Smut disease is caused by Sporisorium scitamineum, an important sugarcane fungal pathogen causing an extensive loss in yield and sugar quality. The available literature suggests that there are two types of smut resistance mechanisms: external resistance by physical or chemical barriers and intrinsic internal resistance mechanisms operating at host–pathogen interaction at cellular and molecular levels. The nature of smut resistance mechanisms, however, remains largely unknown. The present study investigated the changes in proteome occurring in two sugarcane varieties with contrasting susceptibility to smut—F134 and NCo310—at whip development stage after S. scitamineum infection. Total proteins from pathogen inoculated and uninoculated (control) leaves were separated by two-dimensional gel electrophoresis (2D-PAGE). Protein identification was performed using BLASTp and tBLASTn against NCBI nonredundant protein databases and EST databases, respectively. A total of thirty proteins spots representing differentially expressed proteins (DEPs), 16 from F134 and 14 from NCo310, were identified and analyzed by MALDI-TOF/TOF MS. In F134, 4 DEPs were upregulated and nine were downregulated, while, nine were upregulated and three were downregulated in NCo310. The DEPs were associated with DNA binding, metabolic processes, defense, stress response, photorespiration, protein refolding, chloroplast, nucleus and plasma membrane. Finally, the expression of CAT, SOD, and PAL with recognized roles in S. scitamineum infection in both sugarcane verities were analyzed by real-time quantitative PCR (RT-qPCR) technique. Identification of genes critical for smut resistance in sugarcane will increase our knowledge of S. scitamineum-sugarcane interaction and help to develop molecular and conventional breeding strategies for variety improvement.

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.

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.

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.

Narenga porphyrocoma (Hance) Bor is a close relative of sugarcane, with traits such as drought resistance, robustness, early maturity, and disease resistance. In this study, we report the first genome assembly of N. porphyrocoma (Hance) Bor GXN1, a diploid species with a chromosomal count of 2n = 30. We assembled the genome into 15 pseudochromosomes with an N50 of 128.80 Mp, achieving a high level of completeness (99.0%) using benchmarking universal single-copy orthologs (BUSCO) assessment. The genome was approximately 1.8 Gb. Our analysis identified a substantial proportion of repetitive sequences, primarily long terminal repeats (LTRs), contributing to 69.12% of the genome. In total, 70,680 protein-coding genes were predicted and annotated, focusing on genes related to drought resistance. Transcriptome analysis under drought stress revealed the key gene families involved in plant physiological rhythms and hormone signal transduction, including aquaporins, late embryogenesis abundant proteins, and heat shock proteins. This research reveals the genome of the diploid wild sugarcane relative N. porphyrocoma (Hance) Bor, encouraging future studies on gene function, genome evolution, and genetic improvement of sugarcane.