Enhanced sugar accumulation and regulated plant hormone signalling genes contribute to cold tolerance in hypoploid Saccharum spontaneum

Overexpression of VaBAM3 from Vitis amurensis enhances seedling cold tolerance by promoting soluble sugar accumulation and reactive oxygen scavenging

KEY MESSAGE

The VaBAM3 cloned from Vitis amurensis can enhance the cold tolerance of overexpressed plants, but VaBAM3 knock out by CRISPR/Cas9 system weakened grape callus cold tolerance. In grape production, extreme cold conditions can seriously threaten plant survival and fruit quality. Regulation of starch content by β-amylase (BAM, EC: 3.2.1.2) contributes to cold tolerance in plants. In this study, we cloned the VaBAM3 gene from an extremely cold-tolerant grape, Vitis amurensis, and overexpressed it in tomato and Arabidopsis plants, as well as in grape callus for functional characterization. After exposure to cold stress, leaf wilting in the VaBAM3-overexpressing tomato plants was slightly less pronounced than that in wild-type tomato plants, and these plants were characterized by a significant accumulation of autophagosomes. Additionally, the VaBAM3-overexpressing Arabidopsis plants had a higher freezing tolerance than the wild-type counterparts. Under cold stress conditions, the activities of total amylase, BAM, peroxidase, superoxide dismutase, and catalase in VaBAM3-overexpressing plants were significantly higher than those in the corresponding wild-type plants. Furthermore, sucrose, glucose, and fructose contents in these lines were similarly significantly higher, whereas starch contents were reduced in comparison to the levels in the wild-type plants. Furthermore, we detected high CBF and COR gene expression levels in cold-stressed VaBAM3-overexpressing plants. Compared with those in VaBAM3-overexpressing grape callus, the aforementioned indicators tended to change in the opposite direction in grape callus with silenced VaBAM3. Collectively, our findings indicate that heterologous overexpression of VaBAM3 enhanced cold tolerance of plants by promoting the accumulation of soluble sugars and scavenging of excessive reactive oxygen species. These findings provide a theoretical basis for the cultivation of cold-resistant grape and support creation of germplasm resources for this purpose.

Genome-wide identification of RNA recognition motif (RRM1) in Brassica rapa and functional analysis of RNA-binding protein (BrRBP) under low-temperature stress

BACKGROUND

The RNA recognition motif (RRM) is primarily engaged in the processing of mRNA and rRNA following gene transcription as well as the regulation of RNA transport; it is critical in preserving RNA stability.

RESULTS

In this study, we identified 102 members of the RRM1 gene family in Brassica rapa, which were dispersed across 10 chromosomes with the ninth chromosome being the most extensively distributed. The RRM1 gene family members of Brassica rapa and Arabidopsis thaliana were grouped into 14 subclades (I-XIV) using phylogenetic analysis. Moreover, the results of transcriptome analysis and RT-qPCR indicated that the expression of Brapa05T000840 was upregulated in the cultivars 'Longyou 7' and 'Longyou 99' following exposure to cold stress at a temperature of 4 °C for 24 h. The levels of expression in the leaves and growth cones of the 'Longyou 7' variety were found to be significantly higher than those observed in the 'Longyou 99' variety under conditions of low temperature and NaCl stress. It illustrates the involvement of the RRM1 gene in the physiological response to both low temperature and salt stress. In addition, it was observed that the survival rate of transgenic BrRBP (Brapa05T000840) Arabidopsis thaliana plants was notably higher compared to that of wild-type plants when subjected to varying durations of low temperature treatment. Furthermore, the expression of the BrRBP gene in transgenic plants exhibited an upward trend as the duration of low temperature treatment increased, reaching its peak at 24 h. The in-vivo enzymatic activity of reactive oxygen species-scavenging enzymes were found to be significantly elevated in comparison to wild-type plants, suggesting that the BrRBP gene may enhance the cold tolerance of Arabidopsis thaliana.

CONCLUSIONS

This study offers a significant foundation for comprehending the regulation mechanism of the RRM1 gene family in winter Brassica rapa subjected to cold stress, as well as for finding key genes associated with cold resistance.

Heterologous Expression of OtsB Increases Tuber Yield and Phenotypic Stability in Potato under Both Abiotic and Biotic Stresses

Climate-smart and sustainable crops are needed for the future. Engineering crops for tolerance of both abiotic and biotic stress is one approach. The accumulation of trehalose, controlled through trehalose-6-phosphate synthase (TPS) or OtsA and trehalose-6-phosphate phosphatase (TPP) or OtsB genes in microbes, is known to provide protection for many microbial and fungal species against abiotic stress. The effect of trehalose accumulation in plant species is less understood. Here, we studied the heterologous expression of Escherichia coli OtsB in potato (Solanum tuberosum var. 'Desiree') with regards to stress tolerance. The performance of transgenic lines was assessed in both growth chambers and greenhouse mesocosms. Overexpressing potato OtsB lines significantly increased resilience to heat, photoperiod, herbivory, and competition when compared with wildtype plants. Most strikingly, when subjected to high temperatures, transgenic lines exhibited a significantly lower reduction in tuber yield ranging from 40% to 77%, while wildtype plants experienced a 95% decrease in tuber yield. When exposed to competitors in a selected StSP3D::OtsB line, tuber yield was 1.6 times higher than wildtype. Furthermore, transgenic lines performed significantly better under low-nutrient regimes: under competition, yield increased by 1.5-fold. Together, these results demonstrate that increased trehalose has the potential to create more resistant and stable crop plants.

Lemnaceae as Novel Crop Candidates for CO2 Sequestration and Additional Applications

Atmospheric carbon dioxide (CO2) is projected to be twice as high as the pre-industrial level by 2050. This review briefly highlights key responses of terrestrial plants to elevated CO2 and compares these with the responses of aquatic floating plants of the family Lemnaceae (duckweeds). Duckweeds are efficient at removing CO2 from the atmosphere, which we discuss in the context of their exceptionally high growth rates and capacity for starch storage in green tissue. In contrast to cultivation of terrestrial crops, duckweeds do not contribute to CO2 release from soils. We briefly review how this potential for contributions to stabilizing atmospheric CO2 levels is paired with multiple additional applications and services of duckweeds. These additional roles include wastewater phytoremediation, feedstock for biofuel production, and superior nutritional quality (for humans and livestock), while requiring minimal space and input of light and fertilizer. We, furthermore, elaborate on other environmental factors, such as nutrient availability, light supply, and the presence of a microbiome, that impact the response of duckweed to elevated CO2. Under a combination of elevated CO2 with low nutrient availability and moderate light supply, duckweeds' microbiome helps maintain CO2 sequestration and relative growth rate. When incident light intensity increases (in the presence of elevated CO2), the microbiome minimizes negative feedback on photosynthesis from increased sugar accumulation. In addition, duckweed shows a clear propensity for absorption of ammonium over nitrate, accepting ammonium from their endogenous N2-fixing Rhizobium symbionts, and production of large amounts of vegetative storage protein. Finally, cultivation of duckweed could be further optimized using hydroponic vertical farms where nutrients and water are recirculated, saving both resources, space, and energy to produce high-value products.

The SsWRKY1 transcription factor of Saccharum spontaneum enhances drought tolerance in transgenic Arabidopsis thaliana and interacts with 21 potential proteins to regulate drought tolerance in S. spontaneum

In this study, we characterized a WRKY family member gene, SsWRKY1, which is located in the nucleus and contains multiple stress-related cis-acting elements. In addition, constructed SsWRKY1-overexpressing Arabidopsis thaliana had higher antioxidant enzyme activity and proline content under drought stress conditions, with lower malondialdehyde content and reactive oxygen species (ROS) accumulation, and the expression levels of six stress-related genes were significantly upregulated. This indicates that the overexpression of SsWRKY1 in Arabidopsis thaliana improves resistance to drought stress. SsWRKY1 does not have transcriptional autoactivation activity in yeast cells. The yeast two-hybrid (Y2H) system and the S. spontaneum cDNA library were used to screen 21 potential proteins that interact with SsWRKY1, and the interaction between SsWRKY1 and ATAF2 was verified by GST pull-down assay. In summary, our results indicate that SsWRKY1 plays an important role in the response to drought stress and provide initial insights into the molecular mechanism of SsWRKY1 in response to drought stress.

Overexpression of major latex protein 423 (NtMLP423) enhances the chilling stress tolerance in Nicotiana tabacum

Chilling stress impedes plant growth and hinders crop development and productivity. In this study, we identified the major latex protein (MLP) in tobacco (NtMLP423) and examined its roles in chilling resistance. NtMLP423 expression was considerably upregulated in response to chilling stress. NtMLP423 function was assessed and compared in plants with overexpression and antisense characteristics. Under chilling stress, plants with overexpression characteristics grew better than wild-type and antisense plants. NtMLP423 overexpression reduced membrane lipid damage, increased antioxidant enzyme activity, and reduced reactive oxygen species (ROS) accumulation under chilling stress. Here, we screened for the first time the upstream transcription factor NtMYB108, which regulates NtMLP423 expression under chilling stress. The NtMYB108 transcription factor directly binds to the NtMLP423 promoter and improves NtMLP423 resistance to chilling stress. Subjecting NtMYB018 to virus-induced gene silencing reduced chilling stress tolerance. Overall, NtMLP423 overexpression enhances chilling stress tolerance, while its suppression has the opposite effect.

Tissue-Specific Transcriptome and Metabolome Analysis Reveals the Response Mechanism of Brassica napus to Waterlogging Stress

During the growth period of rapeseed, if there is continuous rainfall, it will easily lead to waterlogging stress, which will seriously affect the growth of rapeseed. Currently, the mechanisms of rapeseed resistance to waterlogging stress are largely unknown. In this study, the rapeseed (Brassica napus) inbred lines G230 and G218 were identified as waterlogging-tolerant rapeseed and waterlogging-sensitive rapeseed, respectively, through a potted waterlogging stress simulation and field waterlogging stress experiments. After six days of waterlogging stress at the seedling stage, the degree of leaf aging and root damage of the waterlogging-tolerant rapeseed G230 were lower than those of the waterlogging-sensitive rapeseed G218. A physiological analysis showed that waterlogging stress significantly increased the contents of malondialdehyde, soluble sugar, and hydrogen peroxide in rape leaves and roots. The transcriptomic and metabolomic analysis showed that the differential genes and the differential metabolites of waterlogging-tolerant rapeseed G230 were mainly enriched in the metabolic pathways, biosynthesis of secondary metabolites, flavonoid biosynthesis, and vitamin B6 metabolism. Compared to G218, the expression levels of some genes associated with flavonoid biosynthesis and vitamin B metabolism were higher in G230, such as CHI, DRF, LDOX, PDX1.1, and PDX2. Furthermore, some metabolites involved in flavonoid biosynthesis and vitamin B6 metabolism, such as naringenin and epiafzelechin, were significantly up-regulated in leaves of G230, while pyridoxine phosphate was only significantly down-regulated in roots and leaves of G218. Furthermore, foliar spraying of vitamin B6 can effectively improve the tolerance to waterlogging of G218 in the short term. These results indicate that flavonoid biosynthesis and vitamin B6 metabolism pathways play a key role in the waterlogging tolerance and hypoxia stress resistance of Brassica napus and provide new insights for improving the waterlogging tolerance and cultivating waterlogging-tolerant rapeseed varieties.

Responses of Cyanobacterial Crusts and Microbial Communities to Extreme Environments of the Stratosphere

How microbial communities respond to extreme conditions in the stratosphere remains unclear. To test this effect, cyanobacterial crusts collected from Tengger Desert were mounted to high balloons and briefly exposed (140 min) to high UV irradiation and low temperature in the stratosphere at an altitude of 32 km. Freezing and thawing treatments were simulated in the laboratory in terms of the temperature fluctuations during flight. Microbial community composition was characterized by sequencing at the level of DNA and RNA. After exposure to the stratosphere, the RNA relative abundances of Kallotenue and Longimicrobium increased by about 2-fold, while those of several dominant cyanobacteria genera changed slightly. The RNA relative abundances of various taxa declined after freezing, but increased after thawing, whereas cyanobacteria exhibited an opposite change trend. The DNA and RNA relative abundances of Nitrososphaeraceae were increased by 1.4~2.3-fold after exposure to the stratosphere or freezing. Exposure to stratospheric environmental conditions had little impact on the total antioxidant capacity, photosynthetic pigment content, and photosynthetic rate, but significantly increased the content of exopolysaccharides by 16%. The three treatments (stratospheric exposure, freezing, and thawing) increased significantly the activities of N-acetyl-β-D-glucosidase (26~30%) and β-glucosidase (14~126%). Our results indicated cyanobacterial crust communities can tolerate exposure to the stratosphere. In the defense process, extracellular organic carbon degradation and transformation play an important role. This study makes the first attempt to explore the response of microbial communities of cyanobacterial crusts to a Mars-like stratospheric extreme environment, which provides a new perspective for studying the space biology of earth communities.

Impact of Cold Stress on Leaf Structure, Photosynthesis, and Metabolites in Camellia weiningensis and C. oleifera Seedlings

Camellia weiningensis Y. K. Li. sp. nov. (CW) is an endemic oil-tea species in Guizhou province, distributed in the alpine karst area, which exhibits cold resistance and better economic characters than C. oleifera (CO). The mechanism of cold response in CW seedlings has not been studied in depth. Herein, we performed anatomical, physiological, and metabolic analyses to assess the impact of cold stress on leaf structure, photosynthesis, and metabolites in CW and CO seedlings. Anatomical analysis of leaves showed CW seedlings had greater leaf and palisade thicknesses, tissue structure tightness, and palisade-spongy tissue ratio to enhance chilling stress (4 °C) tolerance, but freezing stress (−4 °C) caused loosening of the leaf tissue structure in both CW and CO seedlings. Photosynthetic analysis showed a reduction in the chlorophyll (Chl) fluorescence (Fv/Fm) and photosynthetic parameters under freezing stress in both CW and CO seedlings. Cold stress increased the abscisic acid (ABA) contents in both the Camellia species, and CW exhibited the highest ABA content under −4 °C treatment. Additionally, the indole-3-acetic acid (IAA) content was also increased in CW in response to cold stress. An obviously distinct metabolite composition was observed for CW and CO under different temperatures, and significantly changed metabolites (SCMs) were enriched under freezing stress. Prenol lipids, organooxygen compounds, and fatty acyls were the main metabolites in the two Camellia species in response to cold stress. The top key SCMs, such as medicoside G, cynarasaponin F, yuccoside C, and methionyl-proline were downregulated under freezing stress in both CW and CO. The contents of some key metabolites associated with sugar metabolism, such as UDP-glucose, UDP-D-apiose, and fructose 6-phosphate, were higher in CW than in CO, which may contribute to enhancing the cold resistance in CW. Our findings are helpful in explaining how CW adapt to alpine karst cold environments, and will provide a reference for cold tolerance improvement and application of stress-resistant breeding of Camellia in alpine and cold areas.

Temperature-phase transcriptomics reveals that hormones and sugars in the phloem of grape participate in tolerance during cold acclimation

Most of the upregulated genes contributed to the accumulation of soluble sugars and ABA in the phloem of 'Vitis amurensis' compared to 'Merlot' during cold acclimation. Extreme cold is one of the dominant abiotic factors affecting grape yield and quality. However, the changes in sugars, phytohormones, and gene expression in the branch phloem of different tolerant grape varieties during cold acclimation remain elusive. The data supported that with decreasing temperature, the contents of fructose, sucrose, and ABA in the phloem of Vitis amurensis (cold-tolerant, T) and 'Merlot' (cold-sensitive, S) increased during cold acclimation, and these indicators were higher in T than in S. Furthermore, the activities of sucrose synthetase, sucrose phosphate synthetase, and acid invertase peaked in the early phase of cold acclimation (approximately 5 °C) compared to other phases (approximately 28 °C, 0 °C, - 5 °C and - 10 °C). Moreover, the RNA sequencing results helped identify a total of 11,343 differentially expressed genes in the phloem of T and S, among which 4912 were upregulated and 6431 were downregulated. In the abscisic acid pathway, CRTISO, PSPY1-1, CYCP707A4-2, PYL4-1, PYL4-2, P2C08, SAPK2, TARAB1, and DBF3 were more highly expressed in T than in S. In the starch and sucrose metabolism pathway, HXK1, PGMP, GLGL1, SUS6, VCINV, BGL11, SSY1, GPS, BAM1 and BAM3 were also more highly expressed in T than in S. Moreover, the genes related to oxidative phosphorylation, such as NDHF, ND4, ND1, NAD7, NAD2, ATPB, YMF19, ATP9, PMA1 and AHA8, were upregulated in T. These results will be beneficial for understanding the potential differences in tolerance across two different cold-tolerant grapes with respect to sugar metabolism and gene expression.

Physiological and comparative transcriptome analyses reveal the mechanisms underlying waterlogging tolerance in a rapeseed anthocyanin-more mutant

Background

Rapeseed (Brassica napus) is the second largest oil crop worldwide. It is widely used in food, energy production and the chemical industry, as well as being an ornamental. Consequently, it has a large economic value and developmental potential. Waterlogging is an important abiotic stress that restricts plant growth and development. However, little is known about the molecular mechanisms underlying waterlogging tolerance in B. napus.

Results

In the present study, the physiological changes and transcriptomes of germination-stage rapeseed in response to waterlogging stress were investigated in the B. napus cultivar ‘Zhongshuang 11’ (ZS11) and its anthocyanin-more (am) mutant, which was identified in our previous study. The mutant showed stronger waterlogging tolerance compared with ZS11, and waterlogging stress significantly increased anthocyanin, soluble sugar and malondialdehyde contents and decreased chlorophyll contents in the mutant after 12 days of waterlogging. An RNA-seq analysis identified 1370 and 2336 differently expressed genes (DEGs) responding to waterlogging stress in ZS11 and am, respectively. An enrichment analysis revealed that the DEGs in ZS11 were predominately involved in carbohydrate metabolism, whereas those in the am mutant were particularly enriched in plant hormone signal transduction and response to endogenous stimulation. In total, 299 DEGs were identified as anthocyanin biosynthesis-related structural genes (24) and regulatory genes encoding transcription factors (275), which may explain the increased anthocyanin content in the am mutant. A total of 110 genes clustered in the plant hormone signal transduction pathway were also identified as DEGs, including 70 involved in auxin and ethylene signal transduction that were significantly changed in the mutant. Furthermore, the expression levels of 16 DEGs with putative roles in anthocyanin accumulation and biotic/abiotic stress responses were validated by quantitative real-time PCR as being consistent with the transcriptome profiles.

Conclusion

This study provides new insights into the molecular mechanisms of increased anthocyanin contents in rapeseed in response to waterlogging stress, which should be useful for reducing the damage caused by waterlogging stress and for further breeding new rapeseed varieties with high waterlogging tolerance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13068-022-02155-5.

Integrated Analysis of Physiological, mRNA Sequencing, and miRNA Sequencing Data Reveals a Specific Mechanism for the Response to Continuous Cropping Obstacles in Pogostemon cablin Roots

Pogostemon cablin (patchouli) is a commercially important medicinal and industrial crop grown worldwide for its medicinal and aromatic properties. Patchoulol and pogostone, derived from the essential oil of patchouli, are considered valuable components in the cosmetic and pharmaceutical industries. Due to its high application value in the clinic and industry, the demand for patchouli is constantly growing. Unfortunately, patchouli cultivation has suffered due to severe continuous cropping obstacles, resulting in a significant decline in yield and quality. Moreover, the physiological and transcriptional changes in patchouli in response to continuous cropping obstacles remain unclear. This has greatly restricted the development of the patchouli industry. To explore the mechanism underlying the rapid response of patchouli roots to continuous cropping stress, integrated analysis of the transcriptome and miRNA profiles of patchouli roots under continuous and noncontinuous cropping conditions in different growth periods was conducted using RNA sequencing (RNA-seq) and miRNA-seq and complemented with physiological data. The physiological and biochemical results showed that continuous cropping significantly inhibited root growth, decreased root activity, and increased the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and the levels of osmoregulators (malondialdehyde, soluble protein, soluble sugar, and proline). Subsequently, we found 4,238, 3,494, and 7,290 upregulated and 4,176, 3,202, and 8,599 downregulated differentially expressed genes (DEGs) in the three growth periods of continuously cropped patchouli, many of which were associated with primary carbon and nitrogen metabolism, defense responses, secondary metabolite biosynthesis, and transcription factors. Based on miRNA-seq, 927 known miRNAs and 130 novel miRNAs were identified, among which 67 differentially expressed miRNAs (DEMIs) belonging to 24 miRNA families were induced or repressed by continuous cropping. By combining transcriptome and miRNA profiling, we obtained 47 miRNA-target gene pairs, consisting of 18 DEMIs and 43 DEGs, that likely play important roles in the continuous cropping response of patchouli. The information provided in this study will contribute to clarifying the intricate mechanism underlying the patchouli response to continuous cropping obstacles. In addition, the candidate miRNAs and genes can provide a new strategy for breeding continuous cropping-tolerant patchouli.

Characterization of the early gene expression profile in Populus ussuriensis under cold stress using PacBio SMRT sequencing integrated with RNA-seq reads

Populus ussuriensis is an important and fast-growing afforestation plant species in north-eastern China. The whole-genome sequencing of P. ussuriensis has not been completed. Also, the transcriptional network of P. ussuriensis response to cold stress remains unknown. To unravel the early response of P. ussuriensis to chilling (3 °C) stress and freezing (-3 °C) stresses at the transcriptional level, we performed single-molecule real-time (SMRT) and Illumina RNA sequencing for P. ussuriensis. The SMRT long-read isoform sequencing led to the identification of 29,243,277 subreads and 575,481 circular consensus sequencing reads. Approximately 50,910 high-quality isoforms were generated, and 2272 simple sequence repeats and 8086 long non-coding RNAs were identified. The Ca2+ content and abscisic acid (ABA) content in P. ussuriensis were significantly increased under cold stresses, while the value in the freezing stress treatment group was significantly higher than the chilling stress treatment group. A total of 49 genes that are involved in the signal transduction pathways related to perception and transmission of cold stress signals, such as the Ca2+ signaling pathway, ABA signaling pathway and MAPK signaling cascade, were found to be differentially expressed. In addition, 158 transcription factors from 21 different families, such as MYB, WRKY and AP2/ERF, were differentially expressed during chilling and freezing treatments. Moreover, the measurement of physiological indicators and bioinformatics observations demonstrated the altered expression pattern of genes involved in reactive oxygen species balance and the sugar metabolism pathway during chilling and freezing stresses. This is the first report of the early responses of P. ussuriensis to cold stress, which lays the foundation for future studies on the regulatory mechanisms in cold-stress response. In addition the full-length reference transcriptome of P. ussuriensis deciphered could be used in future studies on P. ussuriensis.

Secondary Metabolism and Hormone Response Reveal the Molecular Mechanism of Triploid Mulberry (Morus Alba L.) Trees Against Drought

The improvement of a plant's tolerance to drought is a major endeavor in agriculture. Polyploid plants often exhibit enhanced stress tolerance relative to their diploid progenitor, but the matching stress tolerance is still little understood. Own-rooted stem cuttings of mulberry (Morus alba L.) cultivar Shinichinose (2n = 2x = 28) and Shaansang-305 (2n = 3x = 42) were used in this study, of which the latter (triploid) has more production and application purposes. The responses of triploid Shaansang-305 and diploid progenitor ShinIchinose under drought stress were compared through an investigation of their physiological traits, RNA-seq, and secondary metabolome analysis. The results showed that the triploid exhibited an augmented abscisic acid (ABA) content and a better stress tolerance phenotype under severe drought stress. Further, in the triploid plant some genes (TSPO, NCED3, and LOC21398866) and ATG gene related to ABA signaling showed significantly upregulated expression. Interestingly, the triploid accumulated higher levels of RWC and SOD activity, as well as more wax on the leaf surface, but with less reductive flavonoid than in diploid. Our results suggest triploid plants may better adapt to with drought events. Furthermore, the flavonoid metabolism involved in drought resistance identified here may be of great value to medicinal usage of mulberry. The findings presented here could have substantial implications for future studies of crop breeding.

Genome-wide identification and expression profiling of DREB genes in Saccharum spontaneum

Background

The dehydration-responsive element-binding proteins (DREBs) are important transcription factors that interact with a DRE/CRT (C-repeat) sequence and involve in response to multiple abiotic stresses in plants. Modern sugarcane are hybrids from the cross between Saccharum spontaneum and Saccharum officinarum, and the high sugar content is considered to the attribution of S. officinaurm, while the stress tolerance is attributed to S. spontaneum. To understand the molecular and evolutionary characterization and gene functions of the DREBs in sugarcane, based on the recent availability of the whole genome information, the present study performed a genome-wide in silico analysis of DREB genes and transcriptome analysis in the polyploidy S. spontaneum.

Results

Twelve DREB1 genes and six DREB2 genes were identified in S. spontaneum genome and all proteins contained a conserved AP2/ERF domain. Eleven SsDREB1 allele genes were assumed to be originated from tandem duplications, and two of them may be derived after the split of S. spontaneum and the proximal diploid species sorghum, suggesting tandem duplication contributed to the expansion of DREB1-type genes in sugarcane. Phylogenetic analysis revealed that one DREB2 gene was lost during the evolution of sugarcane. Expression profiling showed different SsDREB genes with variable expression levels in the different tissues, indicating seven SsDREB genes were likely involved in the development and photosynthesis of S. spontaneum. Furthermore, SsDREB1F, SsDREB1L, SsDREB2D, and SsDREB2F were up-regulated under drought and cold condition, suggesting that these four genes may be involved in both dehydration and cold response in sugarcane.

Conclusions

These findings demonstrated the important role of DREBs not only in the stress response, but also in the development and photosynthesis of S. spontaneum.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07799-5.