Sugarcane, a vital cash crop, contributes significantly to the world’s sugar supply and raw materials for biofuel production, playing a significant role in the global sugar industry. However, sustainable productivity is severely hampered by biotic and abiotic stressors. Genetic engineering has been used to transfer useful genes into sugarcane plants to improve desirable traits and has emerged as a basic and applied research method to maintain growth and productivity under different adverse environmental conditions. However, the use of transgenic approaches remains contentious and requires rigorous experimental methods to address biosafety challenges. Clustered regularly interspaced short palindromic repeat (CRISPR) mediated genome editing technology is growing rapidly and may revolutionize sugarcane production. This review aims to explore innovative genetic engineering techniques and their successful application in developing sugarcane cultivars with enhanced resistance to biotic and abiotic stresses to produce superior sugarcane cultivars.

Background: The MAP Kinase cascade system is a conserved signaling mechanism essential for plant development, growth, and stress tolerance. Thus far, genes from the MAPK cascade have been identified in several plant species but remain uncharacterized in the polyploid Saccharum spp. Hybrid R570 genome. Results: This study identified 89 ScMAPK, 24 ScMAPKK, and 107 ScMAPKKK genes through genome-wide analysis. Phylogenetic classification revealed that four subgroups were present in each ScMAPK and ScMAPKK family, and three sub-families (ZIK-like, RAF-like, and MEKK-like) presented in the ScMAPKKK family. Conserved motif and gene structure analysis supported the evolutionary relationships of the three families inferred from the phylogenetic analysis. All of the ScMAPK, ScMAPKK and ScMAPKKK genes were mapped on four scaffolds (Scaffold_88/89/91/92) and nine chromosomes (1–8, 10). Collinearity and gene duplication analysis identified 169 pairs of allelic and non-allelic segmentally duplicated MAPK cascade genes, contributing to their expansion. Additionally, 13 putative ‘ss-miRNAs’ were predicted to target 87 MAPK cascade genes, with ‘ssp-miR168a’ alone regulating 45 genes. qRT-PCR analysis revealed differential gene expression under abiotic stressors. ScMAPK07, ScMAPK66, and ScRAF43 were down-regulated and acted as negative regulators. Conversely, ScMAPKK13, ScRAF10, and ScZIK18 were up-regulated at specific time points under drought, with ScZIK18 exhibiting strong defense. Under NaCl stress, most genes were down-regulated, except for slight increases in ScZIK18 and ScMAPKK13, suggesting a positive role in salt stress response. Under CaCl₂ stress, five genes were significantly down-regulated, while ScRAF43 remained unchanged, reflecting their negative roles in stress adaptation and resource conservation. Conclusion: This study provides insights into MAPK cascade gene evolution and function in sugarcane, highlighting distinct regulatory roles in abiotic stress responses. Interestingly, some genes acted as negative regulators, serving as a mechanism to balance stress responses and prevent overactivation. In contrast, others contributed to defense mechanisms, offering potential targets for stress resilience improvement. Clinical Trail Number: This study contains no clinical trials. Not applicable.

This study aimed to prepare the sugar industry for the possible introduction of genetically modified (GM) sugarcane and derived retail sugar products and to address several potential public concerns regarding the characteristics and safety of these products. GM sugarcane lines with integrated Cry1Ab and EPSPS foreign genes were used for GM sugar production. Traditional PCR, real-time fluorescent quantitative PCR (RT-qPCR), and enzyme-linked immunosorbent assay (ELISA) were performed in analyzing leaves, stems, and other derived materials during sugar production, such as fibers, clarified juices, filter mud, syrups, molasses, and final GM sugar product. The toxicity of GM sugar was examined with a feeding bioassay using Helicoverpa armigera larvae. PCR and RT-qPCR results showed that the leaves, stems, fibers, juices, syrups, filter mud, molasses, and white granulated sugar from GM sugarcane can be distinguished from those derived from non-GM sugarcane. The RT-qPCR detection method using short amplified product primers was more accurate than the traditional PCR method. Molecular analysis results indicated that trace amounts of DNA residues remain in GM sugar, and thus it can be accurately characterized using molecular analysis methods. ELISA results showed that only the leaves, stems, fibers, and juices sampled from the GM sugarcane differed from those derived from the non-GM sugarcane, indicating that filter mud, syrup, molasses, and white sugar did not contain detectable Cry1Ab and EPSPS proteins. Toxicity analysis showed that the GM sugar was not toxic to the H. armigera larvae. The final results showed that the GM sugar had no active proteins despite containing trace amounts of DNA residues. This finding will help to pave the way for the commercialization of GM sugarcane and production of GM sugar.

GRAS gene family plays multifunctional roles in plant growth, development, and resistance to various biotic and abiotic stresses, belonging to the plant-specific transcription factor (TF) family. In this study, a genome-wide survey and systematic analysis of the GRAS family in cultivated hybrid sugarcane ZZ1 (Saccharum officinarum) with economic and industrial importance was carried out. We identified 747 GRAS genes with complete structural domains and classified these into 11 subfamilies by phylogenetic analyses, exhibiting a diverse range of molecular weight and isoelectric points, thereby indicating a broad structural and functional spectrum. Analysis of Protein motif and gene structure revealed a conserved yet variable arrangement of motifs within the GRAS TFs, suggesting its potential for diverse functional roles. Furthermore, the identification of numerous cis-regulatory elements by GRAS TFs promoter sequence analysis, implying their complex regulation in response to environmental and physiological signals. Tertiary structure predictions analyses using AlphaFold3 highlighted the structural flexibility and conservation within the GRAS family, with disordered regions potentially contributing to their functional versatility. Weighted Gene Co-expression Network Analysis (WGCNA) provided insights into the potential roles of ShGRAS21A in sugarcane’s response to smut infection. This comprehensive investigation of the GRAS family in ZZ1 not only uncovers their structural diversity but also sheds light on their potential regulatory roles in plant growth, development, and stress response. The findings contribute to a deeper understanding of GRAS TFs functions and lay the groundwork for future studies on their role in sugarcane improvement and disease resistance.

The improvement of sucrose yield in sugarcane is impeded by the crop’s complex polyploid genome and slow progress in breeding. To clarify how arginine (Arg) regulates sugar metabolism and identify key genes associated with sucrose transport and accumulation in sugarcane, a screening experiment was performed by spraying L-arginine hydrochloride on the leaves and leaf sheaths of three sugarcane varieties (YZ05-51, YZ08-1609, and YT93-159), which differ in growth vigor, leaf morphology and other phenotypic traits. YZ05-51 exhibited the most prominent sugar-increasing effect, and subsequent optimization experiments on its leaf sheaths revealed that 20 g/mu L-arginine hydrochloride at pH 7.0 was optimal, significantly enhancing stem sucrose content. Transcriptomic analysis revealed the upregulation of genes related to sucrose synthesis and transport, with candidate genes enriched in pathways such as starch-sucrose metabolism, glycolysis/gluconeogenesis, and ATP-binding cassette (ABC) transporters. Metabolomic analysis detected 32 sugar metabolites across three categories, of which 24 were differentially abundant (e.g., glucose, galactose, fructose, and mannose). Integrated multi-omics analysis identified key regulatory genes, including SBEs and TPS1 (sucrose synthesis and carbon flux regulation), RBSK, α-amylases, GH28 (starch breakdown, glycolysis, and sugar mobilization), ABC transporters, GTs, and TIM10/TIM12 (sucrose transporter). Collectively, these analyses demonstrate enhanced activity of genes and metabolites involved in sucrose synthesis/transport in leaf sheaths, accompanied by reduced synthesis of other monosaccharides and oligosaccharides. Vigorously metabolizing leaf sheaths is more conducive to sucrose transport. This study provides valuable insights into the molecular mechanisms underlying Arg-mediated sucrose accumulation specifically in the sugarcane YZ05-51 sugarcane, highlighting its critical regulatory roles.

Plants significantly shape root-associated microbiota, making rhizosphere microbes useful environmental indicator organisms for safety assessment. Here, we report the pyrosequencing of the bacterial 16S ribosomal RNA in rhizosphere soil samples collected from transgenic cry1Ab/cry1Ac Bt rice Huahui No. 1 (GM crop) and its parental counterpart, Minghui63. We identified a total of 2579 quantifiable bacterial operational taxonomic units (OTUs). Many treatment-enriched microbial OTUs were identified, including 14 NonGM-enriched OTUs and 10 GM-enriched OTUs. OTUs belonging to the phyla Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes, Nitrospirae, Chlorobi and GN04 were identified as statistically different in abundance between GM and the other two treatments. Compared with the different impacts of different rice varieties on microbiota, the impact of rice planting on microbiota is more obvious. Furthermore, Huahui No. 1 transgenic Bt rice had a greater impact on the rhizosphere bacterial communities than Minghui63. Early developmental stages of the transgenic Bt rice had a significant impact on many Bacillaceae communities. Soil chemical properties were not significantly altered by the presence of transgenic Bt rice. The peak concentration level of Bt protein products was detected during the seedling stage of transgenic Bt rice, which may be an intriguing factor for bacterial diversity variations. Based on these findings, we conclude that transgenic Bt rice has a significant impact on root-associated bacteria. This information may be leveraged in future environmental safety assessments of transgenic Bt rice varieties.