Mulching, a widely recognized agricultural practice, involves covering the soil surface with organic or inorganic materials to enhance soil properties and optimize growing conditions. This practice has demonstrably positive effects on soil physicochemical and biological properties, leading to reduced evaporation and weed suppression. This study investigated the effects of grass mulching (GV, Vulpia myuros) versus clean tillage (CK) on soil properties, microbial communities, and fruit quality in a red mandarin orchard. Grass mulching significantly enhanced the surface soil nutrients (0–20 cm), alkali-hydrolyzable nitrogen (AN, 105.5%), available phosphorus (AP, 144.4%), available potassium (AK, 102.1%), soil organic matter (SOM, 42.5%), total organic carbon (TOC, 93.1%), and enzyme activities, i.e., alkaline phosphatase (60.1%), urease (39.3%), and soil deep layer (20–40 cm) showing lower but notable improvements of available phosphorus (116.6%), total organic carbon (101.9%), respectively. Grass mulching enhanced the Proteobacteria abundance (soil surface 36 to 39%, & deep 33 to 37%) and altered fungal dominance (surface: unclassified_Agaricomycetes, deep: Mortierella). Beta diversity revealed distinct microbial clustering between treatments. Soil physicochemical properties (alkali-hydrolyzable nitrogen, electrical conductivity and soil organic matter) strongly correlated with unclassified_Micropepsaceae and Agaricomycetes. Grass mulching improved fruit quality, increased vitamin C (24.5%), and decreased pericarp thickness (27.1%), with bacterial communities showing stronger fruit quality correlations than fungi. These results demonstrated that the grass mulching enhances soil fertility, microbial activity and fruit quality, supporting its adoption in sustainable citrus cultivation in the years to come.

The N⁶-methyladenosine (m⁶A) methylation of mRNA is involved in biological processes essential for plant growth. To explore the m⁶A modification of sugarcane and reveal its regulatory function, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was used to construct the m⁶A map of sugarcane. In this study, m⁶A sites of sugarcane transcriptome were significantly enriched around the stop codon and within 3′-untranslated regions (3′UTR). Gene ontology (GO) analysis showed that the m⁶A modification genes are associated with metabolic biosynthesis. In addition, the m⁶A modification of drought-resistant transcript mRNA increased significantly under drought (DR) treatment, resulting in enhanced mRNA stability, which is involved in regulating sugarcane drought resistance. GO and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results showed that differentially methylated peak (DMP) modification of differentially expressed genes (DEGs) in DR were particularly associated with abscisic acid (ABA) biosynthesis. The upregulated genes were significantly enriched in the ABA metabolism, ethylene response, fatty acid metabolism, and negative regulation of the abscisic acid activation signaling pathway. These findings provide a basis and resource for sugarcane RNA epigenetic studies and further increase our knowledge of the functions of m⁶A modifications in RNA under abiotic stress.

Sugarcane is highly sensitive to the variations in soil moisture content capacity, and upregulated water stress efficiency restricts its development and crop output. Rhizospheric microbes and metabolites play key roles to mitigate the adverse effects of abiotic stresses, i.e., drought stress. The drought-tolerant wild sugarcane relative, Saccharum arundinaceum Retz., remains poorly characterized with respect to its rhizosphere microbial community dynamics under water limitation. To address this, we analyzed drought-associated shifts in the rhizosphere microbiome and metabolome by comparing native plants from a long-term arid habitat in Guangxi, China, with plants from an irrigated cultivation environment. We analyzed the effects of agronomic traits, soil properties, enzyme activities, and 16S rRNA sequencing and untargeted metabolomics to characterize microbial communities and metabolites, with correlation analyses. Results demonstrated that wild plants possessed thicker stems, higher proline levels, and increased antioxidant enzyme activity. Their rhizospheres were enriched with Actinobacteria, Proteobacteria, and Chloroflexi, which exhibited upregulated urease and acid phosphatase activities. Metabolites linked to phosphotransferase systems and sugar metabolisms were also more abundant. Positive correlations between these microbes, metabolites, and drought traits reveal site-specific microbial–metabolic modules that confer drought resilience, providing valuable insights for sugarcane breeding programs.

Drought stress substantially impairs citrus growth and alters the rhizosphere microbial composition; however, the role of these microbial communities in plant drought tolerance remains poorly understood. This study investigated the rhizosphere microbial structure, soil enzymatic activities, and physicochemical properties of drought-tolerant (DR) and drought-sensitive (DS) citrus varieties under drought stress conditions. High-throughput sequencing revealed that drought significantly altered microbial community composition, reducing the bacterial Shannon diversity by about 15% and enriching Gram-negative, stress-tolerant, and potentially pathogenic bacteria, as well as plant pathogenic fungi (upregulated 25.4% in DS), while reducing undefined saprotrophs (downregulated from 76.2 to 54.0% in DS). Notably, the DR variety exhibited a more stable and complex bacterial network, with 23.5% more edges and a higher proportion of positive correlations (54.3%), higher enrichment of beneficial fungi like Penicillium and Trichoderma, and unique recruitment of mycorrhizal fungi (up to 10.2%), which were nearly absent in DS. Furthermore, soil catalase and urease activities decreased under drought stress conditions. In contrast, acid phosphatase activity increased by up to 40% in DR. Correlation analyses indicated that these microbial shifts were closely associated with changes in soil nutrient availability. Our findings demonstrated that the drought-tolerant citrus variety modulates its rhizosphere microbiome towards a more cooperative and resilient state, highlighting the critical role of host-specific microbial recruitment in enhancing plant adaptation to drought stress for sustainable agriculture.

Sugarcane is an important crop across the globe, and the rapid multiplication of excellent cultivars is an important object of the sugarcane industry. As one of the plant growth regulators, paclobutrazol (PBZ) has been frequently used in the tissue culture of sugarcane seedlings. However, little is known about the molecular mechanisms of response to PBZ in this crop. Here, we performed a comparative transcriptome analysis between sensitive (LC05−136) and non−sensitive (GGZ001) sugarcane cultivars treated by PBZ at three time points (0 d, 10 d, and 30 d) using RNA sequencing (RNA−Seq). The results showed that approximately 70.36 Mb of clean data for each sample were generated and assembled into 239,212 unigenes. A total of 6108 and 4404 differentially expressed genes (DEGs) were identified within the sensitive and non−sensitive sugarcane cultivars, respectively. Among them, DEGs in LC05−136 were most significantly enriched in the photosynthesis and valine, leucine and isoleucine degradation pathways, while in GGZ001, DEGs associated with ion channels and plant–pathogen interaction were mainly observed. Notably, many interesting genes, including those encoding putative regulators, key components of photosynthesis, amino acids degradation and glutamatergic synapse, were identified, revealing their importance in the response of sugarcane to PBZ. Furthermore, the expressions of sixteen selected DEGs were tested by quantitative reverse transcription PCR (RT−qPCR), confirming the reliability of the RNA−seq data used in this study. These results provide valuable information regarding the transcriptome changes in sugarcane treated by PBZ and provide an insight into understanding the molecular mechanisms underlying the resistance to PBZ in sugarcane.

Sugarcane production in China is severely constrained by frequent seasonal droughts, especially in the major planting region of Guangxi. Identifying drought-resistant varieties is crucial for ensuring yield stability. This study aimed to comprehensively evaluate the drought resistance of 15 sugarcane varieties and screen key identification indicators. A pot experiment was conducted with both well-watered (control) and drought-stress treatments. Fifteen agronomic and physiological traits were measured, and drought resistance was assessed using the comprehensive drought resistance evaluation value (D value), the comprehensive drought resistance coefficient (CDC), and the weighted drought resistance coefficient (WDC). Results showed significant variations in trait responses to drought: green leaf number (NGL) decreased the most (66.06%), while proline (Pro) increased the most (88.09%). PCA reduced 15 traits to 5 principal components, with a cumulative variance contribution rate of 82.26%. Comprehensive evaluation using D values, comprehensive drought resistance coefficients (CDCs), and weighted drought resistance coefficients (WDCs) showed consistent overall drought resistance rankings, with slight differences in individual varieties. Cluster analysis based on D values classified the 15 varieties into three groups: 10 drought-resistant (66.67%, e.g., YZ08-1609, LT5), 3 moderately drought-resistant (e.g., GT08-56), and 2 drought-sensitive (GT10-612, ZT13-012). Grey relational analysis identified single stalk weight (SSW), number of leaves (NL), and number of green leaves (NGL) as key indicators closely associated with drought resistance. This study provides a scientific basis for establishing a drought-resistant sugarcane variety evaluation system and lays the foundation for breeding drought-resistant varieties.