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Transcriptional regulation of the high-affinity K+ (HAK) transporter gene is an important mechanism of plant response to low potassium stress. Cloning and analysis of the promoter of potassium transporter gene is not only helpful to its expression pattern and regulation mechanism but also important to improve the potassium absorption efficiency in sugarcane. The potassium transporter gene ScHAK10 is highly expressed and induced by low potassium stress in sugarcane, but the functions of its promoter is still unclear. In the present article, the 1918 bp promoter region of the ScHAK10 gene (pScHAK10) was cloned by genomic walking technique. Computational analysis affirmed the existence of abiotic stress-responsive cis and core cis-elements, such as TATA box, CAAT box, phytohormone responsive, stress response and light response motifs. GUS histochemical staining of transgenic Arabidopsis thaliana seedlings showed that the leaf, corolla, and root tip were deeply stained. The 5′-terminal deletion of the promoter was cloned, and the lengths of 1918 bp (full), 1623 bp (Q1), 1332 bp (Q2), 957 bp (Q3), 576 bp (Q4), and 357 bp (Q5) were cloned into the GUS reporter vector for A. thaliana transient transformation. The transgenic plants generated through a single event exhibited a promising expression of the GUS reporter protein, which was treated with salt, low potassium, IAA and cold stress conditions. The results showed that the promoter activity correlates with the promoter fragment's length, and the long promoter fragment exhibits higher training. The Q5 was the least active and could not drive GUS expression. Under abiotic stress, the expression of GUS enzyme activity varies among different promoter fragments. Under low potassium and high salt stress, Q3 and Q4 showed the highest promoter activity. The Q1 and Q4 led the highest promoter activity during IAA and cold stress. These findings help to understand the molecular mechanism of ScHAK10 expression regulation and could be an excellent tool for future crop improvement. [ABSTRACT FROM AUTHOR]

Abstract Plant cellulose synthase is one of the important glycosyltransferases, which catalyzes the synthesis of the paracrystalline of H-bonded-β-(1,4)-glucose chains. This study isolated the cellulose synthase 3 (Ces3) sequence from sugarcane (Saccharum officinarum L.) leaves. SoCes3 (GenBank accession No. MG324347) has a full-length cDNA sequence of 3625 bp. It contains an open reading frame (3225 bp), encoding 1074 amino acids with a molecular weight of about 120.89 kDa and isoelectric point of 6.26. SoCes3 protein showed high activity with other plant cellulose synthases. The recombinant protein contains plant cellulose synthase (Ces) protein conservative domains. In subcellular localization experiments, the fusion protein of SoCes3 with green fluorescent protein (GFP) was specifically localized in the cell membrane. The gene expression of SoCes3 was found in the leaf, leaf sheath, and internodes of the sugarcane stem. The highest expression level was found in the internode, especially with the highest expression level in the 5th internode and lowest in the leaves, and the gene expression level of SoCes3 was upregulated by PP333 and not in gibberellic acid-treated plants. It was conducted in tobacco plants to understand the biotechnological potential of SoCes3. The contents of cellulose and lignin were increased in SoCes3-overexpressing tobacco. Transcriptomic analysis showed that the transgenic tobacco induced different genes associated with different biological regulatory processes. Differentially expressed genes (DEGs) mediated plant hormone signal transduction, starch and sucrose metabolism signaling pathways were widely induced and mostly upregulated. The transcription levels in SoCes3-overexpressing transgenic lines were higher than wild-type. Graphical Abstract

Plant cellulose synthase is one of the important glycosyltransferases, which catalyzes the synthesis of the paracrystalline of H-bonded-β-(1,4)-glucose chains. This study isolated the cellulose synthase 3 (Ces3) sequence from sugarcane (Saccharum officinarum L.) leaves. SoCes3 (GenBank accession No. MG324347) has a full-length cDNA sequence of 3625 bp. It contains an open reading frame (3225 bp), encoding 1074 amino acids with a molecular weight of about 120.89 kDa and isoelectric point of 6.26. SoCes3 protein showed high activity with other plant cellulose synthases. The recombinant protein contains plant cellulose synthase (Ces) protein conservative domains. In subcellular localization experiments, the fusion protein of SoCes3 with green fluorescent protein (GFP) was specifically localized in the cell membrane. The gene expression of SoCes3 was found in the leaf, leaf sheath, and internodes of the sugarcane stem. The highest expression level was found in the internode, especially with the highest expression level in the 5th internode and lowest in the leaves, and the gene expression level of SoCes3 was upregulated by PP333 and not in gibberellic acid-treated plants. It was conducted in tobacco plants to understand the biotechnological potential of SoCes3. The contents of cellulose and lignin were increased in SoCes3-overexpressing tobacco. Transcriptomic analysis showed that the transgenic tobacco induced different genes associated with different biological regulatory processes. Differentially expressed genes (DEGs) mediated plant hormone signal transduction, starch and sucrose metabolism signaling pathways were widely induced and mostly upregulated. The transcription levels in SoCes3-overexpressing transgenic lines were higher than wild-type. [ABSTRACT FROM AUTHOR]

Studies on the development of the root system can provide important information about responses to different management strategies, such as the use of lower quality water, also evaluating the interaction between plants and the physical properties of the soil. This study tested the hypothesis that irrigation with treated sewage effluent (TSE) supplies the water needs of sugarcane plants, increasing root growth and improving the physical properties of the soil. We evaluated the effects of subsurface dripping with TSE or surface reservoir water (SRW) on the root development of first ratoon cane (Saccharum officinarum L.) and the physical properties of dystrophic red latosol. Irrigation treatments were applied at 20 and 40 cm and soil properties were evaluated at soil depth layers of 0–20, 20–40, 40–60, and 60–80 cm. We verified that under irrigation with TSE and SRW, shallower soil layers present better porosity, soil aggregation, and aggregate stability conditions, parameters that improve the root system development and plant growth. On the other hand, deeper soil layers have lower macroporosity and higher total clay volume, indicating the possibility of compaction and greater limitations for sugarcane root growth. These results are important for understanding soil quality and provide significant information for agricultural management and for the implementation of sustainable soil conservation practices. This study shows the efficiency of TSE as an alternative water source for sugarcane crops. [ABSTRACT FROM AUTHOR]

The use of microbial inoculants has become an effective alternative for increasing crop yields, reducing production costs, and improving environmental sustainability. Farmers are very interested in microbial inoculants involved in the solubilization of non-labile phosphorus due to the increasing demand for phosphate fertilizers and the scarcity of natural sources of this nutrient. Thus, the Brazilian Agricultural Research Corporation (Embrapa), in partnership with the Simbiose Company (Rio Grande do Sul, Brazil), has developed a commercial phosphate-solubilizing inoculant combining the Bacillus subtilis CNPMS2084 and Bacillus megaterium CNPMS119 strains. The present work evaluated the effect of different doses of this Bacillus strain inoculant in combination with phosphate fertilization on sugarcane crops in three experimental fields for two successive production seasons (plant cane and first ratoon). Vegetation indices (VIs) were calculated with the help of aerial images collected regularly during the phenological phases of vegetative growth and ripening and used in association with weather and yield data to develop a predictive model for the effect of the bioinoculant on the sugarcane crop. The results showed that the doses of 500 and 750 mL/ha of Bacillus strain inoculant applied in the planting furrow and during ratoon management were the most effective to increase tons of cane per hectare (TCH) and tons of sucrose per hectare (TSH) compared to treatments without inoculant application. These results agree with the forecast generated by the statistical model developed to predict the impact of the bioinoculant on the increase in sugarcane biomass. Afterward, the fitness of the model to estimate the effect of the Bacillus strain inoculant on the sugarcane yield was demonstrated when field data from commercial areas of sugarcane treated with the bioinoculant were compared to data from control fields without application, confirming the positive effect of the commercial Bacillus strain inoculant for sugarcane crops as well as the model's effectiveness in handling and predicting yield from data obtained from commercial areas. [ABSTRACT FROM AUTHOR]

The growing demand for food production has led to an increase in agricultural areas, including many with low and irregular rainfall, stressing the importance of studies aimed at mitigating the harmful effects of water stress. From this perspective, the objective of this study was to evaluate calcium pyruvate as an attenuator of water deficit on chlorophyll a fluorescence of five sugarcane genotypes. The experiment was conducted in a plant nursery where three management strategies (E1—full irrigation, E2—water deficit with the application of 30 mM calcium pyruvate, and E3—water deficit without the application of calcium pyruvate) and five sugarcane genotypes (RB863129, RB92579, RB962962, RB021754, and RB041443) were tested, distributed in randomized blocks, in a 3 × 5 factorial design with three replications. There is dissimilarity in the fluorescence parameters and photosynthetic pigments of the RB863129 genotype in relation to those of the RB041443, RB96262, RB021754, and RB92579 genotypes. Foliar application of calcium pyruvate alleviates the effects of water deficit on the fluorescence parameters of chlorophyll a and photosynthetic pigments in sugarcane, without interaction with the genotypes. However, subsequent validation tests will be necessary to test and validate the adoption of this technology under field conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT The aim of the study was to characterize the bioactive compounds present in sugarcane syrup, analyze the color, to evaluate the antioxidant activity as well as the stability of the bioactive compounds during a 60-day storage under freezing conditions. The experiment was conducted with five sugarcane varieties grown in Canguçu-RS. The content of carotenoids, total phenolic compounds, flavonoids, vitamin C and chlorophylls was determined, and also the antioxidant activity and color were also evaluated. The content of carotenoids (1.82-6.67µg.g), total phenolic compounds (191.06-226.54 mg EAG.L-1), flavonoids (70.73-189.57mg EQ.g-1), vitamin C (0.10-0.35 mg ascorbic acid .100g-1), total chlorophylls (36.13-37.67 g.kg-1), and percentage of antioxidant activity (50.92-68.76%) varied by cultivar. The content of chlorophyll b was higher than the content of chlorophyll a in all cultivars. The color analysis showed that the samples had a strong tendency to green and yellow color. The content of carotenoids increased during 60 days of storage, while the content of phenolic compounds and chlorophylls decreased. The percentage of antioxidant activity decreased after 30 days of storage. It can be concluded that the sugarcane grown in Canguçu-RS had a high content of bioactive compounds, adequate color and high antioxidant activity when compared to the literature.

ABSTRACT Several studies on the kinetics of sugarcane’s fiber digestion have been published, but, to date, no study has evaluated the influence of sugarcane rind on the digestion of fresh sugarcane by ruminants. This study aimed to evaluate the effects of sugarcane components (rind and pith) on chemical composition, in vitro digestibility, metabolizable energy, and sugarcane quality. A randomized block design was used in a split-plot scheme with five sugarcane genotypes [plot] (RB068027, RB058046, RB987917, RB867515, and RB855536) and three sugarcane components [sub-plot] (rind, pith, and whole cane), Each treatment consisted of four replicates. The chemical composition, in vitro gas production, in vitro digestibility, metabolizable energy, and sugarcane quality were evaluated. No interaction between components and genotypes was observed for the variables analyzed herein. Although the rind had a higher crude protein content, it showed a large amount of insoluble crude protein. The rind had higher fibrous fractions, comprising 87.33 % of the indigestible fraction of the neutral detergent fiber (NDF). The sugarcane rind showed ~ 71.20 % more lignin than the pith tissue. Further, the rind decreased by 6.5 % in vitro dry matter digestibility compared to the whole sugarcane. The in vitro NDF digestibility of the rind was 18.38 % lower than the whole sugarcane. The RB068027 genotype showed the lowest sugarcane quality. Despite the higher content of potentially digestible neutral detergent fiber (pdNDF) in the rind, its high lignin content influences the quality of the final fibrous fractions of sugarcane and negatively impacts the nutritional value. The genotypes do not differ nutritionally, but RB855536 presented higher biomass and energy yields.

Diseases caused by fungi associated with adverse weather conditions are one of the main causes of decreases in sugarcane production. This study aimed to develop a protocol for a fast identification of Phaeocytostroma sacchari, which is the causal agent of bark rot in sugarcane. The reference sequences of three DNA regions of P. sacchari, namely internal transcribed spacer, ribosomal large subunit and translation elongation factor 1-alpha (TEF1-α), were analyzed with specific primers design. The specific primers generated that aligned in their entirety with P. sacchari were selected and synthesized. Polymerase chain reaction (PCR) assays were performed to confirm the primer specificity, using P. sacchari isolates and 10 species of other genera. Two sets of primers that amplify the TEF-1α region (PsF1/Psf1 and PsF2/PsR2) showed a high specificity and sensitivity in detecting P. sacchari using conventional PCR, what will allow large-scale surveys of this pathogen in sugarcane crops.

Studies on the development of the root system can provide important information about responses to different management strategies, such as the use of lower quality water, also evaluating the interaction between plants and the physical properties of the soil. This study tested the hypothesis that irrigation with treated sewage effluent (TSE) supplies the water needs of sugarcane plants, increasing root growth and improving the physical properties of the soil. We evaluated the effects of subsurface dripping with TSE or surface reservoir water (SRW) on the root development of first ratoon cane (Saccharum officinarum L.) and the physical properties of dystrophic red latosol. Irrigation treatments were applied at 20 and 40 cm and soil properties were evaluated at soil depth layers of 0–20, 20–40, 40–60, and 60–80 cm. We verified that under irrigation with TSE and SRW, shallower soil layers present better porosity, soil aggregation, and aggregate stability conditions, parameters that improve the root system development and plant growth. On the other hand, deeper soil layers have lower macroporosity and higher total clay volume, indicating the possibility of compaction and greater limitations for sugarcane root growth. These results are important for understanding soil quality and provide significant information for agricultural management and for the implementation of sustainable soil conservation practices. This study shows the efficiency of TSE as an alternative water source for sugarcane crops.

The growing demand for food production has led to an increase in agricultural areas, including many with low and irregular rainfall, stressing the importance of studies aimed at mitigating the harmful effects of water stress. From this perspective, the objective of this study was to evaluate calcium pyruvate as an attenuator of water deficit on chlorophyll a fluorescence of five sugarcane genotypes. The experiment was conducted in a plant nursery where three management strategies (E1—full irrigation, E2—water deficit with the application of 30 mM calcium pyruvate, and E3—water deficit without the application of calcium pyruvate) and five sugarcane genotypes (RB863129, RB92579, RB962962, RB021754, and RB041443) were tested, distributed in randomized blocks, in a 3 × 5 factorial design with three replications. There is dissimilarity in the fluorescence parameters and photosynthetic pigments of the RB863129 genotype in relation to those of the RB041443, RB96262, RB021754, and RB92579 genotypes. Foliar application of calcium pyruvate alleviates the effects of water deficit on the fluorescence parameters of chlorophyll a and photosynthetic pigments in sugarcane, without interaction with the genotypes. However, subsequent validation tests will be necessary to test and validate the adoption of this technology under field conditions.