Sugar Tech最新文献

Sugar cane, sugar beet, and sweet sorghum are vital crops globally, providing sugar, renewable energy, and biomaterials. However, these crops face significant challenges from climate change and various biotic and abiotic stresses. Advanced genome editing technologies, such as CRISPR/Cas9, TALENs, and prime editing, have emerged as promising tools for developing resilient crop varieties with superior traits. Unlike traditional breeding methods, genome editing allows for precise and targeted modifications to the plant genome, accelerating the breeding process and enabling the creation of crops with enhanced traits. Recent studies have demonstrated the successful application of these technologies in improving sugar crops. For example, CRISPR/Cas9 has been used to modify sugarcane for improved biomass yield, plant architecture, and quality. TALENs have been employed to improve saccharification efficiency in sugarcane without compromising biomass yield. The advancements in genome technologies hold significant promise for addressing the challenges faced by sugar crops and allow researchers to develop crop varieties that are more resilient to climate change. This review provides an overview of the current status of genome editing in sugar crops, focusing on advanced genome editing tools and their potential applications in improving sugar cane, sugar beet, and sweet sorghum for global food security and sustainability.

Dextranase (endo 1 → 6-α-glucan hydrolase; EC 3.2.1.11) enzyme is applied in sugarcane factories to hydrolyze dextran (α-1 → 6-D-glucan) into smaller, more manageable molecules which can improve crystallization rates, reduce crystal elongation problems, and prevent dextran penalties in the raw sugar. The efficiency of the factory application of dextranase depends on the pH, Brix, temperature, retention time, agitation, type, activity and dose of the applied dextranase, and the enzyme/substrate ratio. Reported optimum conditions for the factory application of concentrated dextranase are: Brix < 25%, temperature 50 °C, pre-limed juice pH 5.90, 1:10 working solution of concentrated dextranase up to 5 mg/mL dosage, retention time 10 min, and 39 rpm agitation. Because (i) some factories have < 10 min juice retention time available and (ii) the relatively high cost of adding dextranase, this small study was undertaken to evaluate and predict dextran hydrolysis in sugarcane juice (3950 mg/kg Haze dextran content) following the optimum conditions with ≤ 5 mg/mL of concentrated dextranase (92,330 DU/mL) and retention times ≤ 5 min. For dextranase concentrations of 4 to 80 mg/L, most of the dextran hydrolysis occurred in the first 1 min after which there were diminishing techno-economic returns with an increase in retention time and dextranase concentration. Reactions of ≤ 5 mg/L dextranase in the juice for 1, 2, 3, and 4 min of reaction time were fitted with either linear or polynomial curves and the equations used to calculate the percent hydrolysis of dextran for low dextranase concentrations from 0.5 to 5 mg/mL for 1 to 4 min. At a very low dose of 0.5 mg/L dextranase, little dextran hydrolysis was gained from 1 to 4 min reaction time, i.e., 3.1 to 6.7%. Approximately 18–19% hydrolysis of dextran was gained by adding 1.5 mg/L for 4 min or 2 mg/L for 3 min. Approximately 25% hydrolysis of dextran was gained by adding 2 mg/L enzyme for 4 min or 3 mg/L for 3 min. Adding 4 mg/L or 5 mg/L caused hydrolysis of up to ~ 44 and 51%, respectively, after 4 min.

Sugarcane orange rust, caused by Puccinia kuehnii, was first described in Java/Indonesia at the end of the nineteenth century. The disease was confined to Asia and Oceania before appearing in the Western Hemisphere at the beginning of the twenty-first century. In the Western Hemisphere, orange rust was first observed in Florida in 2007 and subsequently also diagnosed in Africa (Cameroon and Côte d’Ivoire). Although symptoms of the disease were observed in Gabon as early as 2006, the formal molecular identification of the pathogen was never performed. In this study, leaf samples were collected in Gabon in 2022 from four sugarcane varieties displaying typical symptoms of orange rust. The microscopic characteristics of the foliar lesions (uredinia or pustules) and fungal spores taken from these lesions corresponded to the description of P. kuehnii in the literature. DNA was amplified from urediniospores by multiple displacement amplification and used in a PCR assay with primer pair Pk1F/R specific for P. kuehnii. All 12 tested spore samples (three per sugarcane variety) yielded the expected ~ 500 bp DNA fragment and forward sequenced amplicons matched with P. kuehnii in the GenBank database. DNA amplicons from two varieties (FR94129 and Q203) were cloned and sequenced in both directions. The 524–526 nucleotide sequences of eight clones matched at 99.6–100% with sequences of P. kuehnii in the GenBank database. This is the first report of occurrence of P. kuehnii in Gabon based on microscopy and molecular data.

We have investigated CRISPR/Cas9 mediated editing of als genes in sugarcane. To achieve this, two strategies were followed using editing vectors encoding the Cas9 enzyme, one of three specific sgRNAs targeting segments of the sugarcane als gene and three specific ssDNA templates. First, we approached editing the target site through expressing stably integrated editing vectors after biolistic co-delivery into sugarcane calli alongside the specific ssDNA template and an nptII marker for tissue culture selection. Second, we have sought to edit the target site by transiently expressing the editing components CRISPR/Cas9 and sgRNA with an ssDNA template into sugarcane calli. Transgene integration was confirmed using PCR, and target edition was assessed using PCR/RE and sequencing. Stable integration of the pEG_G1 vector was confirmed in four geneticin-selected, independently transformed calli, while the pEG_G2 vector was inserted into one transformed callus. nptII was inserted in all transformants. Sequencing PCR fragments, including the editing site from three transformed calli, reveals distinct 16–19 base deletions of the target fragment including the PAM site required for dsDNA breakage, but not the desired modification of the target codon. Transient-expression experiments resulted in 74 independent putatively transformed calli selected on bispyribac, but the expected mutations were not observed. We have demonstrated that DNA editing occurs in sugarcane after stable integration of editing vectors including Cas9 and sgRNA genes. Editing resulted in base deletions near the target site. Further experiments are required to understand the conditions leading to the editing of the targeted mutation.

This study delves into the sustainable use of bagasse ash (BA) in conjunction with a liquid alkaline activator (LAA) for pavement subgrade construction. The selection of BA is based on its robust chemical composition, including SiO₂, Al₂O₃, Fe₂O₃, and CaO. These chemical compounds and the LAA enhance the properties of black cotton soil (BCS), specifically its California bearing ratio (CBR) and swelling characteristics, such as expansion ratio (ER). The strength and swelling attributes of the BCS were assessed at 7, 14, and 28 days of curing time. BA and LAA were applied to treat the BCS for use as a pavement subgrade construction material. The effectiveness of BA was gauged by examining the soaked CBR and ER of the modified BCS. The CBR value of the specimen exhibits an increase with up to 20% BA content and prolonged curing time. The microstructural analysis of both natural BCS and BCS treated with BA and LAA was conducted using field emission scanning electron microscopy. The CBR values of the natural BCS and treated BCS are used to determine the thickness of the pavement. The designed pavement thickness also prompted calculations for the initial construction cost and carbon dioxide equivalent (CO_2e).