Innovative Chitosan–Caffeic Acid Phenyl Ester Nanocomposite as a Sustainable Tool against Charcoal Rot Disease of Sunflower in Egypt

Commercially available natural inhibitors of trichothecene production in Fusarium graminearum: A strategy to manage Fusarium head blight of wheat

Charcoal rot disease, a root and stem disease caused by the soil-borne fungus Macrophomina phaseolina (Tassi) Goid., is a major biotic stress that limits sorghum productivity worldwide. Charcoal rot resistance-related parameters, e.g., pre-emergence damping-off%, post-emergence damping-off%, charcoal rot disease severity, and plant survival rates, were measured in a structured sorghum population consisting of 107 landraces. Analysis of variance of charcoal rot resistance-related parameters revealed significant variations in the response to M. phaseolina infection within evaluated accessions. Continuous phenotypic variations for resistance-related parameters were observed indicating a quantitative inheritance of resistance. The population was genotyped using 181 simple sequence repeat (SSR) markers. Association analysis identified 13 markers significantly associated with quantitative trait genes (QTLs) conferring resistance to charcoal rot disease with an R2 value ranging between 9.47 to 18.87%, nine of which are environment-specific loci. Several QTL-linked markers are significantly associated with more than one resistance-related parameter, suggesting that those QTLs might contain genes involved in the plant defense response. In silico analysis of four novel major QTLs identified 11 putative gene homologs that could be considered as candidate genes for resistance against charcoal rot disease. Cluster analysis using the genotypic data of 181 SSR markers from 107 sorghum accessions identified 12 main clusters. The results provide a basis for further functional characterization of charcoal rot disease resistance or defense genes in sorghum and for further dissection of their molecular mechanisms.

A field trial was conducted at Mallawi Agricultural Research Station, Minia Governorate, ARC, during 2016 and 2017 seasons in a high naturally infested field with charcoal rot and wilt diseases complex, as well as under artificially infestation with charcoal rot and wilt pathogens i.e. Macrophomina phaseolina and Fusarium oxysporum, respectively. The aim of this working to study the effect of intercropping guar with sesame at three planting densities of 100, 67 and 50% from sole guar and number of once and twice to reduce charcoal rot and wilt diseases complex, and yield and yield components of both crops. All intercropping patterns were significantly decreased disease incidence of charcoal rot and wilt diseases compared to the sole sesame under field and pots conditions. The intercropping 100% Sesame + 100% guar was the best pattern to reduce the incidence of charcoal rot & wilt disease complex in both seasons and pots experiment. Sesame seed yield/fad with guar at 50% plant density was increased by 32.66, 23.27% and 28.51, 18.58% than those of guar at of 100% and 67% in the 1 st and 2 nd, seasons, respectively. The highest value of total fresh yield/fad (ton) and total dry yield/fad (ton) of guar with sesame at intercropping pattern 100% guar were 5.91, 0.79 and 6.69, 0.69 ton/fad in the first and second seasons, respectively. Intercropping 50% guar with sesame and one cut guar recorded the highest values for LER, net return and MAI (monetary advantage index) in both seasons. Meanwhile, the lowest net return was recorded for intercropping 100% with two cuts of guar. Our study concluded that intercropping crop guar can be used for the protection of sesame charcoal- rot and wilt disease complex and produced greater seed yield than either crops grown alone.

harcoal rot (Macrophomina phaseolina (Tassi) Goidanich) of soybean (Glycine max (L.) Merr.) is a disease of economic significance throughout the world.Pathogenicity of 14 isolates of Macrophomina phaseolina was tested on soybean cv.Giza 21 under greenhouse conditions.They capable to infect soybean plants caused charcoal rot on the basil stem with various degrees of diseases severity.Isolate S13 caused the highest charcoal rot severity (60%) followed by isolates S11 and S8 (57.9 and 56.3 %, respectively).The positive effect of two inducer chemicals, i.e riboflavin (vitamin B2) and.thiamine (vitamin B1) on the induction of systemic resistance in soybean against charcoal rot disease as well as biochemical changes associated with these treatments in soybean plants was recorded.Under greenhouse conditions, the dose effect of 0.1 to 15 mM riboflavin and thiamine showed that 2.5 mM of riboflavin and 5 mM of thiamine was sufficient for maximum induction of resistance; higher concentration did not increase the effect.On the other hand, plants treated with riboflavin and thiamine and inoculated with pathogen grow higher than plants treated with sterilized distilled water (SDW) and inoculated with pathogen, while increased fresh and dry weight of soybean plants.At 10 mM concentration of riboflavin and thiamin recorded the highest dry and fresh weights.In time course observation, it was observed that riboflavin and thiamine treated soybean plants were inducing resistance one day after treatment and reached its maximum level from 5 to 7 days in case of riboflavin and 6-8 days in case of thiamine and then decreased.Under field conditions, the percentages of damping-off, root rot and/or charcoal rot severity were significantly reduced due to soaking the seeds in any of riboflavin and thiamine before sowing in both trial seasons (2008-2009 and 2009-2010).Also, these treatments significantly increased nodule numbers plant -1 , fresh and dry weight of nodules plant -1 in both experimental seasons.Generally, thiamine gave the best results in most cases under greenhouse and field conditions.In physiological studies, activity of defense-related enzymes, including peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, pathogenesis related (PR) protein (chitinase), were increased in inoculated and non-inoculated plants treated with the thiamine and riboflavin individually, during the experimental period.In general, activity of these enzymes begins to accumulate after two days of treatment and reached maximum levels at 8, 6, 8 and 8 days for PO, PPO, PAL and chitanase, respectively, then the activities of these C

Sunflower (Helianthus annuus L.), a member of the Asteraceae, is one of the major oilseed crops around the world. Charcoal rot caused by Macrophomina phaseolina (Tassi) Goid is the most damaging disease of sunflowers globally. Fungicides are mostly used to control charcoal rot; however, these cause environmental pollution and pose adverse effects on the ecosystem. Therefore, ecofriendly management options are inevitable for the management of charcoal rot disease. Plant mineral nutrition, the use of plant growth-promoting rhizobacteria and biochar have recently been manipulated for the management of different plant diseases. However, the interactive effects of all these treatments have rarely been tested on charcoal rot suppression in sunflowers. This study assessed the influence of sulfur (0 and 2.25 mg/kg) combined with farmyard manure biochar (2%), NPK (20:20:20 mg/kg) and three different plant growth-promoting rhizobacteria (PGPR) strains on the charcoal rot suppression growth, yield, biochemistry and physiology of sunflower. The PGPR strains included in the study were Bacillus sp. strain MR-1/2 (regarded as PGPR1), Achromobacter sp. strain FB-14 (regarded as PGPR2) and Planomicrobium sp. strain MSSA-10 (regarded as PGPR3). The charcoal rot infestation was induced by inoculating the soil with M. phaseolina, and the impacts of the different treatments were studied on the disease infestation, growth, yield, biochemistry and physiology of sunflowers under 0 and 2.25-mg/kg S application. The results revealed that farmyard manure biochar and Planomicrobium sp. strain MSSA-10 in combination with 2.25-mg/kg S proved effective for the management of charcoal rot disease through regulating the antioxidant enzymes’ activities and strengthening the immune system of sunflower plants. The studied health markers (total chlorophyll content and carotenoids) and stress markers (total protein content, catalase and peroxidase) were significantly altered by the applied treatments under 0 and 2.25-mg/kg S applications. The findings of the experiment indicated that both farmyard manure biochar and Planomicrobium sp. strain MSSA-10, combined with 2.25-mg/kg S, could be used to enhance the crop yield and manage charcoal rot disease in sunflowers. Farmyard manure biochar and Planomicrobium sp. strain MSSA-10 are an easy-to-apply, cost-effective, ecofriendly and sustainable option for the management of charcoal rot disease in sunflowers.

This study was carried out in augmented design during rabi 2021 (November‒May) at Agriculture research station, Hagari, Karnataka, India to identify the charcoal rot resistant mutant line. Total 200 mutants and 7 checks were used to study the charcoal rot resistance in the present experiment. Charcoal rot is a major disease in the dry sorghum-growing regions of Asia, Africa, Americas and Australia. Charcoal rot disease is caused by Macrophomina phaseolina (Tassi) Goid. It appears in severe form on the improved varieties in hot dry weather with soil moisture stress. The process of mutation is recognized as one of the driving forces of evolution. Induced mutation breeding is a relatively quick method of creating variability in quantitatively inherited traits between plants. The parameters used in charcoal rot studies were lodging per cent, mean number of nodes crossed, mean length of spread and Charcoal rot index (CRI). The screening results revealed that 66 mutant lines shown moderate resistant reaction compared to the resistant check DSV-4 (0.5) and E-36-1 (0.27), among them eight mutants had exact only one node crossed by the pathogen. These mutant lines exhibited comparatively lowest number of mean nodes crossed. 84 mutant lines shown moderate resistant response to charcoal rot index trait. These resistant lines can be used for further confirmation and also for future resistant breeding programme.

Sunflower (Helianthus annuus L.) is considered as one of the most important oilseed crops in Egypt and worldwide. It is being infected with many pathogens, among these pathogens Macrophomina phaseolina (Tassi) Goid, the causal agent of charcoal rot is the most prevalent one, and responsible for severe economic losses on sunflower production. Fourteen isolates of M. phaseolina were collected from naturally infected sunflower plants. Pathogenicity tests revealed that tested isolates varied significantly in their pathogenic capabilities. But all of the tested isolates were pathogenic and incited the symptoms of pre- and post-emergence damping-off as well as symptoms of charcoal rot. In this study, antagonistic capabilities of 26 isolates of Trichoderma spp. were investigated under both laboratory and greenhouse conditions. In vitro, T. harzianum (T8) and T. hamatum (T12) proved to have high antagonistic capability against M. phaseolina fungus with inhibition percentage of 62.13% and 61.33%, respectively. Furthermore, these two isolates proved to have a high ability to control charcoal rot disease. Data of greenhouse experiments showed that application of T. harzianum (T8) and T. hamatum (T12) decreased charcoal rot disease severity by 30.33 and 24.16% respectively. Time of application played a critical role to increase the efficiency of Trichoderma spp. to control charcoal rot. In this experiment Trichoderma was implemented into soil at different application dates to study the effect of application date on the efficiency of bioagents to control charcoal rot. Results of this experiment showed that the highest reduction in disease severity occurred when T. harzianum (T8) was applied seven days before soil infestations with M. phaseolina (38.40%). Data also demonstrated that application of either T. harzianum or T. hamatum led to significant increases in the percentage of survival plants with 72.5% and 68.33%, respectively. This study suggests using Trichoderma spp could be an efficient method to control sunflower charcoal rot.

Induced resistance and control of charcoal rot in <i>Cicer arietinum</i> (chickpea) by <i>Pseudomonas fluorescens</i>

Biosynthesized silver nanoparticles using Trichoderma harzianum reduce charcoal rot disease in bean

Aim. To determine a set of sunfl ower pathogens and their variability infl uenced by hydrothermal conditions of the crop growing season. Methods. Over the period of 2007–2016, due to phytosanitary monitoring of breeding crops of the scientifi c crop rotation of the Plant Production Institute named after V.Ya. Yuriev of NAAS, the prevalence degree, development intensity and variability of sunfl ower diseases in the Eastern Forest-Steppe of Ukraine were estimated. The hydrothermal coeffi cient (HTC) is presented for the sunfl ower growing season and by developmental phases of the crop. Results. Phomopsis blight (Phomopsis/Diaporthe helianthi Munt.- Cvet. et al.), gray mold (Botrytis cinerea Pers.), dry rot (Rhizopus sp.), charcoal rot (Sclerotium bataticolaTaub), and downy mildew (Plasmopara helianthi Novot. f. helianthi) were the most common diseases on sunfl ower in the Eastern Forest-Steppe of Ukraine in 2007–2016. The weather conditions of 2007–2016 considerably varied and were characterized by fl uctuations in the hydrothermal coeffi cient (HTC) from 0.57 in 2009 to 1.1 in 2014. Assessing the incidence of the fi ve most common and harmful sunfl ower diseases (dry rot, charcoal rot, gray mold, Phomopsis blight, downy mildew) by cluster analysis for the ten-year study period in relation to the weather conditions of a year, we found that both dry and charcoal rots were co-associated with aridity, while downy mildew and gray mold were frequently promoted by waterlogging during a certain period of sunfl ower development. Unlike the other diseases, Phomopsis blight, being an annual disease, appears to have no clear dependence on any specifi c conditions. Conclusions. Based on the phytosanitary monitoring results of crops in the Eastern Forest-Steppe of Ukraine, the sunfl ower phytopathogen complex composition was determined. The prevalence degrees for Phomopsis blight, gray mold, dry rot, charcoal rot, and downy mildew as well as the development intensities of Phomopsis and gray mold were established. The co-incidence of the fi ve most harmful sunfl ower diseases in the Eastern Forest-Steppe of Ukraine (dry rot, charcoal rot, gray mold, Phomopsis blight, downy mildew) was evaluated during the ten-year study period, depending on the weather conditions of a year.

Macrophomina is a genus belonging to Botryosphaeriaceae that comprises well-known necrotrophic pathogens related to hundreds of plant hosts around the world. Historically, M. phaseolina is the causal agent of charcoal rot in several crops, mainly in tropical and subtropical areas around the world. However, after a recent genetic diversity study using morphological and molecular approaches, which resulted in the epitypification of M. phaseolina, and the description of a new Macrophomina species associated with charcoal rot disease, the hypothesis that other cryptic species could be present under the name M. phaseolina was raised. Previous studies in Brazil revealed a high genetic diversity and different levels of aggressiveness of M. phaseolina isolates associated with charcoal rot in oilseed crops. Thus, the aim of the present study was, through phylogenetic and morphological studies, to determine if isolates of Macrophomina obtained from different oilseed crops represent a single species or distinct taxa. Based on the results obtained, it was possible to identify three different Macrophomina species: M. phaseolina, M. pseudophaseolina and a new phylogenetic species, M. euphorbiicola. This is first report of M. pseudophaseolina in Brazil causing charcoal rot on Arachis hypogaea, Gossypium hirsutum and Ricinus communis and associated with seed decay of Jatropha curcas. In addition, a novel species described in the present study, M. euphorbiicola, is reported as the etiological agent of the charcoal rot on R. communis and Jatropha gossypifolia.

&nbsp; Charcoal rots (Macrophomina phaseolina&nbsp;(Tassi) Goidanich) of soybean (Glycine max&nbsp;(L.) Merr.) is a disease of economic significance throughout the world. Pathogenicity of 14 isolates of&nbsp;M. phaseolina&nbsp;was tested on soybean cv. Giza 21 under greenhouse conditions. The obtained data indicated that all the obtained isolates were able to attack soybean plants and caused charcoal rot on the basal stem with various degrees of diseases severity.&nbsp;M. phaseolina&nbsp;isolate S13 caused the highest charcoal rot severity (60%) followed by isolates S11 and S8 (57.9 and 56.3%, respectively). The effect of two inducer chemicals, that is, riboflavin (B2) and&nbsp;thiamine (B1) on the induction of systemic resistance in soybean against charcoal rot disease as well as biochemical changes associated with these treatments in soybean plants was investigated. Under greenhouse condition, the dose effect of 0.1 to 15 mM riboflavin and thiamine showed that 2.5 mM of riboflavin and 5 mM of thiamine was sufficient for maximum induction of resistance; higher concentration did not increase the effect. On the other hand, plants treated with riboflavin and thiamine and inoculated with pathogen grew higher than plants treated with sterilized distilled water (SDW) and inoculated with pathogen and increased fresh and dry weight of soybean plants. 10 mM concentration of riboflavin and thiamin recorded the highest dry and fresh weight compared with the control. In time course observation, it was observed that riboflavin and thiamine treated soybean plants induced resistance one day after treatment and reached its maximum level from 5 to 7 days in the case of riboflavin and 6 to 8 days in the case of thiamine and then decreased. Under field conditions, the percentage of damping-off, root rot and/or charcoal rot severity were significantly reduced due to soaking of the seeds in any of riboflavin and thiamine before sowing compared with the control treatment (seed treated with water) in both seasons (2008 to 2009 and 2009 to 2010). Also, these treatments significantly increased nodule numbers per plant, fresh and dry weight of nodules per plant compared with the control in both seasons. Generally, thiamine gave the best results in most cases under greenhouse and field conditions. In physiological studies, activity of defense-related enzymes, including peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), pathogenesis related (PR) protein (chitinase), were increased in the inoculated and non-inoculated plants treated with the thiamine and riboflavin respectively, compared with the control during the experimental period. In general, activity of these enzymes began to accumulate after two days of treatment and reached maximum levels at 8, 6, 8 and 8 days for PO, PPO, PAL and chitinase, respectively then the activities of these enzymes decreased progressively. On the other hand, total phenols and lignin increased in soybean plants inoculated with&nbsp;M. phaseolina&nbsp;and treated with thiamine and riboflavin. The highest accumulation of phenols was recorded 6 days after treatment, while lignin recorded the highest level at the 10th day from application. These results suggested that these chemicals mayplay an important role in controlling the soybean charcoal rot disease, through induction of systemic resistance in soybean plants. &nbsp; Key words:&nbsp;Soybean, charcoal rot, thiamine, riboflavin, induced resistance.

Unveiling the biocontrol potential of Pseudomonas syringae through seed biopriming against charcoal rot disease in maize

Sorghum is an important crop of semi arid regions where it suffers from several biotic stresses. Among biotic stresses, charcoal rot/stalk rot is a major constraint for rabi (post rainy) sorghum production. Identification of stable resistant sources and incorporation of the genes or quantitative trait loci (QTL1) governing resistance are the prerequisite to make progress in breeding for charcoal rot resistance. A set of 242 sorghum minicore collection were phenotyped in sick plot of charcoal rot disease. A total of 31 polymorphic EST-SSR markers were developed and mapped through association analysis. The population structure analysis indicated the partitioning of the genetic population structure into four clusters. In the current study six new markers were identified for charcoal rot disease resistance (Xiabt 210, Xiabt 527, Xiabt 301, Xiabt 37, Xiabt 77, Xiabt 81) and was validated previously identified flanking markers for charcoal rot disease QTLs (locus Xiabt 275) at RARS Vijayapura location. Six marker trait associations were stable at two locations and these significant associations are useful and suitable for marker assisted selection in charcoal rot disease resistance breeding programs.

Since sesame accessions differ significantly in many morphological and phenotypical traits, some of these traits could be suitable for direct selection for resistance to Fusarium wilt and charcoal rot diseases. Forty-eight sesame accessions that originated from different countries were screened for their reaction to infection by &lt;I&gt;Fusarium oxysporum&lt;/I &gt; f.sp. &lt;I&gt;sesami&lt;/I&gt; (FOS) and &lt;I&gt;Macrophomina phaseolina&lt;/I&gt; (MPH), the Fusarium wilt and charcoal rot pathogens, respectively, in 2005 and 2006. The level of infection and seed yield were measured. Number of branches and days to maturity as morphological traits and seed color as phenotypical trait, which represent some of the diversity among the accessions, were tested for possible correlation with infection percentage. We found that 57, 67 and 67% in 2005, and 77, 77 and 62% in 2006 of the accessions resistant to FOS, and 68, 77 and 64% in 2005, and 80, 76 and 60% in 2006 of the accessions resistant to MPH had a medium branch number, medium maturity and creamy seed colour. According to the analysis of regression, branch number and seed colour were significantly correlated with infection percentages by FOS and/or MPH. Therefore, these traits may be used for direct selection of sesame accessions that are resistant to Fusarium wilt and charcoal rot disease. However, no significant correlations were found between days to maturity and infection percentage by both fungi. Linear regression between infection percentage and three groups of branch number and seed colour indicated that the accessions with medium branch number and creamy or white seed colour were the only covariate which significantly correlated with the infection percentage by FOS and/or MPH.