Drought Tolerance In Sugarcane Research Articles

Determination of Morpho-Physiological Traits for Assessing Drought Tolerance in Sugarcane.

Drought is a significant constraint to sugarcane productivity. Therefore, understanding how different varieties of sugarcane respond to drought stress can facilitate breeding programs and set up criteria for selecting drought-tolerant varieties. In the present study, we examined eight morpho-physiological traits to distinguish 40 sugarcane genotypes categorized into four groups based on significant differences in cane yield under non-stressed conditions and reduction of cane yield under drought-stressed conditions. The study was conducted during the formative stage in a greenhouse, encompassing both control and drought conditions. Drought treatments resulted in significant changes and differences in the mean values of various morpho-physiological traits. The hierarchical clustering analysis, utilizing stay-green traits such as higher chlorophyll fluorescence ratio (Fv/Fm), leaf chlorophyll content (SPAD), leaf relative water content (RWC), and lower leaf rolling score (LR), leaf drying score (LD), and drought recovery score (DR), successfully grouped 40 sugarcane genotypes into four major clusters, similar to the previously categorized groups. Correlation analysis showed significant relationships among cane yield, reduction of cane yield under drought conditions, and the stay-green traits. Our results demonstrated that morpho-physiological traits contributing to the "stay-green" phenotypes could be useful as selection criteria for drought tolerance in sugarcane.

Regulation of an endophytic nitrogen-fixing bacteria GXS16 promoting drought tolerance in sugarcane

BackgroundDrought limits crop growth and is an important issue in commercial sugarcane (Saccharum officinarum) production. Drought tolerance in sugarcane induced by endophytic nitrogen-fixing bacteria is a complex biological process that ranges from altered gene expression and cellular metabolism to changes in growth and productivity.ResultsIn this study, changes in physiological features and transcriptome related to drought tolerance in sugarcane conferred by the Burkholderia endophytic nitrogen-fixing bacterial strain GXS16 were investigated. Sugarcane samples inoculated with GXS16 exhibited significantly higher leaf relative water content than those without GXS16 inoculation during the drought stages. Sugarcane treated with GXS16 had lower levels of H2O2 and higher levels of abscisic acid than sugarcane not treated with GXS16 in the non-watering groups. Transcriptomic analysis of sugarcane roots identified multiple differentially expressed genes between adjacent stages under different treatments. Moreover, both trend and weighted correlation network analyses revealed that carotenoid biosynthesis, terpenoid backbone biosynthesis, starch and sucrose metabolism, and plant hormone signal transduction strongly contributed to the drought-tolerant phenotype of sugarcane induced by GXS16 treatment. Accordingly, a gene regulatory network including four differentially regulated genes from carotenoid biosynthesis (crtB, crtZ, ZEP and CYP707A) and three genes from terpenoid backbone biosynthesis (dxs, dxr, and PCME) was constructed.ConclusionsThis study provides insights into the molecular mechanisms underlying the application of GXS16 treatment to enhance drought tolerance in sugarcane, which will lay the foundation for crop development and improve productivity.

Overexpression of the Small Ubiquitin-Like Modifier protease OTS1 gene enhances drought tolerance in sugarcane (Saccharum spp. hybrid).

Sugarcane is an economically important crop plant across the globe as it is the primary source of sugar and biofuel. Its growth and development are greatly influenced by water availability; therefore, in periods of water scarcity, yields are severely compromised. Small Ubiquitin-Like Modifier (SUMO) proteases play an important role in stress responses by regulating the SUMO-related post-translational modification of proteins. In an attempt to enhance drought tolerance in sugarcane, this crop was genetically transformed with a cysteine protease (OVERLY TOLERANT TO SALT-1; OTS1) from Arabidopsis thaliana using particle bombardment. Transgenic plants were analysed in terms of photosynthetic capacity, oxidative damage, antioxidant accumulation and the SUMO-enrich protein profile was assessed. Sugarcane transformed with the AtOTS1 gene displayed enhanced drought tolerance and delayed leaf senescence under water deficit compared to the untransformed wild type (WT). The AtOTS1 transgenic plants maintained a high relative moisture content and higher photosynthesis rate when compared to the WT. In addition, when the transgene was expressed at high levels, the transformed plants were able to maintain higher stomatal conductance and chlorophyl content under moderate stress compared to the WT. Under severe water deficit stress, the transgenic plants accumulated less malondialdehyde and maintained membrane integrity. SUMOylation of total protein and protease activity was lower in the AtOTS1 transformed plants compared to the WT, with several SUMO-enriched proteins exclusively expressed in the transgenics when exposed to water deficit stress. SUMOylation of proteins likely influenced various mechanisms contributing to enhanced drought tolerance in sugarcane.

Diversity and Heterosis of Leaf Anatomical Traits in Backcross 1 (BC1) Derived from Interspecific Hybridization between Commercial Cane (Saccharum spp. Hybrid) and Wild Type (S. spontaneum)

Interspecific hybridization between commercial and wild canes followed by backcrossing may transfer favorable alleles responsible for drought tolerance in sugarcane. Our study aimed to assess the distribution of BC1 individuals on leaf anatomy and to classify them regarding heterosis values. Five BC1 populations were established using a commercial Saccharum spp. hybrid as a donor female and the F1 interspecific hybrids as recurrent males. Leaf anatomy included leaf thickness (LT), cuticle thickness (CT), the vertical length of bulliform cell (VBC), stomatal crypt depth (SCD), percent CT, percent VBC, and percent SCD. The anatomical traits of BC1 showed high phenotypic variations, and all populations can be divided into three groups based on their heterosis values. Heterosis seemed to be genotype and trait dependent as the estimates varied considerably across populations and observed traits, ranging from negative on LT to positive on VBC. Group I (BC1-1) showed positive heterosis on percent CT, percent VBC, and percent SCD. Dendrogram analysis revealed that some clones in population BC1-1 were promising regarding stalk weight and leaf anatomy, making them desirable for further clone selections. Backcrossing with commercial canes resulted in higher BC1 means than their mid-parents despite low heterosis on leaf anatomy.

A Large-Scale Candidate-Gene Association Mapping for Drought Tolerance and Agronomic Traits in Sugarcane.

Dissection of the genetic loci controlling drought tolerance traits with a complex genetic inheritance is important for drought-tolerant sugarcane improvement. In this study, we conducted a large-scale candidate gene association study of 649 candidate genes in a sugarcane diversity panel to identify genetic variants underlying agronomic traits and drought tolerance indices evaluated in plant cane and ratoon cane under water-stressed (WS) and non-stressed (NS) environments. We identified 197 significant marker-trait associations (MTAs) in 141 candidate genes associated with 18 evaluated traits with the Bonferroni correction threshold (α = 0.05). Out of the total, 95 MTAs in 78 candidate genes and 62 MTAs in 58 candidate genes were detected under NS and WS conditions, respectively. Most MTAs were found only in specific water regimes and crop seasons. These MTAs explained 7.93-30.52% of phenotypic variation. Association mapping results revealed that 34, 59, and 104 MTAs involved physiological and molecular adaptation, phytohormone metabolism, and drought-inducible genes. They identified 19 pleiotropic genes associated with more than one trait and many genes related to drought tolerance indices. The genetic and genomic resources identified in this study will enable the combining of yield-related traits and sugar-related traits with agronomic value to optimize the yield of sugarcane cultivars grown under drought-stressed and non-stressed environments.

Rapid identification of drought tolerant sugarcane epimutants via in vitro chimera dissolution and near infrared screening ex vitro

Drought is an important stress factor with increased severity due to climate change. Previous research characterised drought-tolerant sugarcane epimutants over several rounds of ex vitro screening on vegetatively derived survivors. In the present work, a quicker in vitro chimera dissolution over four stress rounds is reported in cultivar N41. Overall, epimutants were significantly taller (1.32–2.20 cm), had wider leaves (up to 0.40 cm) and thicker stems (0.26–0.37 cm) than the stressed control (S N41) with up to 0.92 cm height, 0.27 cm leaf width, and 0.18 cm stem diameter over the last three in vitro stress rounds. The Dry 8, Dry 5, Dry 2, Dry 3, and Dry 1 were identified as lines tolerant to osmotic and heat stress. When detached leaves were treated with polyethylene glycol for 7 days, Dry 8 and Dry 5 showed significantly higher green leaf areas of 90.02 and 80.29%, respectively, than S N41 with 60.23%. Following ex vitro drought selection, Dry 8 had a rapid growth rate (0.39 cm/day) compared with S N41 (0.23 cm/day). Based on near-infrared spectroscopy (NIRS) data, Dry 1, Dry 2, Dry 5, and Dry 8 were grouped with the non-stressed control (NS N41). The Dry 5 and Dry 8 epilines were persistently tolerant to osmotic, heat and drought stresses in pot-based bioassays and were identified as the best epilines in the study. These results suggest that stable epilines with drought tolerance potential can be obtained through in vitro screening methods and ex vitro NIR-based phenotyping, allowing a more rapid throughput of useful lines than in previous studies.

Comparative transcriptome profiling to unravel the key molecular signalling pathways and drought adaptive plasticity in shoot borne root system of sugarcane

Sugarcane root system comprises of superficial sett roots as well as deeply-penetrating shoot borne roots (SBR) with latter being the permanent root system. In sugarcane, the healthy SBR contributes to a better crop yield and it also helps to produce multiple ratoon crops after the harvest. There is a dearth of in-depth knowledge on SBR system architecture and its functional role in modern day commercial hybrids. A comprehensive phenotypic, anatomical and whole transcriptome profiling, conducted between the commercial sugarcane hybrids and a wild germplasm Erianthus, found a developmental delay in both initiation and establishment of the SBR in commercial hybrid compared to Erianthus. The SBR system in Erianthus proved to be an extensive drought-adaptive root system architecture that significantly contributes to drought tolerance. On the other hand, SBRs in the commercial hybrids showed an irreversible collapse and damage of the root cells under drought stress. The outcomes from the comparative analysis of the transcriptome data showed a significant upregulation of the genes that regulate important stress signalling pathways viz., sugar, calcium, hormone signalling and phenylpropanoid biosynthesis in the SBRs of Erianthus. It was found that through these key signalling pathways, Erianthus SBRs triggered the downstream signalling cascade to impart physiological responses like osmoprotection, modification of the cell walls, detoxification of reactive oxygen species, expression of drought responsive transcription factors, maintenance of cell stability and lateral root development. The current study forms a basis for further exploration of the Shoot Borne Root system as a valuable breeding target to develop drought tolerant sugarcane genotypes.

Ex vitro Morpho-Physiological Screening of Drought Tolerant Sugarcane Epimutants Generated Via 5-Azacytidine and Imidacloprid Treatments

Ex vitro Morpho-Physiological Screening of Drought Tolerant Sugarcane Epimutants Generated Via 5-Azacytidine and Imidacloprid Treatments

Integrated Analysis of Transcriptome and Metabolome Reveals the Regulation of Chitooligosaccharide on Drought Tolerance in Sugarcane (Saccharum spp. Hybrid) under Drought Stress.

Sugarcane (Saccharum spp. hybrid) is an important crop for sugar and biofuels, and often suffers from water shortages during growth. Currently, there is limited knowledge concerning the molecular mechanism involved in sugarcane response to drought stress (DS) and whether chitooligosaccharide could alleviate DS. Here, we carried out a combined transcriptome and metabolome of sugarcane in three different treatment groups: control group (CG), DS group, and DS + chitooligosaccharide group (COS). A total of 12,275 (6404 up-regulated and 5871 down-regulated) differentially expressed genes (DEGs) were identified when comparing the CG and DS transcriptomes (T_CG/DS), and 2525 (1261 up-regulated and 1264 down-regulated) DEGs were identified in comparing the DS and COS transcriptomes (T_DS/COS). GO and KEGG analysis showed that DEGs associated with photosynthesis were significantly enriched and had down-regulated expression. For T_DS/COS, photosynthesis DEGs were also significantly enriched but had up-regulated expression. Together, these results indicate that DS of sugarcane has a significantly negative influence on photosynthesis, and that COS can alleviate these negative effects. In metabolome analysis, lipids, others, amino acids and derivatives and alkaloids were the main significantly different metabolites (SDMs) observed in sugarcane response to DS, and COS treatment reduced the content of these metabolites. KEGG analysis of the metabolome showed that 2-oxocarboxylic acid metabolism, ABC transporters, biosynthesis of amino acids, glucosinolate biosynthesis and valine, leucine and isoleucine biosynthesis were the top-5 KEGG enriched pathways when comparing the CG and DS metabolome (M_CG/DS). Comparing DS with COS (M_DS/COS) showed that purine metabolism and phenylalanine metabolism were enriched. Combined transcriptome and metabolome analysis revealed that pyruvate and phenylalanine metabolism were KEGG-enriched pathways for CG/DS and DS/COS, respectively. For pyruvate metabolism, 87 DEGs (47 up-regulated and 40 down-regulated) and five SDMs (1 up-regulated and 4 down-regulated) were enriched. Pyruvate was closely related with 14 DEGs (|r| > 0.99) after Pearson’s correlation analysis, and only 1 DEG (Sspon.02G0043670-1B) was positively correlated. For phenylalanine metabolism, 13 DEGs (7 up-regulated and 6 down-regulated) and 6 SDMs (1 up-regulated and 5 down-regulated) were identified. Five PAL genes were closely related with 6 SDMs through Pearson’s correlation analysis, and the novel.31257 gene had significantly up-regulated expression. Collectively, our results showed that DS has significant adverse effects on the physiology, transcriptome, and metabolome of sugarcane, particularly genes involved in photosynthesis. We further show that COS treatment can alleviate these negative effects.

Drought Stress in Sugarcane: In-vitro Mutagenesis and Selection of Polyethylene Glycol (PEG) Tolerant Callus Lines

Drought is one of the key abiotic factors causing a loss in sugarcane output, which is one of the world's thirstiest crops. A mutant sugarcane callus line was used to create an in vitro selection system for drought resistance. The objective of this study was to obtain putative sugarcane mutant callus lines that had been chemically altered with sodium azide at various concentrations (0, 0.5, 1.0, and 1.5%). These lines were subsequently screened using high molecular weight PEG 6000 as a selection agent at various concentrations (0, 5, 10, 15, 20, 25, and 30%). The experiment demonstrated a decline in the proportion of live callus and sensitivity index with increasing mutation concentration and PEG dose, with little to no live callus at the maximum mutation and PEG concentration. Biochemical investigation of the survived callus for proline accumulation and salicylic acid content revealed an elevated level of up to 20 percent PEG and 1.0 percent mutagen, followed by a quick drop as PEG and mutagen concentrations increased. The findings can be used to create drought-tolerant sugarcane lines and putative mutants, as well as to screen them in vitro.

Leaf transcriptome profiling of contrasting sugarcane genotypes for drought tolerance under field conditions

Drought is the most detrimental abiotic stress to sugarcane production. Nevertheless, transcriptomic analyses remain scarce for field-grown plants. Here we performed comparative transcriptional profiling of two contrasting sugarcane genotypes, ‘IACSP97-7065’ (drought-sensitive) and ‘IACSP94-2094’ (drought-tolerant) grown in a drought-prone environment. Physiological parameters and expression profiles were analyzed at 42 (May) and 117 (August) days after the last rainfall. The first sampling was done under mild drought (soil water potential of −60 kPa), while the second one was under severe drought (soil water potential of −75 kPa). Microarray analysis revealed a total of 622 differentially expressed genes in both sugarcane genotypes under mild and severe drought stress, uncovering about 250 exclusive transcripts to ‘IACSP94-2094’ involved in oxidoreductase activity, transcriptional regulation, metabolism of amino acids, and translation. Interestingly, the enhanced antioxidant system of ‘IACSP94-2094’ may protect photosystem II from oxidative damage, which partially ensures stable photochemical activity even after 117 days of water shortage. Moreover, the tolerant genotype shows a more extensive set of responsive transcription factors, promoting the fine-tuning of drought-related molecular pathways. These results help elucidate the intrinsic molecular mechanisms of a drought-tolerant sugarcane genotype to cope with ever-changing environments, including prolonged water deficit, and may be useful for plant breeding programs.

Breeding for Drought Tolerance in Sugarcane: Indian Perspective

Breeding for Drought Tolerance in Sugarcane: Indian Perspective

Gene Co-Expression Analysis Reveals Transcriptome Divergence between Wild and Cultivated Sugarcane under Drought Stress.

Drought is the main abiotic stress that constrains sugarcane growth and production. To understand the molecular mechanisms that govern drought stress, we performed a comprehensive comparative analysis of physiological changes and transcriptome dynamics related to drought stress of highly drought-resistant (ROC22, cultivated genotype) and weakly drought-resistant (Badila, wild genotype) sugarcane, in a time-course experiment (0 h, 4 h, 8 h, 16 h and 32 h). Physiological examination reviewed that ROC22, which shows superior drought tolerance relative to Badila, has high performance photosynthesis and better anti-oxidation defenses under drought conditions. The time series dataset enabled the identification of important hubs and connections of gene expression networks. We identified 36,956 differentially expressed genes (DEGs) in response to drought stress. Of these, 15,871 DEGs were shared by the two genotypes, and 16,662 and 4423 DEGs were unique to ROC22 and Badila, respectively. Abscisic acid (ABA)-activated signaling pathway, response to water deprivation, response to salt stress and photosynthesis-related processes showed significant enrichment in the two genotypes under drought stress. At 4 h of drought stress, ROC22 had earlier stress signal transduction and specific up-regulation of the processes response to ABA, L-proline biosynthesis and MAPK signaling pathway–plant than Badila. WGCNA analysis used to compile a gene regulatory network for ROC22 and Badila leaves exposed to drought stress revealed important candidate genes, including several classical transcription factors: NAC87, JAMYB, bHLH84, NAC21/22, HOX24 and MYB102, which are related to some antioxidants and trehalose, and other genes. These results provide new insights and resources for future research and cultivation of drought-tolerant sugarcane varieties.

Field evaluation of the potential of drought-tolerant sugarcane (Saccharum officinarum L.) mutants based on morpho-agronomic characters

A mutation scheme followed by an in-vitro selection is one of the breeding tools for developing drought-tolerant sugarcane varieties. This study aimed to select the drought-tolerant sugarcane mutants. Twenty-seven mutant genotypes that passed the in-vitro selection for drought-tolerant and a Bululawang variety as control were examined in this study. The field evaluation was done in Asembagus, Situbondo, East Java, from January 2019 to December 2020. The four-month-old plants were exposed to drought conditions for two months period. The experiment used a Randomized Complete Block Design with three replications. The observations were made on morpho-agronomic parameters such as a leaf, leaf sheath, internode, stem, bud characters, stem length, diameter, stem weight, internode’s number and length, yield, and Brix. Results showed that three mutant genotypes performed better under simulated drought stress than the BL variety with higher yield potential (> 125 ton ha−1). These mutants differed from their original cultivar in the leaf sheath, internode, stem, and bud, hairy, and adherence-leaf sheath characters. Shortly, further evaluation of agronomical performances will be made on the first and second ratoon.

Leaf Anatomical Adaptation Under Early Drought Stress of Sugarcane Cultivars – KKU-1999-02 and KKU-1999-03

Abstract Anatomical adaptation is an important feature that allows plants to mitigate drought stress. A comparative leaf anatomy of two drought-tolerant sugarcane cultivars, KKU-1999-02 and KKU-1999-03, was studied in early drought stress between 30 and 90 days after planting using peeling and freehand sectioning methods. KKU-1999-02 and KKU-1999-03 showed different anatomical adaptation features, such as increase in cuticle thickness, bulliform cell size, vascular bundle, and stomatal density, and decreases in leaf thickness and stomatal size. KKU-1999-02 showed more remarkable anatomical changes than KKU-1999-03. The results provide important information that can be applied in combination with other agronomic traits in sugarcane breeding programs to expand the adaptation devices of tolerant cultivars under preliminary drought stress.

Understanding Growth Rate Patterns among Different Drought Resistant Sugarcane Cultivars during Plant and Ratoon Crops Encountered Water Deficit at Early Growth Stage under Natural Field Conditions

Drought-tolerant sugarcane genotypes have been proposed to alleviate the issue of early water deficits; however, it is important to investigate the impact of phenology on the crop growth rate and growth patterns. This study aimed to investigate the responses of different water deficit-tolerant cultivars on crop growth rate patterns of both plant crop and ratoon under rain-fed and well-irrigated conditions, and to determine the relationship between final stalk dry weight and crop growth rates during water deficit, recovery, and maturity phases. A 2 × 6 split plot in a randomized complete block design with four replications was used. Two water regimes, namely, field capacity (FC) and rain-fed conditions, were assigned as the main plot, whereas six sugarcane cultivars differing in water deficit-tolerant levels were assigned as sub-plots. Sugarcane cultivar KK3 consistently possessed high potential and low reduction in dried shoot weight. A correlation was found between stalk dry weight and stem growth rate, shoot growth rate, and height growth rate (HGR) during the recovery period in the first season, and HGR at the recovery stage was correlated with the dry weight of ratoon. The recovery phase of early water deficit stress was a key stage for determining the final stalk dry matter. The desired cultivars having a good adaptation to water deficit stress at the formative stage, such as KK3, showed a gradually increased growth rate during the early water deficit stage, but this growth accelerated, and the maximum growth rate was reached, during the recovery period. This knowledge will help to clarify the selection of sugarcane cultivars in breeding programs that can resist water deficit at the early growth stage.

Silicon fertilization increases gas-exchange and biomass by silicophytolith deposition in the leaves of contrasting drought-tolerant sugarcane cultivars under well-watered conditions

PurposeSilicon (Si) fertilization provides benefits to sugarcane. However, information remain scarce about the relationship between Si fertilization, gas exchange responses, biomass and silicophytolith accumulation in contrasting drought tolerant sugarcane cultivars under well-watered conditionsMethodsSugarcane cultivars (drought-tolerant and drought-sensitive) were grown in pots containing soil with low available Si and were treated (at rates equivalent to 0, 250, 500, 750, and 1000 kg ha−1 Si) with Si as silicate. The silicophytolith contents, morphotype descriptions, Si concentrations and gas exchange were evaluated in the top visible dewlap leaves. Stalk length and stalk biomass were also evaluated.ResultsThe silicophytolith, Si contents, net CO2 assimilation rate (A), plant transpiration (E), stomatal conductance (gs) and electron transport rate (ETR) of leaves and fresh biomass and length of stalks increased linearly as functions of the Si application rate, independent of cultivar. RB86-7515 showed the highest stalk length, fresh stalk and green leaf biomass, relative water content, and water potential, while RB85-5536 showed superior values for A, E, gs, and ETR.ConclusionsSi fertilization improved photosynthesis, transpiration, stalk length, and stalk biomass production in sugarcane. The highest silicophytolith content was reflected in a diversity of silicified cells, which may favor a higher photosynthesis and biomass. The increase of silicification in stomata complexes and trichomes with Si may be associated to a higher Si availability and transpiration. Contrasting drought-tolerant cultivars showed similar silicification and gas exchange responses with Si. Considering these benefits, Si should be included in the fertilization program of sugarcane.

High-throughput miRNA deep sequencing in response to drought stress in sugarcane.

The online version contains supplementary material available at 10.1007/s13205-021-02857-x.

In Vitro Screening of Sugarcane Cultivars (Saccharum spp. Hybrids) for Tolerance to Polyethylene Glycol-Induced Water Stress

Water stress caused by drought affects the productivity of the sugarcane crop. A breeding alternative is the selection of drought-tolerant sugarcane cultivars. The objective of this study was the in vitro screening of cultivars tolerant to water stress using polyethylene glycol (PEG) as a stressing agent. Cultivars (cv) Mex 69-290, CP 72-2086, Mex 79-431 and MOTZMex 92-207 were subjected to different concentrations of PEG 6000 (0, 3, 6 and 9% w/v) using Murashige and Skoog semi-solid culture medium. At 30 days of culture, different developmental variables and dry matter (DM), total protein (TP), proline (Pr) and glycine-betaine (GB) contents were evaluated. The results showed reduced development in cv CP 72-2086, Mex 79-431 and MOTZMex 92-207 with increasing PEG concentration. The cv Mex 69-290 showed tolerance to osmotic stress of −0.45 MPa using 3% PEG. Overall, TP content decreased with increasing PEG concentration, while DM, Pr and GB contents rose with increasing PEG concentration in all evaluated cultivars. Our results suggest that cv Mex 69-290 has a slight tolerance to water stress and could be used for rainfed cultivation with low rainfall or reduced irrigation for better water use efficiency. In conclusion, the in vitro screening technique of cultivars tolerant to PEG-induced water stress is an alternative for early determination of drought stress in sugarcane.

Physiological changes and transcriptome profiling in Saccharum spontaneum L. leaf under water stress and re-watering conditions

As the polyploidy progenitor of modern sugarcane, Saccharum spontaneum is considered to be a valuable resistance source to various biotic and abiotic stresses. However, little has been reported on the mechanism of drought tolerance in S. spontaneum. Herein, the physiological changes of S. spontaneum GXS87-16 at three water-deficit levels (mild, moderate, and severe) and after re-watering during the elongation stage were investigated. RNA sequencing was utilized for global transcriptome profiling of GXS87-16 under severe drought and re-watered conditions. There were significant alterations in the physiological parameters of GXS87-16 in response to drought stress and then recovered differently after re-watering. A total of 1569 differentially expressed genes (DEGs) associated with water stress and re-watering were identified. Notably, the majority of the DEGs were induced by stress. GO functional annotations and KEGG pathway analysis assigned the DEGs to 47 GO categories and 93 pathway categories. The pathway categories were involved in various processes, such as RNA transport, mRNA surveillance, plant hormone signal transduction, and plant-pathogen interaction. The reliability of the RNA-seq results was confirmed by qRT-PCR. This study shed light on the regulatory processes of drought tolerance in S. spontaneum and identifies useful genes for genetic improvement of drought tolerance in sugarcane.