According to the ‘novel weapons hypothesis’, invasive success depends on harmful plant biochemicals, including allelopathic antimicrobial roots exudate that directly inhibit plant growth and soil microbial activity. However, the combination of direct and soil-mediated impacts of invasive plants via allelopathy remains poorly understood. Here, we addressed the allelopathic effects of an invasive plant species (Rhus typhina) on a cultivated plant (Tagetes erecta), soil properties and microbial communities. We grew T. erecta on soil samples at increasing concentrations of R. typhina root extracts and measured both plant growth and soil physiological profile with community-level physiological profiles (CLPP) using Biolog Eco-plates incubation. We found that R. typhina root extracts inhibit both plant growth and soil microbial activity. Plant height, Root length, soil organic carbon (SOC), total nitrogen (TN) and AWCD were significantly decreased with increasing root extract concentration, and plant above-ground biomass (AGB), below-ground biomass (BGB) and total biomass (TB) were significantly decreased at 10 mg·mL^-1 of root extracts. In particular, root extracts significantly reduced the carbon source utilization of carbohydrates, carboxylic acids and polymers, but enhanced phenolic acid. Redundancy analysis shows that soil pH, TN, SOC and EC were the major driving factors of soil microbial activity. Our results indicate that strong allelopathic impact of root extracts on plant growth and soil microbial activity by mimicking roots exudate, providing novel insights into the role of plant–soil microbe interactions in mediating invasion success.

Transcription factors play a key role in plant growth and development. As the largest family of plant-specific transcription factors, the NAC family plays a central role in coordinating plant growth and development and environmental adaptation through its unique molecular design paradigm of “fixed N-terminal structural domain + variable C-terminal regulatory domain”. This review systematically analyses the multidimensional regulatory mechanisms of NAC transcription factors in developmental processes such as cell wall remodelling, root system architecture, leaf senescence and fruit ripening, and reveals their molecular basis for responding to biotic/abiotic stresses through strategies such as hormone signalling integration (ABA, SA, JA, etc.), antioxidant defence activation and metabolic reprogramming. The study found that NAC proteins precisely control plant growth through multiple regulatory mechanisms and have evolved to form both conservative and diverse functional modules, which are of great value for crop improvement. However, research still faces three major challenges: the NAC regulatory network in different crops is still unclear, the coordinated response to multiple stresses has not been solved, and the ecological risks of gene editing have not been assessed. To this end, this paper proposes to build an ‘NAC regulatory map database’ and use synthetic biology and artificial intelligence technology to design smarter, stress-tolerant and high-yielding crops, overcoming the limitations of traditional research.

Atmospheric nitrogen deposition affects the health of forest ecosystems by altering soil microbial activity. However, the effects of nitrogen addition levels, morphology and ecosystem type on whether nitrogen addition is beneficial or detrimental to soil health is controver-sial, and most studies have focused on the negative effects on microbial structure. Based on this, this study conducted a four-year experiment of nitrogen (NaNO₃) addition at two levels (10 and 20 kg N hm⁻²·yr⁻¹) in the understory soil of Larix olgensis in northeastern China to study soil microbial properties, soil enzyme activities, and to analyze soil physi-cochemical properties and the correlation between them. The results showed that nitrogen addition reduced soil pH and increased soil NH₄⁺-N and NO₃⁻-N contents, thus promoting the activities of Urease (Ure), Acid phosphatase (ACP) and N-Acetamidoglucosidase (NAG) and inhibiting the activity of Leucine aminopeptidase (LAP) in soil, further improving the diversity and richness of soil microorganisms and increasing the dominant taxa of beneficial microorganisms. This may be due to soil acidification caused by the addition of nitrogen, which increases the effectiveness of nitrogen in the soil, improving soil properties, moving soil health in a beneficial direction, promoting beneficial microbial activity, and making the soil more suitable for the growth of the acid-loving tree species L. olgensis. In general, N addition favored the development of soil bacterial communities and the maintenance of soil nutrient status, and had a positive effect on the soil nutrient status of L. olgensis. The results of this study may provide an important scientific basis for adaptive management of forest ecosystems in the context of global nitrogen deposition.

Atmospheric nitrogen deposition can alter soil microbial communities and further impact the structure and function of forest ecosystems. However, most studies are focused on positive or negative effects after nitrogen addition, and few studies pay attention to its interruption. In order to investigate whether interruption after different levels of short-term N additions still benefit soil health, we conducted a 2-year interruption after a 4-year short-term nitrogen addition (10 and 20 kg N·hm⁻²·yr⁻¹) experiment; then, we compared soil microbial diversity and structure and analyzed soil physicochemical properties and their correlations before and after the interruption in Larix olgensis forest soil in northeast China. The results showed that soil ecological stabilization of Larix olgensis forest further improved after the interruption compared to pre-interruption. The TN, C:P, N:P, and C:N:P ratios increased significantly regardless of the previous nitrogen addition concentration, and soil nutrient cycling was further promoted. The relative abundance of the original beneficial microbial taxa Gemmatimonas, Sphingomonas, and Pseudolabrys increased; new beneficial bacteria Ellin6067, Massilia, Solirubrobacter, and Bradyrhizobium appeared, and the species of beneficial soil microorganisms were further improved. The results of this study elucidated the dynamics of the bacterial community before and after the interruption of short-term nitrogen addition and could provide data support and a reference basis for forest ecosystem restoration strategies and management under the background of global nitrogen deposition.

The ascorbate (AsA)–glutathione (GSH) metabolism pathway is an important antioxidant system in cadmium (Cd) detoxification; the AsA–GSHpathway is generally regulated by a specific set of functional genes. However, transcription factors involved in AsA–GSH pathway have yet to be identified. Herein, we transformed a heat shock transcription factor SpHsfA4c from Sedum plumbizincicola into Populus. × canescens. Under 100 μM CdCl₂ stress for 30 d, the leaf chlorosis of wild-type poplars (WT) is more serious than that in transgenic poplars. The root biomass, shoot biomass and tolerance index (TIs) of transgenic poplars were higher than those in WT. In addition, transgenic poplars have higher Cd²⁺ uptake and Cd content. Compared with WT, the contents of hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−) in transgenic poplars were significantly reduced in leaves under Cd treatment. The expression levels of five enzymes (ascorbate peroxidase (APX), catalases (CAT), superoxide dismutase (SOD), peroxidase (POD) and glutathione S-transferase (GST)) were higher in transgenic poplars than those in WT. Transgenic poplars contained higher concentrations of intermediate metabolites, including GSH, AsA and phytochelatins (PCs), and a higher GSH/GSSG ratio in the AsA–GSH metabolism pathway. In Fourier transform infrared (FTIR) spectra, the characteristic peaks indicated that the contents of cysteine, GSH and AsA in transgenic poplars were exceeded compared to those in WT. These results suggested that SpHsfA4c can activate the AsA–GSH metabolism pathway to reduce Cd-associated oxidative stress. Therefore, overexpressing SpHsfA4c in P. × canescens can give rise to a superior Cd tolerance. Our results provide a theoretical significance for breeding potential new germplasm resources with high biomass and high Cd tolerance for remediation of soil heavy metal pollution.

Climate change and anthropogenic nitrogen addition alter the soil physicochemical properties and microbial activity in oligotrophic forest soil. Unbalanced and non-selective nitrogen fertilizer application is lost as gas emissions (N₂O, NO) and also contributed to eutrophication through NO₃⁻ leachate. Similarly, NO₃⁻ infiltrates and contaminated drinking water sources lead to human thyroid dysfunction. In order to protect depleting timber growth due to nitrogen deficiency and increasing ecological concerns from nitrogen misapplication, we reviewed the effects of different synthetic nitrogen forms and levels on the biogeochemical process. In this review, we focused on the most recent findings from research articles, review articles, and meta-analyses on forest soil and also followed the complementary insights from agricultural soil so that we may be able to highlight how these observations contribute to the understanding of the forest soil nitrogen cycle. Firstly, we elaborated the role of nitrification and denitrification in the nitrogen transformation process. Secondly, we discussed the effect of different nitrogen forms and levels on nitrification and denitrification functional gene abundances. Thirdly, we analyzed the possible effect of gene abundances on the nitrogen conversion process. Finally, we revealed that different forms and levels of synthetic nitrogen not only alter the nitrogen conversion pathways by increasing the gene abundances through substrate availability but also shift the gene dominance, thereby modifying soil physicochemical properties, such as pH. This collectively changes the conditions, which are critical for gene expression potential involved in the nitrogen conversion process. These findings may create a direction for sustainable and eco-friendly fertilizer application in nitrogen-deficient soil.