Root-soil-microbiome interaction in the rhizosphere of Masson pine (Pinus massoniana) under different levels of heavy metal pollution.

Heavy metal pollution of the soil affects the environment and human health. Masson pine is a good candidate for phytoremediation of heavy metal in mining areas. Microorganisms in the rhizosphere can help with the accumulation of heavy metal in host plants. However, studies on its rhizosphere bacterial communities under heavy metal pollution are still limited. Therefore, in this study, the chemical and bacterial characteristics of Masson pine rhizosphere under four different levels of heavy metal pollution were investigated using 16 S rRNA gene sequencing, soil chemistry and analysis of plant enzyme activities. The results showed that soil heavy metal content, plant oxidative stress and microbial diversity damage were lower the farther they were from the mine dump. The co-occurrence network relationship of slightly polluted soils (C1 and C2) was more complicated than that of highly polluted soils (C3 and C4). Relative abundance analysis indicated Sphingomonas and Pseudolabrys were more abundant in slightly polluted soils (C1 and C2), while Gaiella and Haliangium were more abundant in highly polluted soils (C3 and C4). LEfSe analysis indicated Burkholderiaceae, Xanthobacteraceae, Gemmatimonadaceae, Gaiellaceae were significantly enriched in C1 to C4 site, respectively. Mantel analysis showed that available cadmium (Cd) contents of soil was the most important factor influencing the bacterial community assembly. Correlation analysis showed that eight bacterial genus were significantly positively associated with soil available Cd content. To the best of our knowledge, this is the first study to investigate the rhizospheric bacterial community of Masson pine trees under different degrees of heavy metal contamination, which lays the foundation for beneficial bacteria-based phytoremediation using Masson pines in the future.

Transcriptome-Wide Identification of m6A Writers, Erasers and Readers and Their Expression Profiles under Various Biotic and Abiotic Stresses in Pinus massoniana Lamb.

N6-methyladenosine (m6A) RNA modification is the most prevalent form of RNA methylation and plays a crucial role in plant development. However, our understanding of m6A modification in Masson pine (Pinus massoniana Lamb.) remains limited. In this study, a complete analysis of m6A writers, erasers, and readers in Masson pine was performed, and 22 m6A regulatory genes were identified in total, including 7 m6A writers, 7 m6A erases, and 8 readers. Phylogenetic analysis revealed that all m6A regulators involved in Masson pine could be classified into three distinct groups based on their domains and motifs. The tissue expression analysis revealed that the m6A regulatory gene may exert a significant influence on the development of reproductive organs and leaves in Masson pine. Moreover, the results from stress and hormone expression analysis indicated that the m6A regulatory gene in Masson pine might be involved in drought stress response, ABA-signaling-pathway activation, as well as resistance to Monochamus alternatus. This study provided valuable and anticipated insights into the regulatory genes of m6A modification and their potential epigenetic regulatory mechanisms in Masson pine.

Assessment of tree-ring mercury radial translocation and age effect in Masson pine: Implications for historical atmospheric mercury reconstruction.

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury (Hg) trends, but with the large knowledge gaps in the reliability. In this study, we comprehensively evaluated the Hg source, radial translocation and age effect of Masson pine (Pinus massoniana) tree ring at Mt. Jinyun in Chongqing, to assess the suitability of such tree ring as the archive of atmospheric Hg. Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles. The Hg concentration significantly increased along with stem height (P < 0.05), indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg. We found a distinct age effect that the tree ring of young trees had the higher Hg concentration. Besides, we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings. The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing. We finally suggest that in further Hg dendrochemistry, better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

The miRNA-mRNA Regulatory Modules of Pinus massoniana Lamb. in Response to Drought Stress.

Masson pine (Pinus massoniana Lamb.) is a major fast-growing woody tree species and pioneer species for afforestation in barren sites in southern China. However, the regulatory mechanism of gene expression in P. massoniana under drought remains unclear. To uncover candidate microRNAs, their expression profiles, and microRNA-mRNA interactions, small RNA-seq was used to investigate the transcriptome from seedling roots under drought and rewatering in P. massoniana. A total of 421 plant microRNAs were identified. Pairwise differential expression analysis between treatment and control groups unveiled 134, 156, and 96 differential expressed microRNAs at three stages. These constitute 248 unique microRNAs, which were subsequently categorized into six clusters based on their expression profiles. Degradome sequencing revealed that these 248 differentially expressed microRNAs targeted 2069 genes. Gene Ontology enrichment analysis suggested that these target genes were related to translational and posttranslational regulation, cell wall modification, and reactive oxygen species scavenging. miRNAs such as miR482, miR398, miR11571, miR396, miR166, miRN88, and miRN74, along with their target genes annotated as F-box/kelch-repeat protein, 60S ribosomal protein, copper-zinc superoxide dismutase, luminal-binding protein, S-adenosylmethionine synthase, and Early Responsive to Dehydration Stress may play critical roles in drought response. This study provides insights into microRNA responsive to drought and rewatering in Masson pine and advances the understanding of drought tolerance mechanisms in Pinus.

Physiological, Proteomic, and Resin Yield-Related Genes Expression Analysis Provides Insights into the Mechanisms Regulating Resin Yield in Masson Pine.

Masson pine (Pinus massoniana Lamb.) is an important resin-producing conifer species in China. Resin yield is a highly heritable trait and varies greatly among different genotypes. However, the mechanisms regulating the resin yield of masson pine remain largely unknown. In this study, physiological, proteomic, and gene expression analysis was performed on xylem tissues of masson pine with high and low resin yield. Physiological investigation showed that the activity of terpene synthase, as well as the contents of soluble sugar, jasmonic acid (JA), methyl jasmonate (MeJA), gibberellins (GA1, GA4, GA9, GA19, and GA20), indole-3-acetic acid (IAA), and abscisic acid (ABA) were significantly increased in the high yielder, whereas sucrose and salicylic acid (SA) were significantly decreased compared with the low one. A total of 2984 differentially expressed proteins (DEPs) were identified in four groups, which were mainly enriched in the biosynthesis of secondary metabolites, protein processing in the endoplasmic reticulum, carbohydrate metabolism, phytohormone biosynthesis, glutathione metabolism, and plant-pathogen interaction. Integrated physiological and proteomic analysis revealed that carbohydrate metabolism, terpenoid biosynthesis, resistance to stress, as well as JA and GA biosynthesis and signaling, play key roles in regulating resin yield. A series of proteins associated with resin yield, e.g., terpene synthase proteins (TPSs), ATP-binding cassette transporters (ABCs), glutathione S-transferase proteins (GSTs), and heat shock proteins (HSPs), were identified. Resin yield-related gene expression was also associated with resin yield. Our study unveils the implicated molecular mechanisms regulating resin yield and is of pivotal significance to breeding strategies of high resin-yielding masson pine cultivars.

Insights into Enhanced Peroxydisulfate Activation with B and Fe Co-Doped Biochar from Bark for the Rapid Degradation of Guaiacol.

A boron and iron co-doped biochar (B-Fe/biochar) from Masson pine bark was fabricated and used to activate peroxydisulfate (PDS) for the degradation of guaiacol (GL). The roles of the dopants and the contribution of the radical and non-radical oxidations were investigated. The results showed that the doping of boron and iron significantly improved the catalytic activity of the biochar catalyst with a GL removal efficiency of 98.30% within 30 min. The degradation of the GL mainly occurred through the generation of hydroxyl radicals (·OHs) and electron transfer on the biochar surface, and a non-radical degradation pathway dominated by direct electron transfer was proposed. Recycling the B-Fe/biochar showed low metal leaching from the catalyst and satisfactory long-term stability and reusability, providing potential insights into the use of metal and non-metal co-doped biochar catalysts for PDS activation.

Competitive performance of Pinus massoniana is related to scaling relationships at the individual plant and branch levels.

PREMISE: Competition is an important driver of tree mortality and thus affects forest structure and dynamics. Tree architectural traits, such as height-to-diameter (H-D) and branch length-to-diameter (L-d) relationships are thought to influence species competitiveness by affecting light capture. Unfortunately, little is known about how the H vs. D and L vs. d scaling exponents are related to tree performance (defined in the context of growth vigor) in competition. METHODS: Using data from field surveys of 1547 individuals and destructive sampling of 51 trees with 1086 first-order branches from a high-density Pinus massoniana forest, we explored whether the H vs. D and the L vs. d scaling exponents respectively differed numerically across tree performance and branch vertical position in crowns. RESULTS: The results indicated that (1) the H vs. D scaling exponent decreased as tree performance declined; (2) the L vs. d scaling exponent differed across tree performance classes (i.e., the scaling exponent of "inferior" trees was significantly larger than that of "moderate" and "superior" trees); (3) the L vs. d scaling exponent decreased as branch position approached ground level; and (4) overall, the branch scaling exponent decreased as tree performance improved in each crown layer, but decreased significantly in the intermediate layer. CONCLUSIONS: This study highlights the variation within (and linkage among) length-to-diameter scaling relationships across tree performance at the individual and branch levels. This linkage provides new insights into potential mechanisms of tree growth variation (and even further mortality) under competition in subtropical forests.

Protoplast isolation and transcriptome analysis of developing xylem in Pinus massoniana (Pinaceae).

BACKGROUND: With active physiological and biochemical activities, tissue-specific protoplasts from cambial derivatives, could serve as a specific source for information on xylogenesis for softwood species resistant to stable genetic transformation and lacking available mutants. METHODS AND RESULTS: In this study, protoplasts were isolated from developing xylem of the Chinese red pine, Pinus massoniana, by enzymolysis. High-quality RNAs were extracted from developing xylem and their protoplasts for constructing transcriptome libraries. Using Illumina HiSeq 2500 PE150 platform, a total of 362,328,426 clean paired-end reads (54.35G) were generated from multiple cDNA libraries and assembled into 146,422 unigenes. The transcriptome data were further analysed to identify 1567 differentially expressed genes (DEGs) between the isolated protoplasts and developing xylem of P. massoniana (Masson pine), 1126 DEGs were upregulated in protoplasts relative to developing xylem cells and 441 were downregulated. Most of the differentially expressed genes in biological process terms are related to plant response, which may be due to the response to cell wall removal. Further, the expression pattern of 71 unigenes involved in lignin biosynthesis was verified by RNA-seq. CONCLUSIONS: This study is the first to report the transcriptome profiles of the developing xylem and its protoplasts of coniferous trees, which provide a new perspective and valuable resource for tracking transcriptional regulatory events in wood formation of Masson pine.

Acclimation Strategy of Masson Pine (Pinus massoniana) by Limiting Flavonoid and Terpenoid Production under Low Light and Drought.

Low light and drought often limit the growth and performance of Masson pines (Pinus massoniana) in the subtropical forest ecosystem of China. We speculated that stress-induced defensive secondary metabolites, such as flavonoids and terpenoids, might influence the growth of Masson pines, considering the existence of tradeoffs between growth and defense. However, the mechanisms of Masson pines responsive to low light and drought at the levels of these two metabolites remain unclear. In the present work, the compositions of flavonoids and terpenoids, as well as their biosynthetic pathways, were revealed through metabolome and transcriptome analyses, respectively, coupled with a study on carbon allocation using a 13CO2-pulse-labeling experiment in two-year-old seedlings under low light (LL), drought (DR), and their combined stress (DL) compared to a control (CK). A total of 35 flavonoids and derivatives (LL vs. CK: 18; DR vs. CK: 20; and DL vs. CK: 18), as well as 29 terpenoids and derivatives (LL vs. CK: 23; DR vs. CK: 13; and DL vs. CK: 7), were differentially identified in the leaves. Surprisingly, most of them were decreased under all three stress regimes. At the transcriptomic level, most or all of the detected DEGs (differentially expressed genes) involved in the biosynthetic pathways of flavonoids and terpenoids were downregulated in phloem and xylem under stress treatments. This indicated that stress treatments limited the production of flavonoids and terpenoids. The reduction in the 13C allocation to stems might suggest that it is necessary for maintaining the growth of Masson pine seedlings at the whole-plant level by attenuating energetic resources to the biosynthetic pathways of flavonoids and terpenoids when facing the occurrence of adverse environments. Our results provide new insight into understanding the acclimation strategy of Masson pines or other conifers in adverse environments.

Identification of Genes and Metabolic Pathways Involved in Resin Yield in Masson Pine by Integrative Analysis of Transcriptome, Proteome and Biochemical Characteristics.

Masson pine (Pinus massoniana L.) is one of the most important resin-producing tree species in southern China. However, the molecular regulatory mechanisms of resin yield are still unclear in masson pine. In this study, an integrated analysis of transcriptome, proteome, and biochemical characteristics from needles of masson pine with the high and common resin yield was investigated. The results showed that chlorophyll a (Chl a), chlorophyll b (Chl b), total chlorophyll (Chl C), carotenoids (Car), glucose (Glu), gibberellin A9 (GA9), gibberellin A15 (GA15), and gibberellin A53 (GA53) were significantly increased, whereas fructose (Fru), jasmonic acid (JA), jasmonoyl-L-isoleucine (JA-ILE), gibberellin A1 (GA1), gibberellin A3 (GA3), gibberellin A19 (GA19), and gibberellin A24 (GA24) were significantly decreased in the high resin yield in comparison with those in the common one. The integrated analysis of transcriptome and proteome showed that chlorophyll synthase (chlG), hexokinase (HXK), sucrose synthase (SUS), phosphoglycerate kinase (PGK), dihydrolipoamide dehydrogenase (PDH), dihydrolipoamide succinyltransferase (DLST), 12-oxophytodienoic acid reductase (OPR), and jasmonate O-methyltransferases (JMT) were consistent at the transcriptomic, proteomic, and biochemical levels. The pathways of carbohydrate metabolism, terpenoid biosynthesis, photosynthesis, and hormone biosynthesis may play crucial roles in the regulation of resin yield, and some key genes involved in these pathways may be candidates that influence the resin yield. These results provide insights into the molecular regulatory mechanisms of resin yield and also provide candidate genes that can be applied for the molecular-assisted selection and breeding of high resin-yielding masson pine.

Uncovering miRNA-mRNA Regulatory Modules in Developing Xylem of Pinus massoniana via Small RNA and Degradome Sequencing.

Xylem is required for the growth and development of higher plants to provide water and mineral elements. The thickening of the xylem secondary cell wall (SCW) not only improves plant survival, but also provides raw materials for industrial production. Numerous studies have found that transcription factors and non-coding RNAs regulate the process of SCW thickening. Pinus massoniana is an important woody tree species in China and is widely used to produce materials for construction, furniture, and packaging. However, the target genes of microRNAs (miRNAs) in the developing xylem of P. massoniana are not known. In this study, a total of 25 conserved miRNAs and 173 novel miRNAs were identified via small RNA sequencing, and 58 differentially expressed miRNAs were identified between the developing xylem (PM_X) and protoplasts isolated from the developing xylem (PM_XP); 26 of these miRNAs were significantly up-regulated in PM_XP compared with PM_X, and 32 were significantly down-regulated. A total of 153 target genes of 20 conserved miRNAs and 712 target genes of 113 novel miRNAs were verified by degradome sequencing. There may be conserved miRNA-mRNA modules (miRNA-MYB, miRNA-ARF, and miRNA-LAC) involved in softwood and hardwood formation. The results of qRT-PCR-based parallel validation were in relatively high agreement. This study explored the potential regulatory network of miRNAs in the developing xylem of P. massoniana and provides new insights into wood formation in coniferous species.

Comparing ameliorative effects of biomass ash and alkaline slag on an acidic Ultisol under artificial Masson pine: A field experiment.

Forest soil acidification caused by acid deposition is a serious threat to the forest ecosystem. To investigate the liming effects of biomass ash (BA) and alkaline slag (AS) on the acidic topsoil and subsoil, a three-year field experiment under artificial Masson pine was conducted at Langxi, Anhui province in Southern China. The surface application of BA and AS significantly increased the soil pH, and thus decreased exchangeable acidity and active Al in the topsoil. Soil exchangeable Ca2+ and Mg2+ in topsoil were significantly increased by the surface application of BA and AS, while an increase in soil exchangeable K+ was only observed in BA treatments. The soil acidity and active Al in subsoil were decreased by the surface application of AS. Compared with the control, soluble monomeric and exchangeable Al in the subsoil was decreased by 38.0% and 29.4% after 3 years of AS surface application. There was a minimal effect on soluble monomeric and exchangeable Al after the application of BA. The soil exchangeable Ca2+ and Mg2+ in the subsoil increased respectively by 54% and 141% after surface application of 10 t ha-1 AS. The decrease of soil active Al and increase of base cations in subsoil were mainly attributed to the high migration capacity of base cations in AS. In conclusion, the effect of surface application of AS was superior to BA in ameliorating soil acidity and alleviating soil Al toxicity in the subsoil of this Ultisol.

A new aphelench nematode, Basilaphelenchus brevistylus n. sp. (Aphelenchoididae: Tylaphelenchinae) from Pinus massoniana in China.

Basilaphelenchus brevistylus n. sp. was isolated from masson pine (Pinus massoniana) in Guangdong province, China. The new species is characterized by an offset lip region, short stylet (female stylet 4.5-5.5 µm and male stylet 4-5 µm long) with three elongate posteriorly directed knobs, posteriorly located metacorpal valve and lateral field composed of three lines. The female has an elongate postuterine sac and a short conical tail, uniformly narrowing toward a sharp tip, or tapering to a slightly offset mucronate tip in a few individuals. The male has a conical tail with a sharp terminal mucro, three pairs of caudal papillae, and small arcuate spicules with a bluntly rounded condylus and small pointed rostrum. B. brevistylus n. sp. can be distinguished from all described Basilaphelenchus nematodes by numerous morphological and morphometrical traits, especially the tail morphology of both sexes and stylet length. In addition, molecular phylogenetic trees inferred from rRNA small subunit and D2-D3 expansion domains of large subunit revealed that this nematode belongs to the Basilaphelenchus, and is clearly different from all the other Basilaphelsenchus species.

Proteomic analyses provide new insights into the responses of Pinus massoniana seedlings to phosphorus deficiency.

Phosphorus is an essential macronutrient for plant growth and development. Plants can respond defensively to phosphorus deficiency by modifying their morphology and metabolic pathways via the differential expression of low phosphate responsive genes. To better understand the mechanisms by which the Masson pine (Pinus massoniana) adapts to phosphorus deficiency, we conducted comparative proteomic analysis using an elite line exhibiting high tolerance to phosphorus deficiency. The selected seedlings were treated with 0.5 mM KH2PO4 (control), 0.01 mM KH2PO4 (P1), or 0.06 mM KH2PO4 (P2) for 48 days. Total protein samples were separated via 2DE. A total of 98 differentially expressed proteins, which displayed at least 1.7-fold change expression compared to the control levels (p ≤ 0.05), were identified by MALDI-TOF/TOF MS. These phosphate starvation responsive proteins were implicated in photosynthesis, defense, cellular organization, biosynthesis, energy metabolism, secondary metabolism, signal transduction etc. Therefore, these proteins might play important roles in facilitating internal phosphorus homeostasis. Additionally, the obtained data may be useful for the further characterization of gene function and may provide a foundation for a more comprehensive understanding of the adaptations of the Masson pine to phosphorus-deficient conditions.

Ecological stoichiometry of C, N, P and Si of Karst Masson pine forests: Insights for the forest management in southern China.

Ecological stoichiometry is an effective method to study the stoichiometric relations and laws of elements in biogeochemical cycle, widely used in studies on nutrient cycles, limiting elements and nutrient utilization efficiency in ecosystems. To explore C, N, P, and Si stoichiometric characteristics and reveal these nutrient cycle processes and mechanisms in the karst Masson pine forests, the typical Masson pine forests of the three different stand ages in southern China were selected as the research objects and the C, N, P, and Si stoichiometric characteristics of soil-plant-litter continuum were studied. The followed results and conclusions were obtained: 1) Content range of TOC (total organic carbon), TN (total N), TP (Total P) and TSi (total Si) of the Masson pine forests was 288.31-334.61, 0.34-6.66, 0.11-1.05, and 0.76-11.4 g·kg-1, respectively. And the ratio range of C:N, C:P, C:Si, N:P, N:Si, and P:Si was 49.95-913.57, 99.98-2872.18, 22.48-429.31, 1.85-6.33, 0.17-6.01, and 0.04-0.91, respectively. 2) The significant differences in C, N, P, and Si stoichiometric characteristics were present between different organs or different forest ages. Leaves had the highest N and P content, while roots were the best enriched organ of Si element. Si content and C:Si were obviously correlated with forest age. 3) Significant N limitation was present in the Masson pine forests. And in the young and middle-aged forests, N limitation was more obvious. 4) The litter nutrients mainly came from branches. And the litter decomposed fast, which played an important role in the nutrient return of barren karst soil. The present results not only revealed the stoichiometric characteristics and cycling processes of C, N, P, and Si elements in the Masson pine forests, but also provided important scientific bases for the artificial management of Masson pine plantations in southern China.

Transcription Factor and Protein Regulatory Network of PmACRE1 in Pinus massoniana Response to Pine Wilt Nematode Infection.

Pine wilt disease, caused by Bursaphelenchus xylophilus, is a highly destructive and contagious forest affliction. Often termed the "cancer" of pine trees, it severely impacts the growth of Masson pine (Pinus massoniana). Previous studies have demonstrated that ectopic expression of the PmACRE1 gene from P. massoniana in Arabidopsis thaliana notably enhances resistance to pine wilt nematode infection. To further elucidate the transcriptional regulation and protein interactions of the PmACRE1 in P. massoniana in response to pine wilt nematode infection, we cloned a 1984 bp promoter fragment of the PmACRE1 gene, a transient expression vector was constructed by fusing this promoter with the reporter GFP gene, which successfully activated the GFP expression. DNA pull-down assays identified PmMYB8 as a trans-acting factor regulating PmACRE1 gene expression. Subsequently, we found that the PmACRE1 protein interacts with several proteins, including the ATP synthase CF1 α subunit, ATP synthase CF1 ß subunit, extracellular calcium-sensing receptor (PmCAS), caffeoyl-CoA 3-O-methyltransferase (PmCCoAOMT), glutathione peroxidase, NAD+-dependent glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase 1, cinnamyl alcohol dehydrogenase, auxin response factor 16, and dehydrin 1 protein. Bimolecular fluorescence complementation (BiFC) assays confirmed the interactions between PmACRE1 and PmCCoAOMT, as well as PmCAS proteins in vitro. These findings provide preliminary insights into the regulatory role of PmACRE1 in P. massoniana's defense against pine wilt nematode infection.

Corrigendum: Forest stand spectrum reconstruction using spectrum spatial feature gathering and multilayer perceptron.

[This corrects the article DOI: 10.3389/fpls.2023.1223366.].

Pest categorisation of Dendrolimus punctatus.

The EFSA Panel on Plant Health performed a pest categorisation of Dendrolimus punctatus (Lepidoptera: Lasiocampidae), following a commodity risk assessment of bonsai Pinus parviflora grafted onto P. thunbergii from China, in which D. punctatus was identified as a pest of possible concern to the European Union (EU). D. punctatus, also known as the Masson pine caterpillar, is present in China, Taiwan, Vietnam, India and has recently spread to Japanese islands close to Taiwan. Larval feeding on the needles of Pinus elliottii, P. luchuensis, P. massoniana, P. merkusii and P. tabulaeformis causes important damage. D. punctatus larvae can also feed on P. armandii, P. echinata, P. latteri, P. parviflora, P. sylvestris var. mongolica, P. taeda, P. taiwanensis and P. thunbergii, but full development on these hosts is uncertain. The pest has three to five generations per year; winter is spent as larvae on branch tips, on tree trunks and in the soil. The females lay egg clusters on pine needles. Pupation occurs in cocoons attached to branches or needles. D. punctatus could enter the EU either as eggs, larvae or pupae in the foliage of plants for planting or cut branches, as larvae on wood with bark or as overwintering larvae in branches, crevices in the bark or in the litter of potted plants. However, Annex VI of 2019/2072 prohibits the introduction of D. punctatus hosts (Pinus spp.) from countries and areas where the pest occurs. There are climate zones where the pest occurs in Asia that also occur in the EU, though they are limited, which constitutes an uncertainty regarding establishment. The pest's main hosts are not grown in the EU. However, the fact that it attacks the North American Pinus echinata, P. elliottii and P. taeda in its Asian native area suggests a potential capacity to shift to pine species occurring in the EU territory. D. punctatus satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. Whether the Pinus commonly found in Europe could act as hosts is unknown but is fundamental, affecting the criteria of establishment and magnitude of impact.

Ecological Stoichiometry and Stock Distribution of C, N, and P in Three Forest Types in a Karst Region of China.

Ecological stoichiometry plays important roles in understanding the nutrient constraints on tree growth and development, as well in maintaining ecosystem services in forests, yet the characteristics of carbon:nitrogen:phosphorous (C:N:P) stoichiometry in forests under karst environment have not been sufficiently evaluated. In this study, concentration, distribution, stocks of Nitrogen (N) and Phosphorous (P), and ecological stoichiometry were studied in three common forest types: Masson pine natural forests (MPNF), Masson pine plantation forests (MPPF), and Slash pine plantation forests (SPPF) in a karst region of southwestern China. Results showed that N concentrations were higher in overstory than in understory and litter in the studied forests. However, P concentration was relatively low in overstory component of the forested ecosystems. Meanwhile, the N and P concentrations were higher in SPPF in the stem and litter, while these contents were higher in MPPF and MPNP in the overstory and understory. The N and P stocks ranged from 5.7-6.2 t ha-1, and 0.5-0.6 t ha-1 in the examined forests. The ecological stoichiometry of C:N:P in the three forest types was similar in litter (46-49:2:1), and relatively steady in soil (250-320:13-16:1) and tree leaf (100-200:14-20:1). Soil P status was the primary limiting factor in affecting tree growth in MPPF and SPPF (N:P ratio > 16), while both N and P conditions were the main restrictive factors in MPNP (N:P ratio = 15) in the study area. Our study provides scientific references and useful datasets of C:N:P stoichiometry for sustainable management of forest ecosystems in karst regions.

Masson pine pollen aqueous extract ameliorates cadmium-induced kidney damage in rats.

Introduction: Cadmium (Cd) is a hazardous environmental pollutant present in soil, water, and food. Accumulation of Cd in organisms can cause systematic injury and damage to the kidney. The Masson pine pollen aqueous extract (MPPAE) has attracted increasing attention due to its antioxidant activity and ability to enhance immunity. Methods: In this study, we investigated the potential of MPPAE to protect against Cd-induced kidney damage in rats and the underlying mechanism. The transcriptome and metabolome of rats with Cd-induced kidney damage, following treatment with MPPAE, were explored. Results: The concentrations of superoxide dismutase (SOD) and malondialdehyde (MDA) were both significantly altered after treatment with MPPAE. Furthermore, sequencing and analysis of the transcriptome and metabolome of rats with Cd-induced kidney damage, following treatment with MPPAE, revealed differential expression of numerous genes and metabolites compared with the untreated control rats. These differentially expressed genes (DEGs) included detoxification-related genes such as cytochrome P450 and the transporter. The differentially expressed metabolites (DEMs) included 4-hydroxybenzoic acid, L-ascorbate, and ciliatine. Conjoint transcriptome and metabolome analysis showed that several DEGs were correlated with DEMs. Conclusion: These preliminary findings indicate the potential of MPPAE for the treatment of toxic metal poisoning.