Key role of K+ and Ca2+ in high-yield ethanol production by S. Cerevisiae from concentrated sugarcane molasses.

BACKGROUND: Saccharomyces cerevisiae is an important microorganism in ethanol synthesis, and with sugarcane molasses as the feedstock, ethanol is being synthesized sustainably to meet growing demands. However, high-concentration ethanol fermentation based on high-concentration sugarcane molasses-which is needed for reduced energy consumption of ethanol distillation at industrial scale-is yet to be achieved. RESULTS: In the present study, to identify the main limiting factors of this process, adaptive laboratory evolution and high-throughput screening (Py-Fe3+) based on ARTP (atmospheric and room-temperature plasma) mutagenesis were applied. We identified high osmotic pressure, high temperature, high alcohol levels, and high concentrations of K+, Ca2+, K+ and Ca2+ (K+&Ca2+), and sugarcane molasses as the main limiting factors. The robust S. cerevisiae strains of NGT-F1, NGW-F1, NGC-F1, NGK+, NGCa2+ NGK+&Ca2+-F1, and NGTM-F1 exhibited high tolerance to the respective limiting factor and exhibited increased yield. Subsequently, ethanol synthesis, cell morphology, comparative genomics, and gene ontology (GO) enrichment analysis were performed in a molasses broth containing 250 g/L total fermentable sugars (TFS). Additionally, S. cerevisiae NGTM-F1 was used with 250 g/L (TFS) sugarcane molasses to synthesize ethanol in a 5-L fermenter, giving a yield of 111.65 g/L, the conversion of sugar to alcohol reached 95.53%. It is the highest level of physical mutagenesis yield at present. CONCLUSION: Our results showed that K+ and Ca2+ ions primarily limited the efficient production of ethanol. Then, subsequent comparative transcriptomic GO and pathway analyses showed that the co-presence of K+ and Ca2+ exerted the most prominent limitation on efficient ethanol production. The results of this study might prove useful by promoting the development and utilization of green fuel bio-manufactured from molasses.

Agricultural Waste Management by Production of Second-Generation Bioethanol from Sugarcane Bagasse Using Indigenous Yeast Strain.

In the wake of rapid industrialization and burgeoning transportation networks, the escalating demand for fossil fuels has accelerated the depletion of finite energy reservoirs, necessitating urgent exploration of sustainable alternatives. To address this, current research is focusing on renewable fuels like second-generation bioethanol from agricultural waste such as sugarcane bagasse. This approach not only circumvents the contentious issue of food-fuel conflicts associated with biofuels but also tackles agricultural waste management. In the present study indigenous yeast strain, Clavispora lusitaniae QG1 (MN592676), was isolated from rotten grapes to ferment xylose sugars present in the hemicellulose content of sugarcane bagasse. To liberate the xylose sugars, dilute acid pretreatment was performed. The highest reducing sugars yield was 1.2% obtained at a temperature of 121 °C for 15 min, a solid-to-liquid ratio of 1:25 (% w/v), and an acid concentration of 1% dilute acid H2SO4 that was significantly higher (P < 0.001) yield obtained under similar conditions at 100 °C for 1 h. The isolated strain was statistically optimized for fermentation process by Plackett-Burman design to achieve the highest ethanol yield. Liberated xylose sugars were completely utilized by Clavispora lusitaniae QG1 (MN592676) and gave 100% ethanol yield. This study optimizes both fermentation process and pretreatment of sugarcane bagasse to maximize bioethanol yield and demonstrates the ability of isolated strain to effectively utilize xylose as a carbon source. The desirable characteristics depicted by strain Clavispora lusitaniae shows its promising utilization in management of industrial waste like sugarcane bagasse by its conversion into renewable biofuels like bioethanol.

Optimizing herbicide selection for pre-emergence control of itchgrass and cypressvine morningglory in sugarcane.

The aim of this study was to assess the efficacy of herbicides in association to control Rottboellia exaltata and Ipomoea quamoclit during pre-emergence while also to evaluate the potential impact on the sugarcane. The experimental design employed a randomized block with seven treatments and four replications. The treatments were: 1 - no herbicide application; 2 - indaziflam + sulfentrazone; 3 - indaziflam + diclosulam; 4 - indaziflam + tebuthiuron; 5 - flumioxazin + diclosulam, 6 - flumioxazin + pyroxasulfone and 7 - clomazone + sulfentrazone. The evaluated parameters were: percentage of weeds control, green coverage percentage (Canopeo® system), weed biomass (g m-2), itchgrass height, and sugarcane tiller. Several herbicide associations have been proven effective alternatives for managing itchgrass and cypressvine morningglory. The most successful treatments for itchgrass control were indaziflam + tebuthiuron (100%) and indaziflam + diclosulam (97%), whereas for cypressvine morningglory, the betters were indaziflam + sulfentrazone (97%), indaziflam + diclosulam (98%), indaziflam + tebuthiuron (97%), flumioxazin + diclosulam (94%), and clomazone + sulfentrazone (96%). All treatments reduced the weed biomass, with indaziflam + tebuthiuron being the safest option for protecting sugarcane.

ß-Carotene production from sugarcane molasses by a newly isolated Rhodotorula toruloides L/24-26-1.

Production of carotenoids by yeast fermentation is an advantaged technology due to its easy scaling and safety. Nevertheless, carotenoid production needs an economic culture medium and other efficient yeast stains. The study aims to isolate and identify a yeast strain capable of producing carotenoids using a cost-effective substrate. A new strain was identified as Rhodotorula toruloides L/24-26-1, which can produce carotenoids at different pretreated and unpretreated sugarcane molasses concentrations (40 and 80 g/L). The highest biomass concentration (18.6 ± 0.6 g/L) was reached in the culture using 80 g/L of hydrolyzed molasses. On the other hand, the carotenoid accumulation reached the maximum value using pretreated molasses at 40 g/L (715.4 ± 15.1 µg/g d.w). In this case, the ß-carotene was 1.5 times higher than that on the control medium. The yeast growth in molasses was not correlated with carotenoid production. The most outstanding production of The DPPH, ABTS, and FRAP tests demonstrated the antioxidant activity of the obtained carotenogenic extracts. This research demonstrated the R. toruloides L/24-26-1 strain biotechnological potential for carotenoid compounds. The yeast produces carotenoids with antioxidant activity in an inexpensive medium, such as sulfuric acid pretreated and unpretreated molasses.

Recent advances in genome editing strategies for balancing growth and defence in sugarcane (Saccharum officinarum).

Sugarcane (Saccharum officinarum ) has gained more attention worldwide in recent decades because of its importance as a bioenergy resource and in producing table sugar. However, the production capabilities of conventional varieties are being challenged by the changing climates, which struggle to meet the escalating demands of the growing global population. Genome editing has emerged as a pivotal field that offers groundbreaking solutions in agriculture and beyond. It includes inserting, removing or replacing DNA in an organism's genome. Various approaches are employed to enhance crop yields and resilience in harsh climates. These techniques include zinc finger nuclease (ZFN), transcription activator-like effector nuclease (TALEN) and clustered regularly interspaced short palindromic repeats/associated protein (CRISPR/Cas). Among these, CRISPR/Cas is one of the most promising and rapidly advancing fields. With the help of these techniques, several crops like rice (Oryza sativa ), tomato (Solanum lycopersicum ), maize (Zea mays ), barley (Hordeum vulgare ) and sugarcane have been improved to be resistant to viral diseases. This review describes recent advances in genome editing with a particular focus on sugarcane and focuses on the advantages and limitations of these approaches while also considering the regulatory and ethical implications across different countries. It also offers insights into future prospects and the application of these approaches in agriculture.

One pot synthesis of furan-modified lignin from agricultural waste via lignin-first approach.

This study investigated a lignin-first approach to produce furan-modified lignin from sugarcane bagasse (SB), rice hull (RH), and sunn hemp biomass (SHB) using 5 methylfurfural (MF) and 5 methul-2-furanmethanol (MFM). The reaction time (5 h) was selected based on the delignification of SB using methanol and Ru/C catalyst which yielded the highest hydroxyl content. Delignification of SB with various MF weight ratios (1:1, 1:2, 1:3, 2:1, and 3:1) revealed that 1:1 and 2:1 ratios produced the highest hydroxyl content (7.7 mmol/g) and bio-oil yield (23.2 % wt% total weight). Further exploration identified that RH and MF at 1:1 ratio and SHB and MF at a 2:1 ratio produced the highest hydroxyl content (13.0 mmol/g) and bio-oil yield (31.6 % wt% tot. weight). This study developed a one-step method to extract and modify lignin with furan compounds simultaneously while opening new avenues for developing value-added products.

Transcriptional Regulation of SugarCane Response to Sporisorium scitamineum: Insights from Time-Course Gene Coexpression and Ca2+ Signaling.

Sugarcane response to Sporisorium scitamineum is determined by multiple major genes and numerous microeffector genes. Here, time-ordered gene coexpression networks were applied to explore the interaction between sugarcane and S. scitamineum. Totally, 2459 differentially expressed genes were identified and divided into 10 levels, and several stress-related subnetworks were established. Interestingly, the Ca2+ signaling pathway was activated to establish the response to sugarcane smut disease. Accordingly, two CAX genes (ScCAX2 and ScCAX3) were cloned and characterized from sugarcane. They were significantly upregulated under ABA stress but inhibited by MeJA treatment. Furthermore, overexpression of ScCAX2 and ScCAX3 enhanced the susceptibility of transgenic plants to the pathogen infection, suggesting its negative role in disease resistance. A regulatory model for ScCAX genes in disease response was thus depicted. This work helps to clarify the transcriptional regulation of sugarcane response to S. scitamineum stress and the function of the CAX gene in disease response.

Functional characterization of sugarcane ScFTIP1 reveals its role in Arabidopsis flowering.

The timing of floral transition is essential for reproductive success in flowering plants. In sugarcane, flowering time affects the production of sugar and biomass. Although the function of the crucial floral pathway integrators, FLOWERING LOCUS T (FT), in sugarcane, has been uncovered, the proteins responsible for FT export and the underlying mechanism remain unexplored. In this study, we identified a member of the multiple C2 domain and transmembrane region proteins (MCTPs) family in sugarcane, FT-interacting protein 1 (ScFTIP1), which was localized to the endoplasmic reticulum. Ectopic expression of ScFTIP1 in the Arabidopsis mutant ftip1-1 rescued the late-flowering phenotype. ScFTIP1 interacted with AtFT in vitro and in vivo assays. Additionally, ScFTIP1 interacted with ScFT1 and the floral inducer ScFT3. Furthermore, we found that the NAC member, ScNAC23, could directly bind to the ScFTIP1 promoter and negatively regulate its transcription. Overall, our findings revealed the function of ScFTIP1 and proposed a potential mechanism underlying flowering regulation in sugarcane.

Genome-wide identification of JAZ gene family in sugarcane and function analysis of ScJAZ1/2 in drought stress response and flowering regulation.

The JASMONATE ZIM DOMAIN (JAZ) proteins are a key inhibitors of the jasmonic acid (JA) signaling pathway that play an important role in the regulation of plant growth and development and environmental stress responses. However, there is no systematic identification and functional analysis of JAZ gene family members in sugarcane. In this study, a total of 49 SsJAZ genes were identified from the wild sugarcane species Saccharum spontaneum genome that were unevenly distributed on 13 chromosomes. Phylogenetic analysis showed that all SsJAZ members can be divided into six groups, and most of the SsJAZ genes contained photoreactive and ABA-responsive elements. RNA-seq analysis revealed that SsJAZ1-1/2/3/4 and SsJAZ7-1 were significantly upregulated under drought stress. The transcript level of ScJAZ1 which is the homologous gene of SsJAZ1 in modern sugarcane cultivars was upregulated by JA, PEG, and abscisic acid (ABA). Moreover, ScJAZ1 can interact with three other JAZ proteins to form heterodimers. The spatial and temporal expression analysis showed that SsJAZ2-1/2/3/4 were highly expressed in different tissues and growth stages and during the day-night rhythm between 10:00 and 18:00. Overexpression of ScJAZ2 in Arabidopsis accelerated flowering through activating the expression of AtSOC1, AtFT, and AtLFY. Moreover, the transcription level of ScJAZ2 was about 30-fold in the early-flowering sugarcane variety than that of the non-flowering variety, indicating ScJAZ2 positively regulated flowering. This first systematic analysis of the JAZ gene family and function analysis of ScJAZ1/2 in sugarcane provide key candidate genes and lay the foundation for sugarcane breeding.

Silicon induces ROS scavengers, hormone signalling, antifungal metabolites, and silicon deposition against brown stripe disease in sugarcane.

Bipolaris setariae is known to cause brown stripe disease in sugarcane, resulting in significant yield losses. Silicon (Si) has the potential to enhance plant growth and biotic resistance. In this study, the impact of Si on brown stripe disease was investigated across susceptible and resistant sugarcane varieties, utilizing four Si concentrations (0, 15, 30, and 45 g per barrel of Na2SiO3·5H2O). Si significantly reduced the incidence of brown stripe disease (7.41-59.23%) and alleviated damage to sugarcane growth parameters, photosynthetic parameters, and photosynthetic pigments. Submicroscopic observations revealed that Si induced the accumulation of silicified cells in leaves, reduced spore accumulation, decreased stomatal size, and protected organelles from B. setariae damage. In addition, Si increased the activity of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase), reduced reactive oxygen species production (malondialdehyde and hydrogen peroxide) and modulated the expression of genes associated with hormone signalling (PR1, TGA, AOS, AOC, LOX, PYL8, and SnRK2), leading to the accumulation of abscisic acid and jasmonic acid and inhibiting SA synthesis. Si also activated the activity of metabolism-related enzymes (polyphenol oxidase and phenylalanine ammonia lyase) and the gene expression of PAL-dependent genes (PAL, C4H, and 4CL), regulating the accumulation of metabolites, such as chlorogenic acid and lignin. The antifungal test showed that chlorogenic acid (15ug µL-1) had a significant inhibitory effect on the growth of B. setariae. This study is the first to demonstrate the inhibitory effect of Si on B. setariae in sugarcane, highlighting Si as a promising and environmentally friendly strategy for managing brown stripe disease.

Association Between Acute Kidney Injury Hospital Visits and Environmental Heat Stress at a Nicaraguan Sugarcane Plantation.

BACKGROUND: Mesoamerican sugarcane cutters are at a high risk of chronic kidney disease of non-traditional origin, a disease likely linked to heat-related acute kidney injury (AKI). Studies in general populations have described a positive association between high environmental temperatures and clinically assessed kidney outcomes, but there are no studies in occupational settings. METHOD: We accessed routine records of clinically diagnosed AKI (AKI-CD) and wet bulb globe temperatures (WBGT) at a large Nicaraguan sugarcane plantation and modeled the relationship between these using negative binomial regression. A rest-shade-hydration intervention was gradually enhanced during the study period, and efforts were made to increase the referral of workers with suspected AKI to healthcare. RESULTS: Each 1°C WBGT was associated with an 18% (95% confidence interval [CI]: [4, 33%]) higher AKI-CD rate on the same day and a 14% (95% CI [-5, 37%]) higher rate over a week. AKI-CD rates and severity, and time between symptoms onset and diagnosis decreased during the study period, that is, with increasing rest-shade-hydration intervention. Symptoms and biochemical signs of systemic inflammation were common among AKI-CD cases. DISCUSSION: Occupational heat stress, resulting from heavy work in environmental heat, was associated with a higher rate of clinically diagnosed AKI in a population at risk of CKDnt. Promoting rest-shade-hydration may have contributed to reducing AKI rates during the study period. Occupational health and safety personnel have key roles to play in enforcing rest, shade, and hydration practices, referring workers with suspected AKI to healthcare as well as collecting and analyzing the data needed to support workplace heat stress interventions.

Optimizing the releasing strategy used for the biological control of the sugarcane borer Diatraea saccharalis by Trichogramma galloi with computer modeling and simulation.

One of the challenges in augmentative biological control programs is the definition of releasing strategy for natural enemies, especially when macro-organisms are involved. Important information about the density of insects to be released and frequency of releases usually requires a great number of experiments, which implies time and space that are not always readily available. In order to provide science-based responses for these questions, computational models offer an in silico option to simulate different biocontrol agent releasing scenarios. This allows decision-makers to focus their efforts to more feasible options. The major insect pest in sugarcane crops is the sugarcane borer Diatraea saccharalis, which can be managed using the egg parasitoid Trichogramma galloi. The current strategy consists in releasing 50,000 insects per hectare for each release, in three weekly releases. Here, we present a simulation model to check whether this releasing strategy is optimal against the sugarcane borer. A sensitive analysis revealed that the population of the pest is more affected by the number of releases rather than by the density of parasitoids released. Only the number of releases demonstrated an ability to drive the population curve of the pest towards a negative growth. For example, releasing a total of 600,000 insects per hectare in three releases led to a lower pest control efficacy that releasing only 250,000 insects per hectare in five releases. A higher number of releases covers a wider range of time, increasing the likelihood of releasing parasitoids at the correct time given that the egg stage is short. Based on these results, it is suggested that, if modifications to the releasing strategy are desired, increasing the number of releases from 3 to 5 at weekly intervals is most likely preferable.

Transcriptome and small RNA analysis unveils novel insights into the C4 gene regulation in sugarcane.

MAIN CONCLUSION: This study reveals miRNA indirect regulation of C4 genes in sugarcane through transcription factors, highlighting potential key regulators like SsHAM3a. C4 photosynthesis is crucial for the high productivity and biomass of sugarcane, however, the miRNA regulation of C4 genes in sugarcane remains elusive. We have identified 384 miRNAs along the leaf gradients, including 293 known miRNAs and 91 novel miRNAs. Among these, 86 unique miRNAs exhibited differential expression patterns, and we identified 3511 potential expressed targets of these differentially expressed miRNAs (DEmiRNAs). Analyses using Pearson correlation coefficient (PCC) and Gene Ontology (GO) enrichment revealed that targets of miRNAs with positive correlations are integral to chlorophyll-related photosynthetic processes. In contrast, negatively correlated pairs are primarily associated with metabolic functions. It is worth noting that no C4 genes were predicted as targets of DEmiRNAs. Our application of weighted gene co-expression network analysis (WGCNA) led to a gene regulatory network (GRN) suggesting miRNAs might indirectly regulate C4 genes via transcription factors (TFs). The GRAS TF SsHAM3a emerged as a potential regulator of C4 genes, targeted by miR171y and miR171am, and exhibiting a negative correlation with miRNA expression along the leaf gradient. This study sheds light on the complex involvement of miRNAs in regulating C4 genes, offering a foundation for future research into enhancing sugarcane's photosynthetic efficiency.

Biochar aided priming of carbon and nutrient availability in three soil orders of India.

In recent years biochar (BC) has gained importance for its huge carbon (C) sequestration potential and positive effects on various soil functions. However, there is a paucity of information on the long-term impact of BC on the priming effect and nutrient availability in soil with different properties. This study investigates the effects of BC prepared from rice husk (RBC4, RBC6), sugarcane bagasse (SBC4, SBC6) and mustard stalk (MBC4, MBC6) at 400 and 600 °C on soil C priming and nitrogen (N), phosphorus (P), and potassium (K) availability in an Alfisol, Inceptisol, and Mollisol. BC properties were analyzed, and its decomposition in three soil orders was studied for 290 days in an incubation experiment. Post-incubation, available N, P, and K in soil were estimated. CO2 evolution from BC and soil alone was also studied to determine the direction of priming effect on native soil C. Increasing pyrolysis temperature enhanced pH and EC of most of the BC. The pyrolysis temperature did not show clear trend with respect to priming effect and nutrient availability across feedstock and soil type. MBC6 increased C mineralization in all the soil orders while RBC6 in Alfisol and SBC6 in both Inceptisol and Mollisol demonstrated high negative priming, making them potential amendments for preserving native soil C. Most of the BC showed negative priming of native SOC in long run (290 days) but all these BC enhanced the available N, P, and K in soil. SBC4 enhanced N availability in Alfisol and Inceptisol, RBC4 improved N and P availability in Mollisol and P in Alfisol and MBC6 increased K availability in all the soils. Thus, based on management goals, tailored BC or blending different BC can efficiently improve C sequestration and boost soil fertility.

Transcriptome scale analysis to decode the differential sucrose accumulation mechanisms in sugarcane under the effect of gibberellin.

In the present study, we analyzed GA3 (gibberellin)-treated sugarcane samples at the transcriptomic level to elucidate the differential expression of genes that influence sucrose accumulation. Previous research has suggested that GA3 application can potentially delay sink saturation by enhancing sink strength and demand, enabling the accommodation of more sucrose. To investigate the potential role of GA-induced modification of sink capacity in promoting higher sucrose accumulation, we sought to unravel the differential expression of transcripts and analyze their functional annotation. Several genes homologous to the sugar-phosphate/phosphate translocator, UTP-glucose-1-phosphate uridylyltransferase, and V-ATPases (vacuolar-type H+ ATPase) were identified as potentially associated with the increased sucrose content observed. A differentially expressed transcript was found to be identical to the mRNA of an unknown protein. Homology-based bioinformatics analysis suggested it to be a hydrolase enzyme, which could potentially act as a stimulator of sucrose buildup. The database of differentially expressed transcripts obtained in this study under the influence of GA3 represents a valuable addition to the sugarcane transcriptomics and functional genomics knowledge base.

Inhibition of co-occurring weeds and young sugarcane seedling growth by perennial sugarcane root extract.

Allelopathy is a process whereby a plant directly or indirectly promotes or inhibits growth of surrounding plants. Perennial sugarcane root extracts from various years significantly inhibited Bidens pilosa, Digitaria sanguinalis, sugarcane stem seedlings, and sugarcane tissue-cultured seedlings (P < 0.05), with maximum respective allelopathies of - 0.60, - 0.62, - 0.20, and - 0.29. Allelopathy increased with increasing concentrations for the same-year root extract, and inhibitory effects of the neutral, acidic, and alkaline components of perennial sugarcane root extract from different years were significantly stronger than those of the control for sugarcane stem seedlings (P < 0.05). The results suggest that allelopathic effects of perennial sugarcane root extract vary yearly, acids, esters and phenols could be a main reason for the allelopathic autotoxicity of sugarcane ratoons and depend on the type and content of allelochemicals present, and that allelopathy is influenced by other environmental factors within the rhizosphere such as the presence of old perennial sugarcane roots. This may be a crucial factor contributing to the decline of perennial sugarcane root health.

Transcriptome Analysis Reveals a Diverse Range of Novel Viruses in Australian Sugarcane Soldier Fly (Inopus flavus) Larvae.

In Australia, Soldier flies (Inopus spp.) are economically significant pests of sugarcane that currently lack a viable management strategy. Despite various research efforts, the mechanisms underlying the damage caused by soldier fly larvae remain poorly understood. Our study aims to explore whether this damage is associated with the transmission of plant viruses during larval feeding. We also explore the larval transcriptome to identify any entomopathogenic viruses with the potential to be used as biocontrol agents in future pest management programs. Seven novel virus sequences are identified and characterised using de novo assembly of RNA-Seq data obtained from salivary glands of larvae. The novel virus sequences belong to different virus families and are tentatively named SF-associated anphevirus (SFaAV), SF-associated orthomyxo-like virus (SFaOV), SF-associated narna-like virus (SFaNV), SF-associated partiti-like virus (SFaPV), SF-associated toti-like virus (SFaTV-1 and SFaTV-2) and SF-associated densovirus (SFaDV). These newly identified viruses are more likely insect-associated viruses, as phylogenetic analyses show that they cluster with other insect-specific viruses. Small RNA analysis indicates prominent peaks at both 21 nt and 26-29 nt, suggesting the activation of host siRNA and piwiRNA pathways. Our study helps to improve understanding of the virome of soldier flies and could identify insect viruses for deployment in novel pest management strategies.

Fusarium sacchari hypovirus 1, a Member of Hypoviridae with Virulence Attenuation Capacity in Phytopathogenic Fusarium Species.

In a survey of mycoviruses in Fusarium species that cause sugarcane Pokkah boeng disease, twelve Fusarium strains from three Fusarium species (F. sacchari, F. andiyazi, and F. solani) were found to contain Fusarium sacchari hypovirus 1 (FsHV1), which we reported previously. The genomes of these variants range from 13,966 to 13,983 nucleotides, with 98.6% to 99.9% nucleotide sequence identity and 98.70% to 99.9% protein sequence similarity. Phylogenetic analysis placed these FsHV1 variants within the Alphahypovirus cluster of Hypoviridae. Intriguingly, no clear correlation was found between the geographic origin and host specificity of these viral variants. Additionally, six out of the twelve variants displayed segmental deletions of 1.5 to 1.8 kilobases, suggesting the existence of defective viral dsRNA. The presence of defective viral dsRNA led to a two-thirds reduction in the dsRNA of the wild-type viral genome, yet a tenfold increase in the total viral dsRNA content. To standardize virulence across natural strains, all FsHV1 strains were transferred into a single, virus-free Fusarium recipient strain, FZ06-VF, via mycelial fusion. Strains of Fusarium carrying FsHV1 exhibited suppressed pigment synthesis, diminished microspore production, and a marked decrease in virulence. Inoculation tests revealed varying capacities among different FsHV1 variants to modulate fungal virulence, with the strain harboring the FsHV1-FSA1 showing the lowest virulence, with a disease severity index (DSI) of 3.33, and the FsHV1-FS1 the highest (DSI = 17.66). The identification of highly virulent FsHV1 variants holds promise for the development of biocontrol agents for Pokkah boeng management.

Sugarcane productivity and economic viability in response to planting density.

Planting with higher density in sugarcane is one of the practices used to overcome low productivity. However, this planting material is equivalent to 25% of the total cost of production, being one of the main expenses for cultivation. In this sense, the present work aims to evaluate the productivity and economic viability of sugarcane as a function of planting density. The experiment was carried out at Usina Monte Alegre in the municipality of Mamanguape, Paraíba, Brazil, from March 2021 to January 2022 with the variety RB92579. Seven planting density were studied: T1: 7 gems m-1, T2: 10 gems m-1, T3: 12 gems m-1, T4: 11 gems m-1, T5: 15 gems m-1, T6: 17 gems m-1, T7: 24 gems m-1, in randomized blocks with four replications. Growth, productivity and economic viability were evaluated. The highest productivity of cane and sugar, 77.69 ton ha-1 and 10.390 ton ha-1, respectively, was with planting density of 17 and 24 gems-1. While the minimum productivity of cane (61.313 ton ha-1) and sugar (7.924 ton ha-1) was recorded at sowing density of 7 and 11 gems-1. However, cultivation density with 7 and 10 gems m-1 were the ones that provided the highest profitability around 50%, followed by density of 12, 15 and 17 gems m-1 with an average of 45% profit and 11 and 24 gems m-1 with the lowest proportion of profit on average 38%. The cultivation with 17 gems m-1 of cane provides in cane-plant, variety RB92579, greater productivity with a profit rate of 45%, being the most suitable.