed across 12 094 unigene sequences, resulting in a distribution frequency of 35.18%. The average frequency was one SSR locus every 2638 bp, with a density of 3.68 kb. Five distinct nucleotide motifs were observed, with the motif repeating six times being the most prevalent, constituting 20.92% of all SSRs, and typically less than 29 bp in length. Di-nucleotide repeats were predominant, followed by tri-and tetra-nucleotide repeats. (AG/CT)n was the most abundant repeat motif, representing 26.05% of all SSRs, while (AT/AT)n was the second most common, accounting for 18.69%. 100 EST-SSR primers were randomly selected to amplify target product using genomic DNA from four different leaf types of F. hirta Vahl. 89 primers exhibited polymorphism across the germplasms. Nine primer pairs, distinguished by the high definition and clarity, were selected to perform DNA amplification and construct DNA fingerprints for 31 specimens sourced from different regions. The average percentage of polymorphic bands observed across these primers was 72.04%. The substantial degree of polymorphism facilitated the unambiguous identification of each of the 31 germplasm samples, and robust DNA fingerprint profiles were successfully established for each specimen. This study demonstrated that SSR loci within the transcriptome of F. hirta Vahl. were rich in information and highly utilizable, offering valuable data support for future research endeavors.

In order to explore the characteristics and molecular regulation mechanism of high temperature albinism of tea variety Yaoqiu (YQ) and its molecular regulation mechanism, the effects of low temperature albinism on the shoot with one bud and two leaves of tea variety YQ in spring (YQC), summer (YQX), autumn albinism (YQQ) and autumn green (YQQL), and Baiye No. 1 (BY1H) in spring albinism (BY1HC), their biochemical components, and transcriptome sequencing were carried out on the new shoots in summer (BY1HX) and autumn (BY1HQ). The results of biochemical analysis showed that the total free amino acid content and tea polyphenols content of YQQ albino fresh leaves were lower than those of YQC green fresh leaves, and the difference of total free amino acid content was significant; while the total free amino acid content of BY1HC albino fresh leaves was significantly higher than that of BY1HQ green fresh leaves, and the tea polyphenols content was significantly lower than that of BY1HQ green fresh leaves. Cluster analysis revealed that the gene expression profiles of YQQ albino fresh leaves formed a distinct cluster. The comparison between YQQ and BY1HQ exhibited the highest number of differentially expressed genes. The new shoot leaves of YQ showed an albino phenotype induced by high-temperature stress in late summer and early autumn. This stress affected the structure of microtubules, cells, and subcellular components, leading to a reduction in the contents of amino acids and polyphenols. The three functional categories exhibiting the most significant gene enrichment were microtubule binding, movement of cellular or subcellular components, and non-membrane-bound organelles. Similarly, the top three pathways with the highest significance in gene enrichment were the flavonoid biosynthesis pathway, the starch and sucrose metabolism pathway, and the amino sugar and nucleotide sugar metabolism pathway. Through gene co-expression network analysis, modules exhibiting high expression levels were identified. Subsequently, the ten genes demonstrating the highest total connectivity (K value) were selected for further analysis and annotation. Notably, the functions of genes TGY042732 and the novel gene designated as novel.276 could not be predicted. These findings would provide a theoretical foundation for understanding the phenomenon of albinism in tea resources under conditions of elevated temperature.

The technology of secondary somatic embryo cyclic multiplication has realized the large-scale propagation of somatic embryo plantlets (self-rooted juvenile clones) of Hevea brasiliensis. This technology needs to cut the cotyledon embryo into 2 mm×2 mm pieces. A large amount of ethylene and reactive oxygen species (ROS) will be produced at the wound site, and much ethylene and ROS will also formed during culture process. Ethylene and ROS have adverse effects on somatic embryogenesis of H. brasiliensis. Silver nitrate (AgNO₃) is an ethylene inhibitor and also affects enzyme activity. In this paper, the effects of different AgNO₃ concentrations (0, 2.5, 5.0, 10.0, 15.0 mg/L) and different time (7, 14, 21, 28 days) on the embryo block browning and secondary somatic embryogenesis of H. brasiliensis were studied, and the phenotype and ploidy of regenerated plantlets were evaluated. AgNO₃ significantly reduced the browning of embryo blocks and the production of ROS. The effect of 5-15 mg/L was better than that of 2.5 mg/L, and the effect of 21 days treatment was better than that of the other three treatments. 2.5-15.0 mg/L AgNO₃ treated 7-28 days did not significantly increase the number of embryonic blocks, but the number of cotyledon embryos in 5.0 mg/L AgNO₃ treated for 21 and 28 days, 10.0 mg/L AgNO₃ treated for 21 days, and 15.0 mg/L AgNO₃ treated for 7-21 days were significantly higher than those in the control. The number of embryonic blocks was negatively correlated with browning, but not significantly, the number of cotyledon embryos was significantly negatively correlated with browning. The phenotype of regenerated plantlets from AgNO₃ treatments had no obvious difference compared with the control, and the chromosome ploidy was the same as the control. The results would provide technical support for improving the efficiency of secondary somatic embryogenesis in H. brasiliensis.