Assessment of energy cane bagasse-derived cellulosic microfiber hydrogels on the growth of potted chili peppers.

Energy cane (Saccharum spp.) bagasse, a type of biomass waste, is often underutilized, burned, or left to dispose of itself. This research aimed to evaluate the potential of converting this bagasse into high-value cellulosic microfiber hydrogels (CMH) for water conservation and potted chili (Capsicum annuum) plant growth. CMH offers a biodegradable alternative to synthetic polyacrylamide (PA) hydrogels and provides the dual benefit of improved water use efficiency and reduced environmental impact due to their ability to naturally break down in the soil. In this study, CMH and PA hydrogels were compared for water retention value (WRV), and reswelling kinetics (RK), as well as their effects on plant height, leaf count, root-to-shoot ratios (R:S ratio), and soil moisture retention. Two versions of CMH, CMH65 and CMH60, were prepared with varying cellulose-chitosan ratios: 65:35 and 60:40, respectively. The hydrogels were tested at four concentrations (0, 0.5, 1.0, and 2.0% w/w) by being mixed in Promix® soil. Observations were recorded over a 16-day period without additional water. Also, the WRV of hydrogels at 240 min and RK (10-180 min) were compared over three swelling-deswelling cycles. The PA hydrogel exhibited higher WRV (exceeding 450%) compared to CMH (45%). However, PA led to reduced plant height, leaf count, and R:S ratio when compared to higher concentrations of CMH65 and CMH60. In general, CMH60 (0.5% and 2%) exhibited superior plant growth. All hydrogels exhibited a significant decrease (p < 0.05) in WRV across successive cycles. Notably, during cycle 2, both CMH65 and CMH60 peaked in WRV at 10 and 20 min, respectively, compared to cycle 1. This study demonstrates the potential of bagasse-derived hydrogels as a value-added product for water conservation and crop growth.

Effect of Irrigation on Sugarcane Morphophysiology in the Brazilian Cerrado.

Since sugarcane is semi-perennial, it has no escape from water stresses in the Brazilian Cerrado, and consequently, drought impacts plant growth and industrial quality. The objective of this study was to evaluate the morphophysiology and quality of the first ratoon of two sugarcane varieties submitted to irrigated and stressed treatments under field conditions. For the biometric characteristics, in general, significant decreases were observed under the stressed treatment for all periods, and only minor differences were detected between the studied cultivars. Physiological parameters decreased under stressed conditions, but to a different extent between the varieties. RB855536 was able to maintain a greater rate of transpiration. Productivity was reduced by 103 t ha-1 for variety RB855536 and 121 t ha-1 for RB867515, compared to plants with full irrigation during the dry period, but cane quality was similar in both genotypes. Measurements of physiological and morphological parameters may prove useful in the rapid identification of genotypes with greater tolerance to abiotic stress.

Insights into Reactive Oxygen Species Production-Scavenging System Involved in Sugarcane Response to Xanthomonas albilineans Infection under Drought Stress.

Plants must adapt to the complex effects of several stressors brought on by global warming, which may result in interaction and superposition effects between diverse stressors. Few reports are available on how drought stress affects Xanthomonas albilineans (Xa) infection in sugarcane (Saccharum spp. hybrids). Drought and leaf scald resistance were identified on 16 sugarcane cultivars using Xa inoculation and soil drought treatments, respectively. Subsequently, four cultivars contrasting to drought and leaf scald resistance were used to explore the mechanisms of drought affecting Xa-sugarcane interaction. Drought stress significantly increased the occurrence of leaf scald and Xa populations in susceptible cultivars but had no obvious effect on resistant cultivars. The ROS bursting and scavenging system was significantly activated in sugarcane in the process of Xa infection, particularly in the resistant cultivars. Compared with Xa infection alone, defense response via the ROS generating and scavenging system was obviously weakened in sugarcane (especially in susceptible cultivars) under Xa infection plus drought stress. Collectively, ROS might play a crucial role involving sugarcane defense against combined effects of Xa infection and drought stress.

ShF5H1 overexpression increases syringyl lignin and improves saccharification in sugarcane leaves.

The agricultural sugarcane residues, bagasse and straws, can be used for second-generation ethanol (2GE) production by the cellulose conversion into glucose (saccharification). However, the lignin content negatively impacts the saccharification process. This polymer is mainly composed of guaiacyl (G), hydroxyphenyl (H), and syringyl (S) units, the latter formed in the ferulate 5-hydroxylase (F5H) branch of the lignin biosynthesis pathway. We have generated transgenic lines overexpressing ShF5H1 under the control of the C4H (cinnamate 4-hydroxylase) rice promoter, which led to a significant increase of up to 160% in the S/G ratio and 63% in the saccharification efficiency in leaves. Nevertheless, the content of lignin was unchanged in this organ. In culms, neither the S/G ratio nor sucrose accumulation was altered, suggesting that ShF5H1 overexpression would not affect first-generation ethanol production. Interestingly, the bagasse showed a significantly higher fiber content. Our results indicate that the tissue-specific manipulation of the biosynthetic branch leading to S unit formation is industrially advantageous and has established a foundation for further studies aiming at refining lignin modifications. Thus, the ShF5H1 overexpression in sugarcane emerges as an efficient strategy to improve 2GE production from straw.

Herbicides in the initial growth and chlorophyll indices of sugarcane in pre-sprouted seedlings.

The aim of the present study was to assess the selectivity of herbicides applied in the pre and post-planting of pre-sprouted seedlings (PSS). The experiment was conducted in a greenhouse, using a completely randomized design, with nine treatments and four repetitions. The IACSP95-5000 cultivar was used. The treatments consisted of herbicides applied in five doses as follows: in pre-planting: sulfentrazone, diclosulam, imazapic, and imazapyr, in post-planting: ethoxysulfuron, halosulfuron, 2,4-D and MSMA, and a control treatment without herbicide. Injury symptoms were assessed at 7, 15, 30, 45, 60, 75, and 90 days after application (DAA), height, diameter, number of tillers, chlorophyll A, B, and total chlorophyll at 30, 60, and 90 DAA, leaf area, shoot and root dry mass at 90 DAA. The post-emergent herbicides were considered selective. Pre-planting herbicides reduced the variables assessed at 90 DAA, observed by linear regression for diclosulam and imazapic, and exponential regression for imazapyr. Treatments with sulfentrazone caused few injury symptoms, with subsequent recovery. In addition, all the variables analyzed were equal to control, with the sulfentrazone considered selective for the IACSP95-5000 cultivar.

Foliar Application of Amino Acids and Nutrients as a Tool to Mitigate Water Stress and Stabilize Sugarcane Yield and Bioenergy Generation.

Extended periods of water stress negatively affect sugarcane crop production. The foliar application of supplements containing specific nutrients and/or organic molecules such as amino acids can improve sugarcane metabolism, stalk and sugar yields, and the quality of the extracted juice. The present study assessed the effectiveness of the foliar application of an abiotic stress protection complement (ASPC) composed of 18 amino acids and 5 macronutrients. The experiments were carried out in the field with two treatments and twelve replicates. The two treatments were no application of ASPC (control) and foliar application of ASPC. The foliar application of ASPC increased the activity of antioxidant enzymes. The Trolox-equivalent antioxidant capacity (DPPH) was higher in ASPC-treated plants than in control plants, reflecting higher antioxidant enzyme activity and lower malondialdehyde (MDA) levels. The level of H2O2 was 11.27 nM g-1 protein in plants treated with ASPC but 23.71 nM g-1 protein in control plants. Moreover, the application of ASPC increased stalk yield and sucrose accumulation, thus increasing the quality of the raw material. By positively stabilizing the cellular redox balance in sugarcane plants, ASPC application also increased energy generation. Therefore, applying ASPC is an effective strategy for relieving water stress while improving crop productivity.

Exopolysaccharide Production and Precipitation Method as a Tool to Study Virulence Factors.

Acidovorax avenae subsp. avenae (Aaa) is the causal agent of red stripe in sugarcane, a disease characterized by two forms: leaf stripe and top rot. Despite the importance of this disease, little is known about Aaa virulence factors (VFs) and their function in the infection process. Among the different array of VFs exerted by phytopathogenic bacteria, exopolysaccharides (EPSs) often confer a survival advantage by protecting the cell against abiotic and biotic stresses, including host defensive factors. They are also main components of the extracellular matrix involved in cell-cell recognition, surface adhesion, and biofilm formation. EPS composition and properties have been well studied for some plant pathogenic bacteria; nevertheless, there is no knowledge about Aaa-EPS. In this work, we describe a simple and reliable method for EPS production, precipitation, and quantification based on cold precipitation after ethanol addition, which will allow to study EPS characteristics of different Aaa strains and to evaluate the association among EPS (e.g., amount, composition, viscosity) and Aaa pathogenicity.

Stem borer herbivory dependent on interactions of sugarcane variety, associated traits, and presence of prior borer damage.

BACKGROUND: Herbivory risk is mediated by plant traits related to nutrition and defense that can vary within a species by genotype and age. Prior herbivore damage accrued by a plant can also interact with these traits to alter future herbivory potential by changing plant quantity or quality. Sugarcane (Saccharum spp.) is a perennial crop where aboveground biomass is harvested annually and with varieties differing in nutrition and defenses, making it conducive to evaluating varietal resistance mechanisms. Using data from 16 sugarcane varieties and 28 years, we assessed damage from the primary pest in Louisiana, the sugarcane borer (Diatraea saccharalis, SCB), relative to variety, crop year (ratoon), plant traits, and incidence of prior herbivory. RESULTS: SCB damage differed among varieties but not crop year, mostly following previously established classifications of SCB resistance, and correlated with select nutritional and defense traits. Within a crop year, the probability of SCB damage increased with prior conspecific damage on the same stalk. However, the strength of this prior damage effect did not match known resistance patterns but still differed with variety. CONCLUSIONS: Interactions of plant variety, traits, and prior pest damage but not age impacted sugarcane borer risk. Borer damage was associated with nutritional traits of fiber and sugar content, but not consistently with defensive traits like high stalk wax or hair density, indicating there may be additional resistance traits or indirect impacts of these traits on predators. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Virulence of entomopathogenic nematodes and their symbiotic bacteria, under laboratory conditions, aiming controlling Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) on sugarcane / Virulência de nematoides entomopatogênicos e suas bactérias simbióticas, sob condições de laboratório, visando controlar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) na cana-de-açúcar

Sugarcane crops Saccharum spp. (Poales: Poaceae) produces different derivatives to the world: sugar, ethanol and bioenergy. Despite the application of pesticides, insect pests still cause economic losses, among these the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causing direct and indirect damage to the plant. This study assess the virulence of three entomopathogenic nematodes (EPNs) species and their symbiont bacteria against the pink sugarcane mealybug, under laboratory conditions. Fourteen treatments represented by control (distilled water), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) and Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) at concentrations of 25, 50, 75 and 100 infective juveniles (IJs)/insect, and the standard chemical product, thiamethoxam, were assayed. In a second experiment, the bacteria Photorhabdus luminescens (Thomas and Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 and Xenorhabdus nematophila (Poinar and Thomas, 1965) (Enterobacterales: Morganellaceae) at 3.0 x 109 cells/ml were assessed for each treatment. Ten replications were stablished, each one counting ten females/mealybugs inside a 10 cm Petri dish, amounting 100 individuals/treatment. All treatments were kept under stable conditions (25±1 ºC, H 70±10%, in the dark). All nematodes species infected S. sacchari. Steinerma rarum (PAM25) provided the highest mortality against the pink sugarcane mealybug (79.25%), followed by H. bacteriophora (HB EN01) (58.25%) and S. carpocapsae (All) (42.50%) (P<0.001). The mortality rate caused by X. szentirmaii, P. luminescens and X. nematophila were 40, 45 and 20%, respectively. Steinerma rarum (PAM25) has conditions to be a potential agent to be incorporate into the integrated pest management in sugarcane.

A cultura da cana-de-açúcar Saccharum spp. (Poales: Poaceae) produz diferentes derivados para o mundo: açúcar, etanol e bioenergia. Apesar da aplicação de pesticidas, os insetos-praga ainda causam prejuízos econômicos, dentre eles a cochonilha rosada da cana-de-açúcar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causando danos diretos e indiretos à planta. Este estudo avaliou a virulência de três espécies de nematoides entomopatogênicos (NEPs) e suas bactérias simbiontes contra a cochonilha rosada da cana-de-açúcar, em condições de laboratório. Quatorze tratamentos representados pelo controle (água destilada), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) e Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) nas concentrações de 25, 50, 75 e 100 juvenis infectantes (JIs)/inseto, e o produto químico padrão, tiametoxam, foram testados. Em um segundo experimento, a bactéria Photorhabdus luminescens (Thomas e Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 e Xenorhabdus nematophila (Poinar e Thomas, 1965) (Enterobacterales: Morganellaceae) em 3,0 x 109 células/ml foram avaliadas para cada tratamento. Dez repetições foram estabelecidas, cada uma contendo dez fêmeas/cochonilhas dentro de uma placa de Petri de 10 cm, totalizando 100 indivíduos/tratamento. Todos os tratamentos foram mantidos em condições estáveis (25±1 ºC, U 70±10%, no escuro). Todas as espécies de nematoides infectaram S. sacchari. Steinerma rarum (PAM25) proporcionou a maior mortalidade contra a cochonilha rosada da cana-de-açúcar (79,25%), seguida por H. bacteriophora (HB EN01) (58,25%) e S. carpocapsae (All) (42,50%) (P<0,001). As taxas de mortalidade causada por X. szentirmaii, P. luminescens e X. nematophila foram de 40, 45 e 20%, respectivamente. Steinerma rarum (PAM25) tem condições de ser um agente potencial a ser incorporado ao manejo integrado de pragas da cana-de-açúcar.

Virulence of entomopathogenic nematodes and their symbiotic bacteria, under laboratory conditions, aiming controlling Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) on sugarcane

Abstract Sugarcane crops Saccharum spp. (Poales: Poaceae) produces different derivatives to the world: sugar, ethanol and bioenergy. Despite the application of pesticides, insect pests still cause economic losses, among these the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causing direct and indirect damage to the plant. This study assess the virulence of three entomopathogenic nematodes (EPNs) species and their symbiont bacteria against the pink sugarcane mealybug, under laboratory conditions. Fourteen treatments represented by control (distilled water), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) and Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) at concentrations of 25, 50, 75 and 100 infective juveniles (IJs)/insect, and the standard chemical product, thiamethoxam, were assayed. In a second experiment, the bacteria Photorhabdus luminescens (Thomas and Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 and Xenorhabdus nematophila (Poinar and Thomas, 1965) (Enterobacterales: Morganellaceae) at 3.0 x 109 cells/ml were assessed for each treatment. Ten replications were stablished, each one counting ten females/mealybugs inside a 10 cm Petri dish, amounting 100 individuals/treatment. All treatments were kept under stable conditions (25±1 ºC, H 70±10%, in the dark). All nematodes species infected S. sacchari. Steinerma rarum (PAM25) provided the highest mortality against the pink sugarcane mealybug (79.25%), followed by H. bacteriophora (HB EN01) (58.25%) and S. carpocapsae (All) (42.50%) (P 0.001). The mortality rate caused by X. szentirmaii, P. luminescens and X. nematophila were 40, 45 and 20%, respectively. Steinerma rarum (PAM25) has conditions to be a potential agent to be incorporate into the integrated pest management in sugarcane.

Resumo A cultura da cana-de-açúcar Saccharum spp. (Poales: Poaceae) produz diferentes derivados para o mundo: açúcar, etanol e bioenergia. Apesar da aplicação de pesticidas, os insetos-praga ainda causam prejuízos econômicos, dentre eles a cochonilha rosada da cana-de-açúcar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causando danos diretos e indiretos à planta. Este estudo avaliou a virulência de três espécies de nematoides entomopatogênicos (NEPs) e suas bactérias simbiontes contra a cochonilha rosada da cana-de-açúcar, em condições de laboratório. Quatorze tratamentos representados pelo controle (água destilada), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) e Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) nas concentrações de 25, 50, 75 e 100 juvenis infectantes (JIs)/inseto, e o produto químico padrão, tiametoxam, foram testados. Em um segundo experimento, a bactéria Photorhabdus luminescens (Thomas e Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 e Xenorhabdus nematophila (Poinar e Thomas, 1965) (Enterobacterales: Morganellaceae) em 3,0 x 109 células/ml foram avaliadas para cada tratamento. Dez repetições foram estabelecidas, cada uma contendo dez fêmeas/cochonilhas dentro de uma placa de Petri de 10 cm, totalizando 100 indivíduos/tratamento. Todos os tratamentos foram mantidos em condições estáveis (25±1 ºC, U 70±10%, no escuro). Todas as espécies de nematoides infectaram S. sacchari. Steinerma rarum (PAM25) proporcionou a maior mortalidade contra a cochonilha rosada da cana-de-açúcar (79,25%), seguida por H. bacteriophora (HB EN01) (58,25%) e S. carpocapsae (All) (42,50%) (P 0,001). As taxas de mortalidade causada por X. szentirmaii, P. luminescens e X. nematophila foram de 40, 45 e 20%, respectivamente. Steinerma rarum (PAM25) tem condições de ser um agente potencial a ser incorporado ao manejo integrado de pragas da cana-de-açúcar.

Yellow Leaf Disease Resistance and Melanaphis sacchari Preference in Commercial Sugarcane Cultivars.

Sugarcane yellow leaf disease (YLD) caused by sugarcane yellow leaf virus (ScYLV) is a major threat for the sugarcane industry worldwide, and the aphid Melanaphis sacchari is its main vector. Breeding programs in Brazil have provided cultivars with intermediate resistance to ScYLV, whereas the incidence of ScYLV has been underestimated partly due to the complexity of YLD symptom expression and identification. Here, we evaluated YLD symptoms in a field assay using eight sugarcane genotypes comprising six well-established commercial high-sucrose cultivars, one biomass yield cultivar, and a susceptible reference under greenhouse conditions, along with estimation of virus titer through RT-qPCR from leaf samples. Additionally, a free-choice bioassay was used to determine the number of aphids feeding on the SCYLV-infected cultivars. Most of the cultivars showed some degree of resistance to YLD, while also revealing positive RT-qPCR results for ScYLV and virus titers with non-significant correlation with YLD severity. The cultivars IACSP01-5503 and IACBIO-266 were similar in terms of aphid preference and ScYLV resistance traits, whereas the least preferred cultivar by M. sacchari, IACSP96-7569, showed intermediate symptoms but similar virus titer to the susceptible reference, SP71-6163. We conclude that current genetic resistance incorporated into sugarcane commercial cultivars does not effectively prevent the spread of ScYLV by its main aphid vector.

Technological Quality of Sugarcane Inoculated with Plant-Growth-Promoting Bacteria and Residual Effect of Phosphorus Rates.

Phosphate fertilization in highly weathered soils has been a major challenge for sugarcane production. The objective of this work was to evaluate the foliar levels of phosphorus (P) and nitrogen (N) and the technological quality and productivity of second ratoon cane as a function of inoculation with plant-growth-promoting bacteria (PGPBs) together with the residual effect of phosphate fertilization. The experiment was carried out at the research and extension farm of Ilha Solteira, state of São Paulo, Brazil. The experiment was designed in a randomized block with three replications in a 5 × 8 factorial scheme. The treatments consisted of five residual doses of phosphorus (0, 45, 90, 135 and 180 kg ha-1 of P2O5, 46% P) applied at planting from the source of triple superphosphate and eight inoculations from three species of PGPB (Azospirillum brasilense, Bacillus subtilis and Pseudomonas fluorescens), applied in single or co-inoculation at the base of stems of sugarcane variety RB92579. Inoculation with PGPBs influenced leaf N concentration, while inoculations with Pseudomonas fluorescens and combinations of bacteria together with the highest doses exerted a positive effect on leaf P concentration. Co-inoculation with A. brasilense + Pseudomonas fluorescens associated with a residual dose of 135 kg ha-1 of P2O5 increased stem productivity by 42%. Thus, it was concluded that inoculations with Pseudomonas fluorescens and their combinations are beneficial for the sugarcane crop, reducing phosphate fertilization and increasing productivity.

Climate Variations in the Low-Latitude Plateau Contribute to Different Sugarcane (Saccharum spp.) Yields and Sugar Contents in China.

In China, the main sugarcane (Saccharum spp.) planting areas can be found in the low-latitude plateau (21° N-25° N, 97° E-106° E), which has most of the natural ecological types. However, there is limited information on the climate conditions of this region and their influence on sugarcane yield and sucrose content. Monthly variations in the main climate factors, namely, average air temperature (AAT), average relative humidity (ARH), average rainfall amount (ARA), and average sunshine duration (ASD), from 2000 to 2019 and sugarcane yield and sucrose content of 26 major sugarcane-producing areas from 2001/2002 to 2018/2019 were collected from the low-latitude plateau in Yunnan for studying the impact of climate variations on sugarcane yield and sucrose content. The results showed that AAT in the mid-growth season had a significant positive correlation with sucrose content (p < 0.05), and AAT in the late-growth season had a very significant positive correlation with sucrose content (p < 0.01). ARH in the mid-growth season had a significant positive correlation with sugarcane yield (p < 0.05). ARA in the early-growth season showed a significant positive correlation with sugarcane yield (p < 0.05). ASD in the late-growth season had a significant positive correlation with sugarcane yield (p < 0.05) and sucrose content (p < 0.01). The rainy and humid sugarcane areas were characterized by high ARA and ARH during the entire growth period, low AAT and ASD in the mid-growth season, and low AAT in the late-growth season, contributing to a high sugarcane yield, but not a high sucrose content. The low temperature and sunshine semi-humid sugarcane areas were characterized by the lowest AAT in the early and middle stages of sugarcane growth, less ASD in the early and middle stages, and less ARA in the early and late stages, which are unfavorable for sugarcane yield and sucrose content. The high temperature and humidity sugarcane areas were characterized by higher AAT and ARA, and moderate ASD during the entire growth period, resulting in good sugarcane growth potential and contributing to the sugarcane yield and sucrose content. The semi-humid and multi-sunshine sugarcane areas were characterized by the lowest ARH in the entire growth period, the lowest ARA in the middle and late seasons, and the longest ASD, contributing to an increase in sucrose content. The humid and sunny areas were characterized by the longest ASD and high ARH in the early and late seasons of sugarcane growth and moderate AAT and ARA during the entire growth season, which are beneficial for high sugarcane yield and sucrose content. Overall, these findings suggest that the sugarcane variety layout should be based on the climate type (of which there are five in the plateau), and corresponding cultivation practices should be used to compensate for the climatic conditions in various growth stages.

Selenium enhances ROS scavenging systems and sugar metabolism increasing growth of sugarcane plants.

Selenium (Se) beneficial effect on plants is related to an increase in nitrogen (N) assimilation and its role as an abiotic stress mitigator by reactive oxygen species (ROS) scavenging enhanced by antioxidant metabolism. This study aimed to evaluate sugarcane (Saccharum spp.) growth, photosynthetic and antioxidant responses, and sugar accumulation in response to Se supply. The experimental design was a factorial scheme 2 × 4: two sugarcane varieties (RB96 6928 and RB86 7515) and four Se application rates (0; 5; 10 and 20 µmol L-1) applied as sodium selenate in the nutrient solution. Leaf Se concentration increased under Se application in both varieties. The enzymes SOD (EC 1.15.1.1) and APX (EC 1.11.1.11) showed increase activities under Se application on variety RB96 6928. Nitrate reductase activity increased in both varieties resulting in the conversion of nitrate into higher total amino acids concentration indicating an enhanced N assimilation. This led to an increased concentration of chlorophylls and carotenoids, increased CO2 assimilation rate, stomatal conductance, and internal CO2 concentration. Selenium provided higher starch accumulation and sugar profiles in leaves boosting plant growth. This study shows valuable information regarding the role of Se on growth, photosynthetic process, and sugar accumulation in sugarcane leaves, which could be used for further field experiments. The application rate of 10 µmol Se L-1 was the most adequate for both varieties studied considering the sugar concentration and plant growth.

Vinegar: A potential source of healthy and functional food with special reference to sugarcane vinegar.

Vinegar is one of the most widely used acidic condiments. Recently, rapid advances have been made in the area of vinegar research. Different types of traditional vinegar are available around the globe and have many applications. Vinegar can be made either naturally, through alcoholic and then acetic acid fermentation, or artificially, in laboratories. Vinegar is the product of acetic acid fermentation of dilute alcoholic solutions, manufactured by a two-step process. The first step is the production of ethanol from a carbohydrate source such as glucose, which is carried out by yeasts. The second step is the oxidation of ethanol to acetic acid, which is carried out by acetic acid bacteria. Acetic acid bacteria are not only producers of certain foods and drinks, such as vinegar, but they can also spoil other products such as wine, beer, soft drinks, and fruits. Various renewable substrates are used for the efficient biological production of acetic acid, including agro and food, dairy, and kitchen wastes. Numerous reports on the health advantages associated with vinegar ingredients have been presented. Fresh sugarcane juice was fermented with wine yeast and LB acetate bacteria to develop a high-quality original sugarcane vinegar beverage. To facilitate the current study, the bibliometric analysis method was adopted to visualize the knowledge map of vinegar research based on literature data. The present review article will help scientists discern the dynamic era of vinegar research and highlight areas for future research.

A Genome-Wide Association Study and Genomic Prediction for Fiber and Sucrose Contents in a Mapping Population of LCP 85-384 Sugarcane.

Sugarcane (Saccharum spp. hybrids) is an economically important crop for both sugar and biofuel industries. Fiber and sucrose contents are the two most critical quantitative traits in sugarcane breeding that require multiple-year and multiple-location evaluations. Marker-assisted selection (MAS) could significantly reduce the time and cost of developing new sugarcane varieties. The objectives of this study were to conduct a genome-wide association study (GWAS) to identify DNA markers associated with fiber and sucrose contents and to perform genomic prediction (GP) for the two traits. Fiber and sucrose data were collected from 237 self-pollinated progenies of LCP 85-384, the most popular Louisiana sugarcane cultivar from 1999 to 2007. The GWAS was performed using 1310 polymorphic DNA marker alleles with three models of TASSEL 5, single marker regression (SMR), general linear model (GLM) and mixed linear model (MLM), and the fixed and random model circulating probability unification (FarmCPU) of R package. The results showed that 13 and 9 markers were associated with fiber and sucrose contents, respectively. The GP was performed by cross-prediction with five models, ridge regression best linear unbiased prediction (rrBLUP), Bayesian ridge regression (BRR), Bayesian A (BA), Bayesian B (BB) and Bayesian least absolute shrinkage and selection operator (BL). The accuracy of GP varied from 55.8% to 58.9% for fiber content and 54.6% to 57.2% for sucrose content. Upon validation, these markers can be applied in MAS and genomic selection (GS) to select superior sugarcane with good fiber and high sucrose contents.

UAV imagery data and machine learning: A driving merger for predictive analysis of qualitative yield in sugarcane.

Predicting sugarcane yield by quality allows stakeholders from research centers to industries to decide on the precise time and place to harvest a product on the field; hence, it can streamline workflow while leveling up the cost-effectiveness of full-scale production. °Brix and Purity can offer significant and reliable indicators of high-quality raw material for industrial processing for food and fuel. However, their analysis in a relevant laboratory can be costly, time-consuming, and not scalable. We, therefore, analyzed whether merging multispectral images and machine learning (ML) algorithms can develop a non-invasive, predictive framework to map canopy reflectance to °Brix and Purity. We acquired multispectral images data of a sugarcane-producing area via unmanned aerial vehicle (UAV) while determining °Brix and analytical Purity from juice in a routine laboratory. We then tested a suite of ML algorithms, namely multiple linear regression (MLR), random forest (RF), decision tree (DT), and support vector machine (SVM) for adequacy and complexity in predicting °Brix and Purity upon single spectral bands, vegetation indices (VIs), and growing degree days (GDD). We obtained evidence for biophysical functions accurately predicting °Brix and Purity. Those can bring at least 80% of adequacy to the modeling. Therefore, our study represents progress in assessing and monitoring sugarcane on an industrial scale. Our insights can offer stakeholders possibilities to develop prescriptive harvesting and resource-effective, high-performance manufacturing lines for by-products.

Identification of QTLs and critical genes related to sugarcane mosaic disease resistance.

Mosaic viral diseases affect sugarcane productivity worldwide. Mining disease resistance-associated molecular markers or genes is a key component of disease resistance breeding programs. In the present study, 285 F1 progeny were produced from a cross between Yuetang 93-159, a moderately resistant variety, and ROC22, a highly susceptible variety. The mosaic disease symptoms of these progenies, with ROC22 as the control, were surveyed by natural infection under 11 different environmental conditions in the field and by artificial infections with a mixed sugarcane mosaic virus (SCMV) and sorghum mosaic virus (SrMV) inoculum. Analysis of consolidated survey data enabled the identification of 29 immune, 55 highly resistant, 70 moderately resistant, 62 susceptible, and 40 highly susceptible progenies. The disease response data and a high-quality SNP genetic map were used in quantitative trait locus (QTL) mapping. The results showed that the correlation coefficients (0.26~0.91) between mosaic disease resistance and test environments were significant (p< 0.001), and that mosaic disease resistance was a highly heritable quantitative trait (H2 = 0.85). Seven mosaic resistance QTLs were located to the SNP genetic map, each QTL accounted for 3.57% ~ 17.10% of the phenotypic variation explained (PVE). Furthermore, 110 pathogen response genes and 69 transcription factors were identified in the QTLs interval. The expression levels of nine genes (Soffic.07G0015370-1P, Soffic.09G0015410-2T, Soffic.09G0016460-1T, Soffic.09G0016460-1P, Soffic.09G0017080-3C, Soffic.09G0018730-3P, Soffic.09G0018730-3C, Soffic.09G0019920-3C and Soffic.03G0019710-2C) were significantly different between resistant and susceptible progenies, indicating their key roles in sugarcane resistance to SCMV and SrMV infection. The seven QTLs and nine genes can provide a certain scientific reference to help sugarcane breeders develop varieties resistant to mosaic diseases.

Genetic and morphological variants of Acidovorax avenae subsp. avenae cause red stripe of sugarcane in China.

Sugarcane (Saccharum spp.) is an important cash crop for production of sugar and bioethanol. Red stripe caused by Acidovorax avenae subsp. avenae (Aaa) is a disease that occurs in numerous sugarcane-growing regions worldwide. In this study, 17 strains of Aaa were isolated from 13 symptomatic leaf samples in China. Nine of these strains produced white-cream colonies on nutrient agar medium while the other eight produced yellow colonies. In pairwise sequence comparisons of the 16S-23S rRNA internally transcribed spacer (ITS), the 17 strains had 98.4-100% nucleotide identity among each other and 98.2-99.5% identity with the reference strain of Aaa (ATCC 19860). Three RFLP patterns based on this ITS sequence were also found among the strains of Aaa obtained in this study. Multilocus sequence typing (MLST) based on five housekeeping genes (ugpB, pilT, lepA, trpB, and gltA) revealed that the strains of Aaa from sugarcane in China and a strain of Aaa (30179) isolated from sorghum in Brazil formed a unique evolutionary subclade. Twenty-four additional strains of Aaa from sugarcane in Argentina and from other crops worldwide were distributed in two other and separate subclades, suggesting that strains of A. avenae from sugarcane are clonal populations with local specificities. Two strains of Aaa from China (CNGX08 forming white-cream colored colonies and CNGD05 forming yellow colonies) induced severe symptoms of red stripe in sugarcane varieties LC07-150 and ZZ8 but differed based on disease incidence in two separate inoculation experiments. Infected plants also exhibited increased salicylic acid (SA) content and transcript expression of gene PR-1, indicating that the SA-mediated signal pathway is involved in the response to infection by Aaa. Consequently, red stripe of sugarcane in China is caused by genetically different strains of Aaa and at least two morphological variants. The impact of these independent variations on epidemics of red stripe remains to be investigated.

Cytogenetic Characterization and Metabolomic Differences of Full-Sib Progenies of Saccharum spp.

Sugarcane smut is a worldwide fungal disease. Disease resistance breeding is the most economical and effective measure to prevent and control sugarcane smut. The cytogenetic characteristics and metabolomic differences of sugarcane F1s are closely related to disease resistance. Zhongzhe 1 and G160 sugarcane from the same parents (ROC25 and Yunzhe89-7) were used; the plants were grown in accordance with the barrel method. When the seedlings had 4-5 leaves, genomic in situ hybridization (GISH) was performed; digoxigenin (DIG)-labeled female parental (ROC25)DNA and biotin-labeled male parental (Yunzhe89-7) DNA were used as probes, and the karyotypes of two hybrids were analyzed. The new sugarcane smut-resistant variety (Zhongzhe 1) and the susceptible variety (G160) derived from the same parent were analyzed via gas chromatography-mass spectrometry technology (GC-MS) to compare the metabolomic differences between them. GISH analysis revealed that the chromosome ploidy number of Zhongzhe 1 sugarcane and G160 sugarcane were 114 and 110, respectively. However, the two contain different numbers of chromosomes from the female (ROC25) and male (Yunzhe89-7) parents. Moreover, 258 significantly changed metabolites were identified in smut-resistant Zhongzhe 1, as compared with the smut-susceptible G160 sugarcane: 56 flavonoids, 52 phenolic acids, 30 lipids, 26 organic acids, 26 amino acids and derivatives, 19 nucleotides and derivatives, 5 alkaloids, 9 terpenoids, and 35 others. Multivariate statistical analysis revealed a distinct difference in metabolic pathways between Zhongzhe 1 sugarcane and G160, and both of these varieties had unique functional metabolites. Differences in chromosome composition may constitute the genetic basis for the difference in resistance to smut disease between Zhongzhe 1 sugarcane and G160 sugarcane, and a high accumulation of flavonoids, lipids, terpenoids and tannins may constitute the basis of resistance to smut disease for the Zhongzhe 1 variety.