Leaf Scald Disease Research Articles

Microfluidic Encapsulation of DNAs in Liquid Beads for Digital Loop‐Mediated Isothermal Amplification

Digital nucleic acid analysis has emerged as a prominent tool for the detection and absolute quantification of diverse pathogens. Digital loop‐mediated isothermal amplification (dLAMP) offers highly sensitive, specific, time‐efficient, and cost‐effective nucleic acid amplification. However, existing dLAMP techniques face challenges such as droplet merging, reliance on surfactants, restricted partition capacities, and the potential for sample loss during heating. Herein, these issues are addressed by introducing liquid beads for sample partitioning. Compared to microwells, our approach overcomes the limitations of chamber dimensions, enabling the analysis of an unlimited number of digitized targets. Furthermore, our novel approach effectively addresses sample loss and merging during thermal processing and eliminates the need for surfactants. Accurate and reproducible the quantitative detection of the gene cluster XALB1 of leaf scald disease is conducted using dLAMP based on liquid beads to verify its availability. The results demonstrate a high correlation between target concentration and positive signals, indicating the robust performance of our technique. A comparative analysis is then performed between dLAMP using liquid beads and using single droplets. Benchmarking these two techniques highlights the effectiveness of our innovative technique in overcoming existing challenges in dLAMP.

Prospecting and Identification of Fungi Associated with the Rice Leaf Scald Disease in Togo

Leaf scald, caused by Rhynchosporium oryzae, is the third most damaging rice fungal disease worldwide after blast and helminthosporiosis. This study presents the first report of leaf scald on rice in Togo, based on a comprehensive survey of 93 rice plots across 28 out of 39 prefectures. The research aimed to identify, characterize, and test the pathogenicity of fungi associated with leaf scald symptoms, as well as determine the disease's distribution and severity in Togo. Samples were collected, processed in the laboratory, and cultured using blotting paper and potato dextrose agar media. Results revealed that 97,84% of surveyed plots exhibited symptoms related to leaf scald and severity of the disease record were most 5 except two plots which were recorded 9 on the scale of 1 to 9. Fungal isolates were confirmed as R. oryzae through macroscopic and microscopic analysis, adhering to criteria described in existing literature. Growth of mycelium where about 7,5 days in 90 mm petri dish from both paper blotting and PDA medium from initiative culture. Sporus where two or three septa and were obtained after 9 days. Koch's postulates were fulfilled by reproducing leaf scald symptoms using the isolated fungi on the variety IR 841 at 50 days stage. This study contributes valuable insights into the prevalence and characteristics of leaf scald in Togolese rice field.

VirB11, a traffic ATPase, mediated flagella assembly and type IV pilus morphogenesis to control the motility and virulence of Xanthomonas albilineans.

Xanthomonas albilineans (Xal) is a gram-negative bacterial pathogen responsible for developing sugarcane leaf scald disease, which engenders significant economic losses within the sugarcane industry. In the current study, homologous recombination exchange was carried out to induce mutations within the virB/D4-like type IV secretion system (T4SS) genes of Xal. The results revealed that the virB11-deletion mutant (ΔvirB11) exhibited a loss in swimming and twitching motility. Application of transmission electron microscopy analysis further demonstrated that the ΔvirB11 failed to develop flagella formation and type IV pilus morphology and exhibited reduced swarming behaviour and virulence. However, these alterations had no discernible impact on bacterial growth. Comparative transcriptome analysis between the wild-type Xal JG43 and the deletion-mutant ΔvirB11 revealed 123 differentially expressed genes (DEGs), of which 28 and 10 DEGs were notably associated with flagellar assembly and chemotaxis, respectively. In light of these findings, we postulate that virB11 plays an indispensable role in regulating the processes related to motility and chemotaxis in Xal.

Diffusible signal factor (DSF)-mediated quorum sensing modulates swarming in Xanthomonas albilineans.

Xanthomonas spp. are plant pathogens known for significantly impacting crop yields. Among them, Xanthomonas albilineans (Xal) is notable for colonizing the xylem and causing sugarcane leaf scald disease. This study employed homologous recombination to mutate quorum sensing (QS) regulatory genes (rpf) to investigate their role in Xal pathogenicity. Deletions of rpfF (ΔrpfF), rpfC (ΔrpfC), and rpfG (ΔrpfG) led to reduced swarming, growth, and virulence. However, DSF supplementation restored swarming and growth in the ΔrpfF mutant. Deleting rpfC, rpfG, and rpfF also reduced twitching motility and affected Type IV Pilus (T4P) expression. Transcriptomic analysis revealed that ΔrpfF positively regulates flagellar genes. DSF supplementation in ΔrpfF (ΔrpfF-DSF) modulated the expression of flagellar, chemotaxis, and T4P genes. These findings elucidate the DSF-mediated swarming pathway in Xal and provide valuable insights into its regulatory mechanisms.

Field Evaluation of Sugarcane Genotypes for Resistance to Leaf Scald Disease in China

Field Evaluation of Sugarcane Genotypes for Resistance to Leaf Scald Disease in China

Eliminating leaf scald disease in sugarcane: efficacy of hot water and cold soak treatments

Eliminating leaf scald disease in sugarcane: efficacy of hot water and cold soak treatments

Identification of candidate single-nucleotide polymorphisms (SNPs) and genes associated with sugarcane leaf scald disease

Leaf scald, caused by Xanthomonas albilineans, is a severe disease affecting sugarcane worldwide. One of the most practical ways to control it is by developing resistant sugarcane cultivars. It is essential to identify genes associated with the response to leaf scald. A panel of 170 sugarcane genotypes was evaluated for resistance to leaf scald in field conditions for 2 years, followed by a 1-year greenhouse experiment. The phenotypic evaluation data showed a wide continuous distribution, with heritability values ranging from 0.58 to 0.84. Thirteen single nucleotide polymorphisms (SNPs) were identified, significantly associated with leaf scald resistance. Among these, eight were stable across multiple environments and association models. The candidate genes identified and validated based on RNA-seq and qRT-PCR included two genes that encode NB-ARC leucine-rich repeat (LRR)-containing domain disease-resistance protein. These findings provide a basis for developing marker-assisted selection strategies in sugarcane breeding programs.

Molecular, biochemical and metabolomics analyses reveal constitutive and pathogen-induced defense responses of two sugarcane contrasting genotypes against leaf scald disease

Leaf scald caused by the bacteria Xanthomonas albilineans is one of the major concerns to sugarcane production. To breed for resistance, mechanisms underlying plant-pathogen interaction need deeper investigations. Herein, we evaluated sugarcane defense responses against X. albilineans using molecular and biochemical approaches to assess pathogen-triggered ROS, phytohormones and metabolomics in two contrasting sugarcane genotypes from 0.5 to 144 h post-inoculation (hpi). In addition, the infection process was monitored using TaqMan-based quantification of X. albilineans and the disease symptoms were evaluated in both genotypes after 15 d post-inoculation (dpi). The susceptible genotype presented a response to the infection at 0.5 hpi, accumulating defense-related metabolites such as phenolics and flavonoids with no significant defense responses thereafter, resulting in typical symptoms of leaf scald at 15 dpi. The resistant genotype did not respond to the infection at 0.5 hpi but constitutively presented higher levels of salicylic acid and of the same metabolites induced by the infection in the susceptible genotype. Moreover, two subsequent pathogen-induced metabolic responses at 12 and 144 hpi were observed only in the resistant genotype in terms of amino acids, quinic acids, coumarins, polyamines, flavonoids, phenolics and phenylpropanoids together with an increase of hydrogen peroxide, ROS-related genes expression, indole-3-acetic-acid and salicylic acid. Multilevel approaches revealed that constitutive chemical composition and metabolic reprogramming hampers the development of leaf scald at 48 and 72 hpi, reducing the disease symptoms in the resistant genotype at 15 dpi. Phenylpropanoid pathway is suggested as a strong candidate marker for breeding sugarcane resistant to leaf scald.

Genome Organization of Four Brazilian Xanthomonas albilineans Strains Does Not Correlate with Aggressiveness.

An integrative approach combining genomics, transcriptomics, and cell biology is presented to address leaf scald disease, a major problem for the sugarcane industry. To gain insight into the biology of the causal agent, the complete genome sequences of four Brazilian Xanthomonas albilineans strains with differing virulence capabilities are presented and compared to the GPEPC73 reference strain and FJ1. Based on the aggressiveness index, different strains were compared: Xa04 and Xa11 are highly aggressive, Xa26 is intermediate, and Xa21 is the least, while, based on genome structure, Xa04 shares most of its genomic features with Xa26, and Xa11 share most of its genomic features with Xa21. In addition to presenting more clustered regularly interspaced short palindromic repeats (CRISPR) clusters, four more novel prophage insertions are present than the previously sequenced GPEPC73 and FJ1 strains. Incorporating the aggressiveness index and in vitro cell biology into these genome features indicates that disease establishment is not a result of a single determinant factor, as in most other Xanthomonas species. The Brazilian strains lack the previously described plasmids but present more prophage regions. In pairs, the most virulent and the least virulent share unique prophages. In vitro transcriptomics shed light on the 54 most highly expressed genes among the 4 strains compared to ribosomal proteins (RPs), of these, 3 outer membrane proteins. Finally, comparative albicidin inhibition rings and in vitro growth curves of the four strains also do not correlate with pathogenicity. In conclusion, the results disclose that leaf scald disease is not associated with a single shared characteristic between the most or the least pathogenic strains. IMPORTANCE An integrative approach is presented which combines genomics, transcriptomics, and cell biology to address leaf scald disease. The results presented here disclose that the disease is not associated with a single shared characteristic between the most pathogenic strains or a unique genomic pattern. Sequence data from four Brazilian strains are presented that differ in pathogenicity index: Xa04 and Xa11 are highly virulent, Xa26 is intermediate, and Xa21 is the least pathogenic strain, while, based on genome structure, Xa04 shares with Xa26, and Xa11 shares with X21 most of the genome features. Other than presenting more CRISPR clusters and prophages than the previously sequenced strains, the integration of aggressiveness and cell biology points out that disease establishment is not a result of a single determinant factor as in other xanthomonads.

Farmers’ Efficiency in Using Selected Pesticides for Controlling Rice Pests

Farmers’ efficiency in using pesticides depends on using recommended doses. The research was conducted to determine farmers’ efficiency in using selected pesticides for controlling rice pests and explore the contribution of selected characteristics of the farmers to their efficiency in using selected pesticides for controlling rice pests. Data were collected from randomly selected 252 Common Interest Group (CIG) Member rice farmers of three selected unions of three selected upazillas of Brahmanbaria district of Bangladesh with the help of a pre-tested interview schedule during the period from 01 August 2022 to 30 November 2022. Findings revealed that 38.97% farmers were the efficient users of recommended doses and rest 61.03% farmers had lower to moderate efficiency in using pesticides for controlling rice pests. Based on descending order of Standardized Use Efficiency Index, ‘Gola 80 EC for killing rice bug’ ranked 1st followed by ‘Amistar Top 325 SC for controlling sheath blight disease’, and ‘Thiovit 80 WG for controlling leaf scald disease’. Regression analysis indicated that ‘knowledge on pesticides’, ‘rice farming experience’, ‘extension contacts’, ‘attitude towards use of pesticides’, ‘rice farming area’, and ‘pre-cautions for using pesticides’ of the farmers had significant positive contribution to their efficiency in using selected pesticides for controlling rice pests. Agricultural advisory service providing organizations should increasing contact with the farmers having lower farming experience, lower farming area to increase their knowledge for taking necessary pre-cautions and to form favourable attitude towards judicious and efficient use of pesticides.

Nano-selenium enhances sugarcane resistance to Xanthomonas albilineans infection and improvement of juice quality

Selenium is an important trace element that is beneficial to human health and can enhance plant resistance and crop quality. The occurrence of up-to-date nanotechnology greatly promotes the beneficial efficiency of this trace element on crops. The discovery of nano-Se increased the crop quality and reduced plant disease in different plant. In this study, we reduced sugarcane leaf scald disease incidence by exogenously spraying different concentrations (5 mg/L and 10 mg/L) of nano-Se. Additional studies revealed that spraying of nano-Se reduced reactive oxygen species (ROS) and H2O2 accumulation, and increased antioxidant enzyme activities in sugarcane. The nano-selenium treatments also increased the content of jasmonic acid (JA) and the expression of JA pathway genes. Furthermore, we also found that use nano-Se treatment in an appropriate way can enhance the quality of cane juice. The brix of the cane juice of the selenium-enriched treatment was significantly higher than that of the control group, which was 10.98% and 20.81% higher than that of the CK group, respectively. Meanwhile, the content of certain beneficial amino acids was increased, with the highest being 3.9 times higher than the control. Taken together, our findings inferred that nano-Se could act as a potential eco-fungicide to protect sugarcane from can be used as a potential ecological bactericide to protect sugarcane from Xanthomonas albilineans infections, and improve sugarcane quality. The results arising from this study not only introduces an ecological method to control X. albilineans, but also provides a deep insight into this trace elements for improving juice quality.

Exploration of Botanicals Against Microdochium Oryzae, Causal Agent of Leaf Scald Disease of Rice

Leaf scald disease, caused by the fungus Microdochium oryzae, is a devastating and widespread disease of rice. In India, the disease has been linked to yield reductions of up to 23.4%. Aqueous extracts of Acorus calamus, Azadirachta indica, Allium sativum, Sapindus mukorossi, Annona reticulate, Lanatana camara, and Ocimum sanctum at 10% concentration were tested in vitro against Microdochium oryzae. According to the findings, Azadirachta indica extract (71.11%) and Sapindus mukorossi extract (59.0%) were the most efficient phyto-extracts for reducing M. oryzae mycelial growth and were statistically superior to other phyto-extracts. Allium sativum extract ranked in third position in terms of suppressing mycelial growth (47.43%). Ocimum sanctum (39.97%) and Annona reticulate (34.44%), the last two botanicals, were the least effective in preventing M. oryzae mycelial growth. These plant extracts can thus be utilized to combat the rice leaf scalddisease.

Synergistic Effects of Organosilicon and Cu(OH)2 in Controlling Sugarcane Leaf Scald Disease.

Sugarcane leaf scald is a systemic disease caused by Xanthomonas albilineans that limits sugarcane yield and quality. Previous research has shown that exogenous application of copper hydroxide to plants is effective in controlling this disease. However, long-term bactericide use causes serious "3R" problems: resistance, resurgence, and residue. It is therefore urgent to discover new methods for the improvement of bactericide efficiency and efficacy. In the present study, disease index values for leaf scald were measured in sugarcane seedlings over time to determine the effects of different concentrations of copper hydroxide, types of silicon additive, and treatment timing after inoculation with X. albilineans on controlling sugarcane leaf scald disease. Our results show copper hydroxide mixed with organosilicon additive could improve the bactericide efficiency and efficacy and reduce the growth of pathogenic bacteria, even at a reduced concentration in both laboratory and field conditions. This study provides an important practical model for controlling sugarcane leaf scald disease by reducing the concentration of bactericide and increasing its efficacy in sugarcane fields.

Advances in albicidin

Xanthomonas albilineans (Ashby) Downson is a quarantine pest for importing plants to China that causes leaf scald bacterial disease on sugarcane. X. albilineans produces a potent phytotoxin/antibiotic called albicidin. As a pathogenic factor, albicidin causes typical white leaf stripes by inhibiting plastid DNA gyrase and disturbing chloroplast differentiation. Meanwhile, the antibacterial activity of albicidin gives X. albilineans a competitive advantage against rival bacteria during their colonization. Furthermore, albicidin has a rapid bactericidal activity against a variety of Gram-positive and Gram-negative pathogenic bacteria of human species at nanomolar concentrations, making it a potential antimicrobial drug for clinical application. This article reviews the advances of albicidin from the aspects of its molecular structure, traditional extraction methods, mechanism of action, biosynthetic genes and processes, chemical synthesis method and improvement, in order to provide insights into the prevention and treatment of the sugarcane leaf scald disease, and the development of new antibiotics.

Virulence factors analysis of native isolates of Xanthomonas albilineans and Xanthomonas sacchari from Tucumán, Argentina, reveals differences in pathogenic strategies

AbstractXanthomonas albilineans (Xa) and X. sacchari (Xs) are both sugarcane pathogens. Xa is the causal agent of leaf scald disease, but there is limited information about the pathogenicity of Xs. The aim of this work was to study virulence factors of native strains of Xa (Xa32, Xa33, and XaM6) and Xs (Xs14 and Xs15) previously isolated from sugarcane with leaf scald symptoms, to gain insight into the biology of each microorganism. We analysed epiphytic survival, sensitivity to oxidative stress, extracellular degradative enzymes, cell motilities, exopolysaccharide (EPS) characteristics, cell adhesion, biofilm development, and control of stomatal regulation of the five strains. We observed that each species presented similar phenotypes for every factor analysed. Xa strains appeared to be more sensitive to oxidative stress and presented lower epiphytic survival than Xs. All strains presented endoglucanase activity; however, we could only detect protease and amylase activities in Xs strains. Swimming and sliding were higher in Xs, but twitching was variable among species. We also observed that only Xs strains produced a xanthan‐like EPS, presented a strong cell adhesion, and structured biofilm. We detected some intraspecific variations showing that higher amounts of EPS produced by Xs14 correlated with its higher sliding motility and its homogenous and more adhesive biofilm. In addition, EPSs of Xs14 and Xs15 presented differences in strand height and acetyl percentage. Finally, we found that strains of both species were able to interfere with stomatal aperture mechanism. All these differences could influence the colonization strategies and/or disease progression in each species.

Naked eye evaluation and quantitative detection of the sugarcane leaf scald pathogen,

Sugarcane leaf scald caused by the bacterium Xanthomonas albilineans is a major disease of sugarcane worldwide. Whereas erratic symptoms make phenotypic detection challenging, molecular methods require expensive instruments and labour, and longer sample-to-answer times. We report a novel method for detection of X. albilineans DNA in sugarcane xylem sap. The method involves (i) boiling lysis-based DNA extraction from sugarcane sap; (ii) magnetic purification of target sequences directly from the lysate through use of magnetic bead-bound capture probes; and (iii) DNA sandwich hybridisation platform for HRP/TMB/H2O2 reaction-based naked eye visualisation and electrochemical detection of the target. The method is sensitive (limit of detection 100 fM) and reproducible (relative standard deviation <7%) with linear dynamic range 100 fM–1 nM (R2 = 0.99). The method was tested on a range of sugarcane cultivars of known resistance ratings (susceptible, intermediate resistant, and resistant) for leaf scald disease from an inoculated field trial. Detection levels agreed with the resistance rating of cultivars tested. In addition, qPCR results strongly correlated with our assay (r = 0.91–0.99, P < 0.01) and cultivar resistance rating. We believe that our assay could be useful for rapid screening as well as sensitive quantification of target pathogen DNA in infected sugarcane plants.

First report of Xanthomonas albilineans causing leaf scald on two chewing cane clones in Zhejiang province, China.

In recent years, outbreaks of leaf scald have been reported in two chewing cane clones "Guangdong Huangpi" and "Taoshang Guozhe" in Zhejiang province, China. From May to July 2019, we collected 11 and 13 leaf or stalk samples from symptomatic "Guangdong Huangpi" from four farms in Wenling and "Taoshang Guozhe" clones from three farms in Ruian, Zhejiang province, respectively. Leaves in young plants exhibited white pencil-line streaks (Supplement Fig. 1A & 1D) as well as partial or complete chlorosis of the leaf blade (Supplement Fig. 1B & 1E). Internal symptoms included an orange-red discoloration of the vascular bundles at the basal nodes of the stalk and discoloration extension into the internodes (Supplement Fig. 1C & 1F). Leaf and stalk tissues were used for bacterial isolation and purification on XAS medium, which is selective for Xanthomonas albilineans (Davis et al. 1994), using the streak plate method to obtain 24 isolates (Lin et al. 2018). Circular, convex, smooth, shiny and yellow colonies were isolated from all the samples. The pathogenicity of two isolates, XaCN30 from "Guangdong Huangpi" and XaCN43 from "Taoshang Guozhe", was confirmed with Koch's postulates according to the protocol reported by Lin et al. (2018). The incidences of diseased plants (56% and 63%) were observed in individual host clones at 28 d post-inoculation with isolates XaCN30 and XaCN43, respectively. Furthermore, all isolates were confirmed as X. albilineans via molecular methods. PCR amplification was conducted for all 24 isolates using the primer pairs XgyrB1F/XgyrB1R2 (Ntambo et al. 2019) and XAF1/XAR1 (Wang et al. 1999), which targeting the gyrB (encoding the b subunit of the DNA gyrase) and abc (encoding an ABC transporter) genes, and generating 904 bp and 608 bp amplicons, respectively. The PCR fragments were cloned into the pMD19-T vector (TaKaRa, Dalian, China). For each isolate, three single colonies of transformed Escherichia coli DH5α carrying targeted fragment were sequenced. These sequences were deposited into the GenBank with accession no. MT776053-MT776059 and MT776061-MT776077 for gyrB gene and MT776098-MT776104 and MT776106-MT776122 for abc gene. Based on the two concatenated DNA sequences of our 24 isolates, compared with 27 previously reported X. albilineans isolates obtained from the GenBank database, pairwise sequence identity analysis revealed that all 24 isolates from Zhejiang province had 99.4-100% identity with each other, 99.6-100% identity with 14 published domestic isolates, and 98.3-100% identity with 13 foreign isolates. Furthermore, phylogenetic analysis with MEGA 7.0 (Kumar et al. 2016) showed that the isolates from Zhejiang province clustered into two distinct groups (Supplement Fig. 2). One group consisted of 25 Chinese isolates (including all 11 isolates from Wenling) along with four isolates from the French West Indies (GPE PC73, GPE PC17, GPE PC86, and MTQ032), and one isolate from the USA (XaFL07-1), which were assigned to pulsed-field gel electrophoresis (PFGE) group B (Davis et al. 1997; Pieretti et al. 2012). A putative group was also proposed, which included all 13 isolates from Ruian, indicating that isolates from Ruian are distinct from the isolates isolated from other Chinese sugarcane-planting areas, including Wenling. We conclude that leaf scald disease in local clones of chewing cane are caused by X. albilineans in Zhejiang province in China, which will be helpful for leaf scald management in chewing cane, a cash crop.

Genome-wide identification and characterization of DCL, AGO and RDR gene families in Saccharum spontaneum

RNA silencing is a conserved mechanism in eukaryotic organisms to regulate gene expression. Argonaute (AGO), Dicer-like (DCL) and RNA-dependent RNA polymerase (RDR) proteins are critical components of RNA silencing, but how these gene families’ functions in sugarcane were largely unknown. Most stress-resistance genes in modern sugarcane cultivars (Saccharum spp.) were originated from wild species of Saccharum, for example S. spontaneum. Here, we used genome-wide analysis and a phylogenetic approach to identify four DCL, 21 AGO and 11 RDR genes in the S. spontaneum genome (termed SsDCL, SsAGO and SsRDR, respectively). Several genes, particularly some of the SsAGOs, appeared to have undergone tandem or segmental duplications events. RNA-sequencing data revealed that four SsAGO genes (SsAGO18c, SsAGO18b, SsAGO10e and SsAGO6b) and three SsRDR genes (SsRDR2b, SsRDR2d and SsRDR3) tended to have preferential expression in stem tissue, while SsRDR5 was preferentially expressed in leaves. qRT-PCR analysis showed that SsAGO10c, SsDCL2 and SsRDR6b expressions were strongly upregulated, whereas that of SsAGO18b, SsRDR1a, SsRDR2b/2d and SsRDR5 was significantly depressed in S. spontaneum plants exposed to PEG-induced dehydration stress or infected with Xanthomonas albilineans, causal agent of leaf scald disease of sugarcane, suggesting that these genes play important roles in responses of S. spontaneum to biotic and abiotic stresses.

Sugarcane Leaf Scald Disease in Côte d'Ivoire: Pathogenicity and Biocontrol of Xanthomonas albilineans Isolates

Aims: The present investigations describes bactericidal potential of essential oil for management of Xanthomonas albilineans (Ashby. 1929) Dowson 1943, pathogen responsible for sugarcane Leaf scald disease in Côte d'Ivoire.
 Study Design: the study was conducted at the Ferké 1 sugar mill and the Laboratory of Plant Physiology of Felix Houphouët BOIGNY University.
 Methodology: Diseased leaves specimens showing signs of X. albilineans presence were collected from sugarcane industrial plantations in Côte d'Ivoire. Pathogenicity was confirmed by observing Koch’s postulates under semi-controlled conditions. Asymptomatic leaves, obtained after 60 days of culture, were inoculated at three points by infiltration with bacterial suspension calibrated at 108 bacteria/ml. Apparition of small tan-brown necrotic lesions on the leaf blade, parallel to the veins and prolonged to the ends by a discolored vascular bundle confirmed that disease is caused by Xanthomonas albilineans. Three essential oils of aromatic plants whose antibacterial properties are recognized were used at 100; 300; 500; 1000 and 2000 ppm in comparison with Callicuivre (56% copper oxychloride) used as reference product.
 Results: The aqueous solutions based on these essential oils induced an inhibition zone of bacterial growth proportional to the dose applied and the incubation period. Thus, on day 5 of incubation, the essential oil solution of Ocimum gratissimum L. at 100 ppm induced an average inhibition zone diameter not significantly different from the one induced by the Cymbopogon citratus (DC.) Stapf solution at 300 ppm and the one of copper oxychloride at 1000 ppm. At 1000 ppm, Zingiber officinale Roscoe, Cymbopogon citratus (DC.) Stapf and Ocimum gratissimum L essential oils induced equivalent inhibition rates (6 mm) that were higher than that of the control (3.5 mm).
 Conclusion: sugarcane varieties cultivated at the Ferké 1 sugar mill complex, despite the selection for resistance are threatened by Leaf Scald Disease, which is significantly expressed on variety R585. Cymbopogon citratus (DC.) Stapf and Ocimum gratissimum L oils have the strongest antibacterial activity and may be useful to control Leaf Scald Disease.

Albicidin, a potent DNA gyrase inhibitor with clinical potential.

The emergence of multiple antibiotic-resistant bacteria is a serious global problem which requires the development of new effective antimicrobial therapeutics. Albicidin produced by the sugarcane pathogen Xanthomonas albilineans is a potent DNA gyrase inhibitor with inhibitory effects significantly better than most DNA gyrase inhibitors. Albicidin acts primarily by inhibiting the religation of the cleaved DNA intermediate during the gyrase catalytic sequence similar to quinolones. The clinical realization of albicidin has been hampered by limited production and its unsolved structure. In this review, the relationship between albicidin and sugarcane leaf-scald disease is described. Furthermore, the biosynthesis and resistance mechanisms of albicidin are discussed. Finally, recent efforts to solve the structure and produce albicidin in a heterologous host and chemically are summarized.