Forestry research最新文献

Forest plantations, such as poplar and eucalyptus, exhibit high nitrogen requirements that are vital for growth, biomass accumulation, and the production of high-quality timber. However, the investigation of nitrogen use efficiency (NUE) mechanisms in forest plantations lags far behind that in crops. In contrast, natural forest ecosystems, without chemical fertilizer inputs, demonstrate remarkable capacities for biological nitrogen fixation and internal nitrogen cycling. Drawing on nitrogen utilization strategies elucidated in Arabidopsis, crop species, and natural forest ecosystems, this review provides a comprehensive synthesis and proposes strategies to enhance NUE in forest plantations. Key approaches include optimizing root system architecture, increasing intrinsic nitrogen uptake capacity, and harnessing beneficial microorganisms to improve nitrogen utilization. Furthermore, the review highlights the promising opportunities for employing key regulatory genes and synthetic biology approaches to achieve targeted enhancement of NUE in forest plantations.

NAC transcription factors are central regulators of plant salt tolerance, yet their specific roles in ginkgo salt response remain unclear. Here, GbNAC2 was identified as a salinity-induced transcriptional activator in ginkgo, orchestrating two key adaptive responses. GbNAC2 overexpression significantly improved salt tolerance in transgenic plants, accompanied by over 60% increase in root length, and more than 20% increase in flavonoid content compared to wild type (WT). Transcriptome analysis of GbNAC2-overexpressing ginkgo calli revealed that genes related to auxin biosynthesis, and those involved in the flavonoid synthesis pathway, were significantly upregulated in transgenic calli. Mechanistically, GbNAC2 directly binds the GbAREB3 promoter to enhance ABA signaling, and exogenous ABA treatment further enhances salt resilience. The present findings unveil a unique crosstalk mediated by GbNAC2 between flavonoid-antioxidant systems and auxin-ABA hormonal networks, effectively resolving the growth-defense trade-off under salinity in ginkgo.

Conifers pose challenges for breeding programs due to their extended vegetative phases. Despite the critical role of APETALA2 (AP2) in regulating phase transitions, the AP2/ERF superfamily remains largely unexplored in gymnosperms. Here, the first genome-wide analysis of the AP2/ERF superfamily in a conifer, Larix kaempferi (Japanese larch) is presented, and 374 members were identified. Among all eight paralogs, four euAP2 lineage genes, TARGET OF EATs (TOEs), exhibit age-decreased expression patterns. Functional characterization of LkTOE1-2 demonstrates its involvement in somatic embryogenesis and seed germination. Importantly, the RUBY reporter system confirmed an enhanced promoter activity in somatic embryo maturation. Over-expression of LkTOE1-2 in Arabidopsis accelerates seed germination by 23.77%, bolting by 6.93%, and flowering by 5.92%. This study provides not only an expanded genomic resource for gymnosperms but also a candidate gene (LkTOE1-2) to shorten the juvenile phase of larch via molecular breeding.

As climate change accelerates, plant species largely rely on genetic variation to adapt and survive when they fail to track their ecological niches through range shifts. Predicted genomic vulnerability is able to identify populations lacking the necessary genetic variation for climate change adaptation. However, the role of introgression in genomic vulnerability remains poorly explored. Here, we used the dove tree (Davidia involucrata), a relict species native to southwestern China, to test whether introgression may reduce genomic vulnerability. By integrating population genomics and environmental data collected from 196 individuals of 18 populations, we identified 747 strictly climate-associated loci across the distribution range of D. involucrata, 138 of which were recovered from the genetically admixed populations. We estimated the genomic vulnerability for three genetic lineages and two admixed groups using the gradient forest approach, and found that eastern populations are likely to be at higher risk. The eastern admixed populations exhibited a significant reduction, with introgression from the southern lineage. Cumulative importance analysis showed moderate importance for introgressive loci along environmental gradients. This indicates that the introduction of novel alleles through introgression provides only a partial and insufficient counterbalance to the maladaptation observed in D. involucrata under climate change. Our study highlights the role of intraspecific introgression in response to climate change and emphasizes the importance of genomic vulnerability studies in informing conservation practices for relict and endangered species.

N⁵-methylcytosine (m⁵C) RNA methylation plays an essential role in gene regulation, yet its functions in woody plant development remain poorly understood. This study systematically identified 12 putative tRNA-specific methyltransferase 4 (TRM4) homologs (PagTRM4s) within the P. alba × P. glandulosa genome. Phylogenetic and synteny analyses revealed high evolutionary conservation across Arabidopsis and rice. Structural and domain analyses suggested functional conservation among allelic pairs. Expression profiling showed that PagTRM4B-a maintained stable expression in xylem at different developmental stages. PagTRM4B-a overexpression in poplar resulted in decreased plant height and stem diameter, modified wood composition, and increased RNA m⁵C levels. Histological analysis showed that overexpression enhanced xylem cell expansion and secondary xylem formation without affecting cambial activity. Moreover, the expression levels of secondary cell wall (SCW) biosynthesis genes were significantly down-regulated in PagTRM4B-a-OE transgenic plants. This study offers new insights into the epigenetic control of secondary growth in trees and highlights PagTRM4B-a as a potential target for influencing wood formation in woody plants.

To enhance phenotypic plasticity, it is vital to maximize the genetic growth potential of trees and understand their adaptive responses to environmental conditions. Tree species adapt to dynamic environmental conditions by leveraging the interactions among the environment, genotype, and genotype-by-environment. A total of 25 improved varieties of Chinese fir were transplanted and developed through multi-generational breeding into four types of artificial forest soils. Through a quantitative analysis of genotypic, soil environmental conditions, and genotype-by-environment interaction effects on variations in growth, biomass, and root functional traits, the key drivers of phenotypic plasticity were identified. The results indicate that soil environmental conditions and genotype-by-environment interactions are the primary factors influencing trait variation, explaining 55.89% to 93.94% of the observed variation, while the family effect is relatively minor. Notably, pronounced phenotypic plasticity drives divergent selection in both aboveground and belowground growth strategies. Critical traits influencing root dry weight include root average diameter, total root volume, and root-to-shoot ratio. Although root dry weight does not directly affect plant height, it has a substantial impact on aboveground dry weight. These findings highlight that the changes in the aboveground and belowground growth strategies of Chinese fir during the seedling stage are closely linked to the plasticity of root functional traits. For multi-generational genetically improved varieties, this study examined how the integration of genetic effects, soil environmental conditions, and genotype-by-environment interactions in the selection of aboveground growth and root functional traits influences the mechanisms driving biomass accumulation. The results provide actionable insights for selecting soil-specific families in subtropical plantations.

Mixed-species plantations are proven to enhance phosphorus (P) availability in subtropical forest ecosystems. However, the effect of coniferous-broadleaf mixed plantations on soil P cycling dynamics remains poorly understood. Through a long-term field experiment, the study investigated how mixed plantations influence soil P fractions, phoD and pqqC genes, and associated bacterial communities in bulk and rhizosphere soils. Results showed that compared to monocultures, the introduction of broad-leaved trees significantly increased labile P pools, particularly in the rhizosphere. Amplicon-based community profiling of phoD/pqqC genes demonstrated distinct compositional shifts in P-solubilizing bacterial communities across forest types and soil compartments. The pqqC-harboring bacterial communities were more closely related to the P fractions. More importantly, plant properties were important in explaining bulk soil labile P responses, while in rhizosphere soil, labile P was more strongly associated with soil properties, positively affecting labile P. These findings elucidate the complex interplay between tree diversity, microbial functional traits, and soil P transformations. This study underscores the critical role of mixed plantations in promoting microbial-mediated P mobilization and provides valuable insights for designing sustainable forest management strategies to optimize P utilization in subtropical ecosystems.

Structure-based forest management (SBFM) has emerged as an innovative silvicultural approach that optimizes the spatial arrangement of trees to emulate natural forest structures and promote sustainability. Despite increasing applications of SBFM, a comprehensive synthesis of its impacts on stand quality and the underlying mechanisms remains lacking. This review synthesizes 126 peer-reviewed studies (2007-2025) to evaluate the multidimensional effects of SBFM on forest stand growth, structure, soil properties, and stability. Evidence indicates that SBFM enhances tree growth by reducing competitive pressure, improves diameter distribution and species mingling, thereby approximating natural stand patterns, and enriches soil carbon and nutrient pools through increased litter input and microbial activity. These structural adjustments collectively foster a positive feedback loop that integrates aboveground productivity, belowground processes, and overall ecosystem resilience. Future research should prioritize cross-regional ecological monitoring, mechanistic experiments that link structural optimization to biodiversity and carbon sequestration, the integration of artificial intelligence (AI) and remote sensing for precision management, and improvements in forest stand quality evaluation systems. Overall, SBFM markedly improves stand quality and constitutes a promising strategy for sustainable forest management that enhances ecological resilience.

The age biomarker gene PtDAL1 in conifers undergoes expression resetting during pollen maturation, but its regulatory mechanisms remain unclear. This study identifies PtABI3, a B3 transcription factor (TF) in Pinus tabuliformis, as a key repressor of PtDAL1. PtABI3 exhibits strict spatiotemporal complementarity with PtDAL1. Phylogenetic and structural studies revealed PtABI3 as a gymnosperm homolog of angiosperm ABI3, retaining conserved B3 domains critical for DNA binding and transcriptional repression. Ectopic expression of PtABI3 in Arabidopsis recapitulated the classic ABI3 late-flowering phenotype. Mechanistically, PtABI3 directly binds the RY motif (CATGCA) within the PtDAL1 promoter via its B3 domain, as demonstrated by dual-luciferase assays, yeast one-hybrid assays, and electrophoretic mobility shift assays (EMSA). These results revealed that PtABI3 is an evolutionary conserved transcriptional repressor that silences PtDAL1 during pollen maturation, providing the first evidence of B3 TFs mediating age timer gene resetting in conifers. This work bridges gymnosperm and angiosperm regulatory paradigms, highlighting ancient mechanisms for gene expression resetting in plants.

Plant melanin is an organic molecule commonly used in medicine, food, and chemical industries. However, the molecular underpinnings of plant melanin's biosynthesis and its regulation are still unclear. Phyllostachys nigra is well known for its ornamental value because of its black culms. The black pigments enriched in the epidermis and cortex of P. nigra were identified to be melanin by analyses of its physical and chemical properties. Moreover, the biosynthesis of melanin was examined using comprehensive transcriptomic and metabolomic analyses in P. nigra when grown at low temperatures. Nontargeted metabolite profiling revealed that some indoles, including serotonin, 3-indoleacetic acid, and 1H-indole-3-acetamide, were significantly enriched in P. nigra when grown at low temperatures. Parallel transcriptomic analysis showed that a set of structural genes involved in serotonin biosynthesis was significantly upregulated by low temperatures. By integrating the transcriptome data and weighted gene co-expression network analysis, the essential transcription factors that putatively regulate the biosynthesis of serotonins were revealed. Among those, PnWRKY19-3 was functionally tested and shown to increase the serotonin content in transgenic rice by upregulating OsT5H under low temperature conditions. These findings suggest that PnWRKY19-3 may play a positive role in promoting melanin formation in the culms of P. nigra. According to the two functional genomic platforms, it appears that low temperature stimulates melanin formation in P. nigra by inducing the biosynthesis of indoles. Our research provides new insights into melanin biosynthesis in bamboo, which may be vital to other plant species.