Analysis of differential mRNA and miRNA expression induced by heterogeneous grafting in Gleditsia sinensis.

Gleditsia sinensis Lam. is a multifaceted plant with medicinal, edible, chemical, timber, and ornamental applications. However, the effect of rootstocks on scions after grafting is still unclear. This study examined the mRNA and miRNA transcriptome among homografts, heterografts, and seedlings. GO enrichment analysis between seedlings and homograft/heterograft combinations revealed that biosynthesis, degradation, and transport were enriched. The KEGG enrichment results showed that plant hormone signal transduction and the plant MAPK signaling pathway were enriched in both seedlings and heterograft combinations. Through weighted correlation network analysis (WGCNA), the hub genes related to the content of plant hormones were obtained. Taking G. sinensis as the scion, there were 4594, 2887, 3429, and 5959 mRNAs that were specifically expressed in the grafted plants of G. sinensis/G. fera, G. sinensis/G. delavayi, G. sinensis/G. microphylla, and G. sinensis/G. japonica, respectively. The specifically expressed mRNA genes may participate in such processes and pathways as the rhythmic process, circadian rhythm, gibberellic-acid-mediated signaling pathway, and peptide-based amino acid modification. Additionally, 3, 16, 2, and 15 specifically expressed miRNAs were identified. This study examines the impact of grafting on gene expression in Gleditsia plants and establishes a foundation for the development of new resources and rootstock breeding.

Metabolite components and nutritional composition of the endosperm in seven species from Gleditsia.

As an important agricultural product, the endosperm portion of Gleditsia sinensis seeds, called "zào jiǎo mǐ" (ZJM) in Chinese, has gradually gained popularity and has been accepted by the public. However, there is limited information on the nutritional value and metabolic components of endosperm among Gleditsia. This study compared the endosperm composition among seven species. The types of metabolites, content of nutrients and amino acids were determined. A total of 4495 types of metabolites were detected. Galactose metabolism (gmx00052) was enriched in all combinations compared with G. sinensis. The polysaccharides content ranged from 51.49 to 80.37 g/100 g. Based on considerations of growth rate, seed yield, amino acid content, and interspecific differences, G. fera could be an alternative planting option to G. sinensis. These results can provide a reference for growers in selecting Gleditsia varieties and provide insights into the industrial applications of Gleditsia endosperm products.

Tradeoffs among root functional traits for phosphorus acquisition in 13 soybean genotypes contrasting in mycorrhizal colonization.

BACKGROUND AND AIMS: Plants have adapted to acquire phosphorus (P) primarily through advantageous root morphologies, responsive physiological pathways, and associations with mycorrhizal fungi. Yet, to date, little information exists on how variation in arbuscular mycorrhizal (AM) colonization is coordinated with root morphological and physiological traits to enhance P acquisition. METHODS: Thirteen root functional traits associated with P acquisition were characterized at full bloom stage in pot cultures under low soil P availability conditions for 13 soybean genotypes contrasting in AM colonization. KEY RESULTS: Significant variation in root functional traits was observed in response to low P stress among the 13 tested soybean genotypes contrasting in AM colonization. Genotypes with low AM colonization exhibited greater root proliferation but with less advantageous root physiological characteristics for P acquisition. In contrast, genotypes with high AM colonization exhibited less root growth but higher phosphatase activities and carboxylate content in the rhizosheath. Root dry weights, and contents of carbon and P were positively correlated with root morphological traits of different root orders and whole root systems, and were negatively correlated with AM colonization of fine roots and whole root systems, as well as, rhizosheath phosphatase activities and carboxylate contents. These results taken in combination with significant positive correlation between plant P content and root morphological traits indicate that root morphological traits play a primary role in soybean P acquisition. CONCLUSIONS: The results suggest that efficient P acquisition involves tradeoffs among carbon allocation to root proliferation, mycorrhizal symbiosis, or P-mobilizing exudation. Complementarity and complexity in the selection of P acquisition strategies was notable among soybean genotypes contrasting in AM colonization, which is closely related to plant C budgeting.

Changes and driving factors of microbial community composition and functional groups during the decomposition of Pinus massoniana deadwood.

Clarifying changes in the microbial community in deadwood at different stages of decomposition is crucial for comprehending the role of deadwood in the biogeochemical processes and the sustainability of forest development. However, there have been no reports on the dynamics of microbial community during the decomposition of Pinus massoniana. We used the "space-for-time" substitution to analyze the characteristics of microbial community changes and the key influencing factors in the P. massoniana deadwood during different decomposition stages by 16S and ITS rRNA gene sequencing. The results suggest that the microbial community structure of the early decomposition (decay class I) was significantly different from the other decay classes, while the diversity and richness of the microbial community were the highest in the late decomposition (decay class V). The Linear Discriminant Analysis Effect Size analysis revealed that most bacterial and fungal taxa were significantly enriched in decay classes I and V deadwood. During the initial stages of decomposition, the relative abundance of the bacterial functional group responsible for carbohydrate metabolism was greater than the later stages. As decomposition progressed, the relative abundance of saprophytic fungi gradually decreased, and there was a shift in the comparative abundance of mixed saprophytic-symbiotic fungi from low to high before eventually decreasing. Total organic carbon, total nitrogen, carbon-to-nitrogen ratio, total potassium, total phenol, condensed tannin, lignin, and cellulose were significantly correlated with microbial community structure, with the carbon-to-nitrogen ratio having the greatest effect. Our results indicate that the physicochemical properties of deadwood, microbial community structural composition and functional group changes were related to the decay class, among which the carbon-to-nitrogen ratio may be an important factor affecting the composition and diversity of microbial communities.

Evolution of H7N9 highly pathogenic avian influenza virus in the context of vaccination.

Human infections with the H7N9 influenza virus have been eliminated in China through vaccination of poultry; however, the H7N9 virus has not yet been eradicated from poultry. Carefully analysis of H7N9 viruses in poultry that have sub-optimal immunity may provide a unique opportunity to witness the evolution of highly pathogenic avian influenza virus in the context of vaccination. Between January 2020 and June 2023, we isolated 16 H7N9 viruses from samples we collected during surveillance and samples that were sent to us for disease diagnosis. Genetic analysis indicated that these viruses belonged to a single genotype previously detected in poultry. Antigenic analysis indicated that 12 of the 16 viruses were antigenically close to the H7-Re4 vaccine virus that has been used since January 2022, and the other four viruses showed reduced reactivity with the vaccine. Animal studies indicated that all 16 viruses were nonlethal in mice, and four of six viruses showed reduced virulence in chickens upon intranasally inoculation. Importantly, the H7N9 viruses detected in this study exclusively bound to the avian-type receptors, having lost the capacity to bind to human-type receptors. Our study shows that vaccination slows the evolution of H7N9 virus by preventing its reassortment with other viruses and eliminates a harmful characteristic of H7N9 virus, namely its ability to bind to human-type receptors.

Identification of novel mammalian viruses in tree shrews ( Tupaia belangeri chinensis).

The Chinese tree shrew ( Tupaia belangeri chinensis), a member of the mammalian order Scandentia, exhibits considerable similarities with primates, including humans, in aspects of its nervous, immune, and metabolic systems. These similarities have established the tree shrew as a promising experimental model for biomedical research on cancer, infectious diseases, metabolic disorders, and mental health conditions. Herein, we used meta-transcriptomic sequencing to analyze plasma, as well as oral and anal swab samples, from 105 healthy asymptomatic tree shrews to identify the presence of potential zoonotic viruses. In total, eight mammalian viruses with complete genomes were identified, belonging to six viral families, including Flaviviridae, Hepeviridae, Parvovirinae, Picornaviridae, Sedoreoviridae, and Spinareoviridae. Notably, the presence of rotavirus was recorded in tree shrews for the first time. Three viruses - hepacivirus 1, parvovirus, and picornavirus - exhibited low genetic similarity (<70%) with previously reported viruses at the whole-genome scale, indicating novelty. Conversely, three other viruses - hepacivirus 2, hepatovirus A and hepevirus - exhibited high similarity (>94%) to known viral strains. Phylogenetic analyses also revealed that the rotavirus and mammalian orthoreovirus identified in this study may be novel reassortants. These findings provide insights into the diverse viral spectrum present in captive Chinese tree shrews, highlighting the necessity for further research into their potential for cross-species transmission.

Physiological responses to drought stress of three pine species and comparative transcriptome analysis of Pinus yunnanensis var. pygmaea.

Drought stress can significantly affect plant growth, development, and yield. Fewer comparative studies have been conducted between different species of pines, particularly involving Pinus yunnanensis var. pygmaea (P. pygmaea). In this study, the physiological indices, photosynthetic pigment and related antioxidant enzyme changes in needles from P. pygmaea, P. elliottii and P. massoniana under drought at 0, 7, 14, 21, 28 and 35 d, as well as 7 days after rehydration, were measured. The PacBio single-molecule real-time (SMRT) and Illumina RNA sequencing were used to uncover the gene expression differences in P. pygmaea under drought and rehydration conditions. The results showed that the total antioxidant capacity (TAOC) of P. pygmaea was significantly higher than P. massoniana and P. elliottii. TAOC showed a continuous increase trend across all species. Soluble sugar (SS), starch content and non-structural carbohydrate (NSC) of all three pines displayed a "W" pattern, declining initially, increasing, and then decreasing again. P. pygmaea exhibits stronger drought tolerance and greater recovery ability under prolonged drought conditions. Through the PacBio SMRT-seq, a total of 50,979 high-quality transcripts were generated, and 6,521 SSR and 5,561 long non-coding RNAs (LncRNAs) were identified. A total of 2310, 1849, 5271, 5947, 7710, and 6854 differentially expressed genes (DEGs) were identified compared to the control (Pp0D) in six pair-wise comparisons of treatment versus control. bHLH, NAC, ERF, MYB_related, C3H transcription factors (TFs) play an important role in drought tolerance of P. pygmaea. KEGG enrichment analysis and Gene set enrichment analysis (GSEA) analysis showed that P. pygmaea may respond to drought by enhancing metabolic processes such as ABA signaling pathway, alpha-linolenic acid. Weighted gene co-expression network analysis (WGCNA) revealed GST, CAT, LEC14B, SEC23 were associated with antioxidant enzyme activity and TAOC. This study provides a basis for further research on drought tolerance differences among coniferous species.

Transcriptome analysis reveals regulatory mechanisms of different drought-tolerant Gleditsia sinensis seedlings under drought stress.

BACKGROUND: Gleditsia sinensis is a significant tree species from both ecological and economic perspectives. However, its growth is hampered by temporary droughts during the seedling stage, thereby impeding the development of the G. sinensis industry. Drought stress and rehydration of semi-annual potted seedlings using an artificial simulated water control method. RNA sequencing (RNA-seq) analyses were conducted on leaves collected from highly resistant (HR) and highly susceptible (HS) seedling families at five different stages during the process of drought stress and rehydration to investigate their gene expression patterns. RESULTS: The differentially expressed genes (DEGs) were predominantly enriched in pathways related to "chloroplast" (GO:0009507), "photosynthesis" (GO:0015979), "plant hormone signal transduction" (map04075), "flavonoid biosynthesis" (map00941), "stress response", "response to reactive oxygen species (ROS)" (GO:0000302), "signal transduction" (GO:0007165) in G. sinensis HR and HS families exposed to mild and severe drought stress. Additionally, the pathways related to "plant hormone signal transduction" (map04075), and osmoregulation were also enriched. The difference in drought tolerance between the two families of G. sinensis may be associated with "transmembrane transporter activity" (GO:0022857), "stress response", "hormones and signal transduction" (GO:0007165), "cutin, suberine and wax biosynthesis" (map00073), "ribosome" (map03010), "photosynthesis" (map00195), "sugar metabolism", and others. An enrichment analysis of DEGs under severe drought stress suggests that the drought tolerance of both families may be related to "water-soluble vitamin metabolic process" (GO:0006767), "photosynthesis" (map00195), "plant hormone signal transduction" (map04075), "starch and sucrose metabolism" (map00500), and "galactose metabolism" (map00052). Osmoregulation-related genes such as delta-1-pyrroline-5-carboxylate synthase (P5CS), Amino acid permease (AAP), Amino acid permease 2 (AAP2) and Trehalose-phosphate synthase (TPS), as well as the antioxidant enzyme L-ascorbate peroxidase 6 (APX6), may be significant genes involved in drought tolerance in G. sinensis. Five genes were selected randomly to validate the RNA-seq results using quantitative real-time PCR (RT-qPCR) and they indicated that the transcriptome data were reliable. CONCLUSIONS: The study presents information on the molecular regulation of the drought tolerance mechanism in G. sinensis and provides a reference for further research on the molecular mechanisms involved in drought tolerance breeding of G. sinensis.

N-Glycan Profiles of Neuraminidase from Avian Influenza Viruses.

The cleavage of sialic acids by neuraminidase (NA) facilitates the spread of influenza A virus (IV) descendants. Understanding the enzymatic activity of NA aids research into the transmission of IVs. An effective method for purifying NA was developed using p-aminophenyloxamic acid-modified functionalized hydroxylated magnetic particles (AAMPs), and from 0.299 to 0.401 mg of NA from eight IV strains was isolated by 1 mg AAMP. A combination of lectin microarrays and MALDI-TOF/TOF-MS was employed to investigate the N-glycans of isolated NAs. We found that more than 20 N-glycans were identified, and 16 glycan peaks were identical in the strains derived from chicken embryo cultivation. Multi-antennae, bisected, or core-fucosylated N-glycans are common in all the NAs. The terminal residues of N-glycans are predominantly composed of galactose and N-acetylglucosamine residues. Meanwhile, sialic acid residue was uncommon in these N-glycans. Further computational docking analysis predicted the interaction mechanism between NA and p-aminophenyloxamic acid.

Characterization of the chloroplast genome of Gleditsia species and comparative analysis.

The genus Gleditsia has significant medicinal and economic value, but information about the chloroplast genomic characteristics of Gleditsia species has been limited. Using the Illumina sequencing, we assembled and annotated the whole chloroplast genomes of seven Gleditsia species (Gleditsia sinensis, Gleditsia japonica var. delavayi (G. delavayi), G. fera, G. japonica, G. microphylla, Fructus Gleditsiae Abnormalis (Zhu Yá Zào), G. microphylla mutant). The assembled genomes revealed that Gleditsia species have a typical circular tetrad structure, with genome sizes ranging from 162,746 to 170,907 bp. Comparative genomic analysis showed that most (65.8-75.8%) of the abundant simple sequence repeats in Gleditsia and Gymnocladus species were located in the large single copy region. The Gleditsia chloroplast genome prefer T/A-ending codons and avoid C/G-ending codons, positive selection was acting on the rpoA, rpl20, atpB, ndhA and ycf4 genes, most of the chloroplast genes of Gleditsia species underwent purifying selection. Expansion and contraction of the inverted repeat (IR)/single copy (SC) region showed similar patterns within the Gleditsia genus. Polymorphism analysis revealed that coding regions were more conserved than non-coding regions, and the IR region was more conserved than the SC region. Mutational hotspots were mostly found in intergenic regions such as "rps16-trnQ", "trnT-trnL", "ndhG-ndhI", and "rpl32-trnL" in Gleditsia. Phylogenetic analysis showed that G. fera is most closely related to G. sinensis,G. japonica and G. delavayi are relatively closely related. Zhu Yá Zào can be considered a bud mutation of the G. sinensis. The albino phenotype of G. microphylla mutant is not caused by variations in the chloroplast genome, and that the occurrence of the albino phenotype may be due to mutations in chloroplast-related genes involved in splicing or localization functions. This study will help us enhance our exploration of the genetic evolution and geographical origins of the Gleditsia genus.

The soybean sugar transporter GmSWEET6 participates in sucrose transport towards fungi during arbuscular mycorrhizal symbiosis.

In arbuscular mycorrhizal (AM) symbiosis, sugars in root cortical cells could be exported as glucose or sucrose into peri-arbuscular space for use by AM fungi. However, no sugar transporter has been identified to be involved in sucrose export. An AM-inducible SWEET transporter, GmSWEET6, was functionally characterised in soybean, and its role in AM symbiosis was investigated via transgenic plants. The expression of GmSWEET6 was enhanced by inoculation with the cooperative fungal strain in both leaves and roots. Heterologous expression in a yeast mutant showed that GmSWEET6 mainly transported sucrose. Transgenic plants overexpressing GmSWEET6 increased sucrose concentration in root exudates. Overexpression or knockdown of GmSWEET6 decreased plant dry weight, P content, and sugar concentrations in non-mycorrhizal plants, which were partly recovered in mycorrhizal plants. Intriguingly, overexpression of GmSWEET6 increased root P content and decreased the percentage of degraded arbuscules, while knockdown of GmSWEET6 increased root sugar concentrations in RNAi2 plants and the percentage of degraded arbuscules in RNAi1 plants compared with wild-type plants when inoculated with AM fungi. These results in combination with subcellular localisation of GmSWEET6 to peri-arbuscular membranes strongly suggest that GmSWEET6 is required for AM symbiosis by mediating sucrose efflux towards fungi.

Full-length transcriptome characterization and comparative analysis of Gleditsia sinensis.

As an economically important tree, Gleditsia sinensis Lam. is widely planted. A lack of background genetic information on G. sinensis hinders molecular breeding. Based on PacBio single-molecule real-time (SMRT) sequencing and analysis of G. sinensis, a total of 95,183 non-redundant transcript sequences were obtained, of which 93,668 contained complete open reading frames (ORFs), 2,858 were long non-coding RNAs (LncRNAs) and 18,855 alternative splicing (AS) events were identified. Genes orthologous to different Gleditsia species pairs were identified, stress-related genes had been positively selected during the evolution. AGA, AGG, and CCA were identified as the universal optimal codon in the genus of Gleditsia. EIF5A was selected as a suitable fluorescent quantitative reference gene. 315 Cytochrome P450 monooxygenases (CYP450s) and 147 uridine diphosphate (UDP)-glycosyltransferases (UGTs) were recognized through the PacBio SMRT transcriptome. Randomized selection of GsIAA14 for cloning verified the reliability of the PacBio SMRT transcriptome assembly sequence. In conclusion, the research data lay the foundation for further analysis of the evolutionary mechanism and molecular breeding of Gleditsia.

Rapid detection of avian influenza virus based on CRISPR-Cas12a.

BACKGROUND: Avian influenza (AI) is a disease caused by the avian influenza virus (AIV). These viruses spread naturally among wild aquatic birds worldwide and infect domestic poultry, other birds, and other animal species. Currently, real-time reverse transcription polymerase chain reaction (rRT-PCR) is mainly used to detect the presence of pathogens and has good sensitivity and specificity. However, the diagnosis requires sophisticated instruments under laboratory conditions, which significantly limits point-of-care testing (POCT). Rapid, reliable, non-lab-equipment-reliant, sensitive, and specific diagnostic tests are urgently needed for rapid clinical detection and diagnosis. Our study aimed to develop a reverse transcription recombinase polymerase amplification (RT-RPA)/CRISPR method which improves on these limitations. METHODS: The Cas12a protein was purified by affinity chromatography with Ni-agarose resin and observed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Specific CRISPR RNA (crRNA) and primers targeting the M and NP genes of the AIV were designed and screened. By combining RT-RPA with the Cas12a/crRNA trans-cleavage system, a detection system that uses fluorescence readouts under blue light or lateral flow strips was established. Sensitivity assays were performed using a tenfold dilution series of plasmids and RNA of the M and NP genes as templates. The specificity of this method was determined using H1-H16 subtype AIVs and other avian pathogens, such as newcastle disease virus (NDV), infectious bursal disease virus (IBDV), and infectious bronchitis virus (IBV). RESULTS: The results showed that the method was able to detect AIV and that the detection limit can reach 6.7 copies/µL and 12 copies/µL for the M and NP gene, respectively. In addition, this assay showed no cross-reactivity with other avian-derived RNA viruses such as NDV, IBDV, and IBV. Moreover, the detection system presented 97.5% consistency and agreement with rRT-PCR and virus isolation for detecting samples from poultry. This portable and accurate method has great potential for AIV detection in the field. CONCLUSION: An RT-RPA/CRISPR method was developed for rapid, sensitive detection of AIV. The new system presents a good potential as an accurate, user-friendly, and inexpensive platform for point-of-care testing applications.

Comparative transcriptome analysis of dioecious floral development in Trachycarpus fortunei using Illumina and PacBio SMRT sequencing.

BACKGROUND: Trachycarpus fortunei is a plant with significant economic and ornamental value. Both male and female flowers of T. fortunei originate as bisexual flowers, and selective abortion occurs during floral development. However, the regulatory mechanisms underlying this process remain unclear in T. fortunei. In this study, transcriptome sequencing with Illumina and Pacific BioSciences (PacBio) single-molecule real-time (SMRT) platforms were used to investigate gene expression differences between male and female T. fortunei plants. RESULTS: A total of 833,137 full-length non-chimeric (FLNC) reads were obtained, and 726,846 high-quality full-length transcripts were identified. A total of 159 genes were differentially expressed between male and female flowers at all development stages. Some of the differentially expressed genes (DEGs) showed male bias, including serine/threonine-protein kinase (STPK), THUMP1 homolog and other genes. Through single-nucleotide polymorphisms(SNPs) identification, 28 genes were considered as potential sex-associated SNPs. Time-Ordered Gene Co-expression Network (TO-GCN) analysis revealed that MADS2 and MADS26 may play important roles in the development of female and male flowers T. fortune plants, respectively. CONCLUSIONS: These findings provide a genetic basis for flower development and differentiation in T. fortunei, and improve our understanding of the mechanisms underlying sexual differentiation in T. fortunei.

Physiological response and drought resistance evaluation of Gleditsia sinensis seedlings under drought-rehydration state.

G. sinensis is a crucial tree species in China, possessing important economic and ecological value, and having a wide geographical distribution. G. sinensis seedlings is highly vulnerable to the drought-rehydration-drought cycle during their growth, and there is a lack of quantitative and systematic research on the physiological mechanisms of drought resistance and rehydration in G. sinensis. There is also a lack of good drought-resistant families and reliable methods for evaluating drought resistance, which severely hinders the selection and promotion of drought-resistant G. sinensis families and the industry's development. Therefore, this study selection 58 families seedlings of G. sinensis to drought stress and rehydration using an artificial simulated water control method in potted seedlings. The aim was to compare the effects of different levels of drought and rehydration on the growth and physiological indices of seedlings from different families. Identification of drought-resistant families and dependable drought related indices and techniques, the explanation of divergence in drought stress effects on various drought-resistant seedlings and the mechanisms underpinning growth and physiological responses, and the provision of theoretical reference for G. sinensis drought-resistant variety selection and cultivation. The Drought Resistance Index (DRI) served as the primary indicator, supplemented by growth, leaf morphology, and photosynthetic physiological indicators, to thoroughly assess and identify five distinct drought tolerant taxa while also selecting five representative families. Soluble protein (SP), proline (Pro), and malondialdehyde (MDA) contents, as well as the activities of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) in seedlings from the five families, increased as the degree of drought intensified. The highest values were appeared during periods of severe drought, and gradually decreased after subsequent rehydration. Principal component analysis (PCA) revealed MDA and soluble sugars (SS) as the primary predictors of drought and rehydration response in G. sinensis seedlings respectively. Changes in osmoregulatory substance content and increased antioxidant enzyme activity may be crucial for responding to drought tolerance mechanisms. Leaf morphological indicators, seedling height, soil plant analysis development (SPAD) value, photosynthetic indicators, and MDA are dependable parameters for assessing the drought tolerance of G. sinensis seedlings. When assessing the drought-resistance of seedlings using physiological indicators such as photosynthesis, a comprehensive analysis should incorporate multiple indicators and methods. This evaluation approach could serve as a reference for screening exceptional drought-resistant families of G. sinensis.

CRISPR-Cas13a-based detection method for avian influenza virus.

Avian influenza virus (AIV) causes huge losses to the global poultry industry and poses a threat to humans and other mammals. Fast, sensitive, and portable diagnostic methods are essential for efficient avian influenza control. Here, a clustered regularly interspaced short palindromic repeats (CRISPR)-Cas13a based platform was developed to detect AIV. This novel method was developed to specifically detect H1-H16 subtypes of AIV with fluorescence and lateral flow-based readouts and exhibited no cross-reactivity with Newcastle disease virus, avian infectious bronchitis virus, or infectious bursal disease virus. The limit of detection was determined to be 69 and 690 copies/µL using fluorescence and lateral flow as readouts, respectively. The developed assay exhibited 100% consistency with quantitative real-time polymerase chain reaction in detecting clinical samples. The heating of unextracted diagnostic samples to obliterate nuclease treatment was introduced to detect viral RNA without nucleic acid extraction. Single-step optimization was used to perform reverse transcription, recombinase polymerase amplification, and CRISPR-Cas13a detection in a tube. These advances resulted in an optimized assay that could specifically detect AIV with simplified procedures and reduced contamination risk, highlighting the potential to be used in point-of-care testing.

The Seasonal Divergence in the Weakening Relationship between Interannual Temperature Changes and Northern Boreal Vegetation Activity.

The response of boreal vegetation to global warming has shown a weakening trend over the last three decades. However, in previous studies, models of vegetation activity responses to temperature change have often only considered changes in the mean daily temperature (Tmean), with the diurnal temperature range (DTR) being neglected. The goal of this study was to evaluate the temporal trends of the relationships between two temperature factors (Tmean and DTR) and the vegetation activity across the boreal regions on both annual and seasonal timescales, by simultaneously employing satellite and climate datasets. We found that the interannual partial correlation between the growing season (GS) NDVI and Tmean (RNDVI-Tmean) has shown a significant decreasing trend over the last 34 years. At the seasonal scale, the RNDVI-Tmean showed a significant upward trend in the spring, while in the summer and autumn, the RNDVI-Tmean exhibited a significant downward trend. The temporal trend characteristics of the partial correlation between the NDVI and DTR (RNDVI-DTR), at both the GS and seasonal scales, were fully consistent with the RNDVI-Tmean. The area with a significant decrease in the GS RNDVI-Tmean and RNDVI-DTR accounted for approximately 44.4% and 41.2% of the boreal region with the 17-year moving window, respectively. In stark contrast, the area exhibiting a significant increasing trend in the GS RNDVI-Tmean and RNDVI-DTR accounted for only approximately 22.3% and 25.8% of the boreal region with the 17-year moving window, respectively. With respect to the seasonal patterns of the RNDVI-Tmean and RNDVI-DTR, the area with a significant upward trend in the spring was greater than that with a significant downward trend. Nevertheless, more areas had a significant downward trend in the RNDVI-Tmean and RNDVI-DTR in summer and autumn than a significant upward trend. Overall, our research reveals a weakening trend in the impact of temperature on the vegetation activity in the boreal regions and contributes to a deeper understanding of the vegetation response to global warming.

Diversity of lithophytic moss species in karst regions in response to elevation gradients.

The distribution pattern of species diversity along various elevation gradients reflects the biological and ecological characteristics of species, distribution status and adaptability to the environment. Altitude, a comprehensive ecological factor, affects the spatial distribution of species diversity in plant communities by causing integrated changes in light, temperature, water and soil factors. In Guiyang City, we studied the species diversity of lithophytic mosses and the relationships between species and environmental factors. The results showed that: (1) There were 52 species of bryophytes in 26 genera and 13 families within the study area. The dominant families were Brachytheciaceae, Hypnaceae and Thuidiaceae. The dominant genera were Brachythecium, Hypnum, Eurhynchium, Thuidium, Anomodon and Plagiomnium; The dominant species were Eurohypnum leptothallum, Brachythecium salebrosum, Brachythecium pendulum etc. The number of family species and dominant family genera increased first and then decreased with the increase of altitude, and their distribution in elevation gradient III (1334-1515m) was the largest, with 8 families, 13 genera and 21 species. The elevation gradient I (970-1151m) was the least species distributed, with 5 families, 10 genera and 14 species. The dominant species with the largest number in each elevational gradient were Eurohypnum leptothallum, Brachythecium pendulum, Brachythecium salebrosum and Entodon prorepens; (2) There were five kinds of life forms in different elevation gradients, including Wefts, Turfs, Mat, Pendants and Tail. Among them, wefts and turfs appeared in all elevations, while a small amount of Pendants appeared in the area of elevational gradient I (970-1151m), and the most abundant life form was found in the range of elevational gradient III (1334-1515m); (3) Patrick richness index and Shannon-Wiener diversity index were highly significantly (p<0.01) positively correlated, both of which increased and then decreased with elevation, reaching a maximum at elevation gradient III (1334-1515m); The Simpson dominance index had a highly significant (p<0.01) negative correlation with the Patrick richness index and the Shannon-Wiener diversity index, which showed a decreasing and then increasing trend with increasing altitude; Pielou evenness index showed no discernible trend; (4) ß diversity study revealed that while the similarity coefficient tended to decrease with increasing altitude, the species composition of bryophytes increased. The elevation gradient II (1151-1332m) and elevation gradient I (970-1151m) shared the most similarities, whereas elevation gradient III (1515-1694m) and elevation gradient I shared the least similarities (970-1151m). The findings can enrich the theory of the distribution pattern of lithophytic moss species diversity at distinct elevation gradients in karst regions, and serve a scientific and reasonable reference for restoring rocky desertification and protecting biodiversity there.

Comparative Transcriptome Analysis of Gleditsia sinensis Thorns at Different Stages of Development.

G. sinensis thorn (called "zào jiǎo cì", ZJC) has important medicinal and economic value, however, little is known about the molecular mechanisms behind the development of ZJC. In this study, we measured the content of soluble sugar and starch during the growth and development of the thorn, and performed transcriptome sequencing of the thorn segment, non-thorn segment, apex, and root tip at five distinct stages of thorn formation. The results showed that, with the growth of ZJC, the soluble sugar content of the roots, hypocotyls, thorn stems, thornless stems, leaves, and the starch content of the roots and leaves all firstly increased and then decreased after the basic structure of thorns was formed; the soluble sugar content and starch content of ZJC showed an overall downward trend (decreased by 59.26% and 84.56%, respectively). Myb-like, YABBY2, Growth-regulating factor 3, TCP2, Zinc transporter 8, and another 25 genes may be related to the maintenance and growth of thorns. Gene Ontology (GO) enrichment analysis of differentially expressed genes (DEGs) between stems with thorn and thorn-free stems found that a significant number of DEGs were annotated with terms related to the positive regulation of development, heterochronic (GO:0045962), the positive regulation of photomorphogenesis (GO:2000306), and other biological process (BP) terms. The developmental initiation regulation of ZJC may be regulated by TCP transcription factors (TFs). Eight genes were selected randomly to validate the RNA-seq results using real-time quantitative PCR (RT-qPCR) and they indicated that the transcriptome data were reliable. Our work provided a comprehensive review of the thorn development of G. sinensis.

Transcriptome and physiological analyses reveal new insights into delayed incompatibility formed by interspecific grafting.

Pinus elliottii used as rootstock instead of homologous rootstock, have been proved to accelerate early growth of the scion (Pinus massoniana), for cultivation of large diameter wood. However, the basal diameter of scions in heterologous grafts was significantly smaller than self-graft 10 years later, according to field investigation, which was opposed to cultivation objectives. Although advantage of heterologous grafts has been reported, less is known about the long term effect of heterologous rootstock on scions of P. massoniana. The aim of present study was to investigate the mechanism of the above difference. Toward this aim, the growth traits and physiological characteristics of scions in the two graft groups were studied, and the underlying mechanism was preliminarily explored through transcriptome sequencing technology. Results showed that scions of heterologous grafts had less TSCA compared to self-grafts, while no significant difference of plant height, number of branches and canopy volume between two graft groups. Besides, scion leaves of heterologous grafts displayed higher antioxidant enzyme activity and lower chlorophyll content. And interactions between rootstocks and scions had also changed the mineral element composition of scion leaves. Compared with homologous grafts, scion leaves of heterologous grafts accumulated more K+, Mg2+ and Zn2+, but less Ca2+,which have been proved to be conducive to the growth of stem diameter of P. massoniana. Moreover, a comparative transcriptome analysis of two graft groups showed that DEGs between them were mainly caused by the specificity of rootstock. GO and KEGG analysis found that heterologous rootstock had different gene expression preferences, and the gene expression level between rootstocks and scions were significantly different, such as auxin auxin-related genes and stress responsive genes. That may imply that auxin pathway played an important role not only in grafting healing process, but also in maintaining the growth between scion and stock. Summary of all above results, we concluded that the long term effect of heterologous rootstock on scions may be unsatisfactory with the later rapidly growth of scion, probably due to delayed graft incompatibility between scion and stock of heterologous grafts. This study may remind us that the long-term growth of the scion deserves attention as well as the healing process, which could also provide a basis for delayed graft incompatibility.