A molecular phylogenetic and phylogeographic study of two forms of Calliptamus barbarus (Costa 1836) (Orthoptera: Acrididae,Calliptaminae) from two regions of Algeria

Calliptamus barbarus (Orthoptera: Acrididae) is the most polymorphic species within the genus Calliptamus. It shows a morphological polymorphism (three hind femoral spots, or only one hind femoral spot). Several studies have been made in order to distinguish the two forms: morphometry, number of ovarioles, sound production, protein and enzyme system. The aim of our work is to assess whether the two forms can be considered as different taxa and to perform a molecular phylogenetic study of two populations of C. barbarus collected from two different Algerian localities. No clear genetic differentiation was found between the samples with different morphologies. Additionally, the samples from Algeria do not form a monophyletic sister clade compared to the one formed by the sequences from GenBank from other geographical regions. Despite the morphological differences shown between the two populations, our molecular study indicates that there are no differences at a molecular level using the two mitochondrial genes COI and 16S.     

Identification and Characterization of two new Fungal Pathogens of Polygonatum odoratum (Angular Solomon's seal) in Italy

Polygonatum odoratum (Mill.) Druce (Angular Solomon's seal) is a well‐known ornamental plant and herbal drug, which is used in traditional medicine. Severe leaf spots were observed in wild Angular Solomon's seal plants in a public park in Trento, Italy. A combination of morphological and molecular characteristics, including sequence data of ITS‐rDNA, large subunit (LSU), beta tubulin (TUB) and glyceraldehyde 3‐phosphate dehydrogenase (GAPDH) led to identification of two species, namely Phoma odoratissimi and Colletotrichum dematium s. str., isolated from these leaf spots. Pathogenicity of the isolates was confirmed on wounded leaves of Po. odoratum; indeed, both species induced leaf spot symptoms on inoculated leaves within 10 days of inoculation. This is the first report of leaf spot disease caused by Ph. odoratissimi and C. dematium s. str. on Po. odoratum, which can be considered a new host for both the species examined in this study. In addition, isolation of Ph. odoratissimi represents a new record for the mycobiota of Italy.     

A Strobilurin Fungicide Relieves Bipolaris oryzae‐Induced Oxidative Stress in Rice

Although strobilurins are one of the most effective and broad spectrum classes of systemic fungicides, they may also increase plant stress tolerance by modulating the activity of antioxidant enzymes. To address this issue, the effect of azoxystrobin (Az) on the activity of antioxidant enzymes and on the concentrations of antioxidant metabolites and oxidative stress‐related compounds was studied in rice plants (cv. Metica‐1) either inoculated or not with Bipolaris oryzae, the causal agent of brown spot (BS). The Az minimally affected the enzyme activities, but consistently increased the glutathione reduced (GSH) concentrations in the noninoculated plants. The activities of superoxide dismutase, peroxidase, ascorbate peroxidase, glutathione peroxidase, glutathione reductase and glutathione‐S‐transferase were increased upon B. oryzae infection, but such increases were greatly limited in the Az‐sprayed plants. Catalase activity decreased in the inoculated plants compared to the noninoculated plants regardless of fungicide treatment. The GSH concentration increased in response to the B. oryzae infection, and the Az‐sprayed plants sustained higher levels of GSH at advanced stages of fungal infection than did the nonsprayed plants. The inoculated plants exhibited an extensive oxidative stress as evidenced by higher concentrations of hydrogen peroxide and malondialdehyde compared to the noninoculated plants, but lower and later increases were recorded in the Az‐sprayed plants than in the nonsprayed plants. Therefore, Az greatly reduces B. oryzae‐induced oxidative stress by limiting BS development rather than by activating antioxidant enzymes. The GSH, however, seems to be Az‐modulated, and this may partially explain the constrained oxidative stress observed in the Az‐sprayed plants.     

Biocontrol potential of actinomycetes against Xanthomonas axonopodis pv. punicae,a causative agent for oily spot disease of pomegranate

India is a largest producer of pomegranate with high export value. The cultivation is affected with the oily spot disease caused by Xanthomonas axonopodis pv. punicae infection. The present study aims to control the disease with newer biocontrol methods. Thirty-six isolates of X. axonopodis were isolated from different varieties of infected pomegranates fruits from Maharashtra. Forty strains of actinomycete were also isolated from natural sources and screened for their antagonistic activity against X. axonopodis isolates. Eight strains of actinomycete were screened out for their high antagonistic activity and were optimized for maximizing antibiotic production. The extracted compound from A5 strain exhibited maximum inhibitory activity against all the pathogenic isolates with a MIC in the range of 0.625 to 1.25 mg mL^?1. It was identified as Streptomyces violaceusnige by 16SrRNA gene sequencing (Accession number KP208943). The extracted compound belonged to aminoglycosides with a molecular formula C₂₂H₂₈N₃O₆ determined by thin layer chromatography, high-performance liquid chromatography, gas chromatography-mass spectroscopy, nuclear magnetic resonance spectroscopy, fourier transform infrared spectroscopy and carbon hydrogen nitrogen ratio analysis. In vivo biocontrol studies with strain A5 and its extracted compound effectively prevented the growth 36 Xanthomonas isolates inoculated on pomegranate fruits, illustrating its biocontrol potential against the oily spot disease of pomegranate.     

Biological spectrum of Trichoderma harzianum Rifai isolates to control fungal diseases of tomato (Solanum lycopersicon L.)

Three Trichoderma harzianum isolates viz., Th-Sks, Th-Ke and Th-Ar collected from respective states of India viz., Rajasthan, Kerala and Andhra Pradesh were evaluated for the management of six fungal diseases namely damping off, Fusarium wilt, Rhizoctonia wilt, early leaf spot, late blight and Septoria leaf spot in tomato. During in vitro analysis, T. harzianum isolates inhibited the pathogens’ growth. Isolate Th-Sks was the most virulent antagonist against all the test pathogens and exhibited maximum of 79.47% growth inhibition of Phytophthora infestans. Isolate Th-Sks proved most effective at suppression efficacy in the range of 95–100% and 91–100% against all diseases under glasshouse and in the field conditions, respectively. Tomato seeds treatment with isolate Th-Sks also promoted plant height (78.23 cm) and fruits yield (290 g/plant) during field trial and data were found to be not-significantly different from other isolates. Thus, it is concluded that isolate Th-Sks can be utilised as a biocontrol agent for management of fungal diseases in tomato.     

Genetic basis of resistance to zonate leaf spot disease in forage sorghum

Summary Generation mean analysis was carried out for ten crosses between two resistant and two susceptible parents to find the genetic basic of resistance to zonate leaf spot disease in forage sorghum. In all crosses except one, at least one type of non-allelic interaction was present. Both additive and dominance gene effects were significant for most crosses. Duplicate type epistasis was present for the inheritance of this disease. Resistance to this disease revealed overdominance. Appropriate breeding plans were suggested to exploit the disease resistance.     

A rapid assay for simultaneous detection of Spiroplasma eriocheiris and white spot syndrome virus in Procambarus clarkii by multiplex PCR

Aims: To establish a multiplex PCR method for simultaneous and rapid detection of Spiroplasma eriocheiris and white spot syndrome virus (WSSV) in Procambarus clarkii with recommendations for application to other crustacea. Methods and Results: Three primer sets were mixed at a ratio of 1 : 3 : 1 to amplify specific fragments of the S. eriocheiris, WSSV, P. clarkii crayfish (control organism) genomes, respectively. S. eriocheiris and WSSV were used to challenge the susceptible crustacea in the experimental groups. Total DNA of the samples was purified and detected by multiplex PCR. The PCR‐amplified products produced four groups of results as follows. One fragment of 1195 bp, amplified by the primer set ITS‐crayfish/28S‐crayfish, served as an internal control, showed no pathogen detection, thus confirming the specificity of our positive tests. Two groups represented by: (i) samples challenged by S. eriocheiris alone, or (ii) challenged by WSSV alone, yielded two fragments each; i.e. those from S. eriocheiris (271 bp) plus the internal control and those from WSSV (530 bp) plus the internal control. Finally, for the fourth group, in cases of double challenged treatments, all three amplified products were detected simultaneously. Conclusions: Simultaneous and rapid detection of two pathogens in P. clarkii is important to maintain productive and healthy crayfish in aquaculture. The direct detection of S. eriocheiris and WSSV from P. clarkii is practicable with multiplex PCR. Significance and Impact of the Study: This study shows that the two pathogens are simultaneously and rapidly detected in P. clarkii by multiplex PCR, thus increasing the efficiency of pathogen detection.     

The promise and challenges of blood spot methylomics

Epigenome-wide association studies (EWAS) are being extensively performed to identify epigenetic variants associated to complex diseases. However, EWAS may identify variants that are disease-induced rather than disease-causal. Recent studies have highlighted the use of Guthrie cards to profile the methylome at birth, permitting researchers to find epigenetic variants present in patients before they are diagnosed with clinical disease, with the implicit suggestion that these variants are more likely to be disease causal. The use of Guthrie cards for research purposes throws up a number of ethical issues. We review here the promises and pitfalls of Guthrie cards for disease research.     

Antifungal activity of aluminium‐containing salts against the development of carrot cavity spot and potato dry rot

As an alternative to the use of synthetic chemical fungicides to control plant disease, aluminium‐containing salts were evaluated for their effects on the mycelial growth of various fungal or fungus‐like pathogens and their ability to control carrot cavity spot (Pythium sulcatum) and potato dry rot (Fusarium sambucinum). Results showed that various aluminium‐containing salts provided strong inhibition of all the tested pathogens (Alternaria solani, Botrytis cinerea, F. sambucinum, P. sulcatum and Rhizopus stolonifer) with minimal inhibitory concentration of 1–10 mM. Aluminium chloride and aluminium sulphate were generally the most effective, inhibiting mycelial growth of pathogens by as much as 47% and 100%, respectively, at a salt concentration of 1 mM. Applied at 5 mM, aluminium sulphate also provided 28% and 100% inhibition of dry rot and cavity spot, respectively. Aluminium chloride (5 mM) reduced dry rot by 25% whereas aluminium lactate (5 mM) decreased cavity spot lesions by 86%. These results indicate that various aluminium‐containing salts may provide an alternative to the use of synthetic fungicides to control these pathogens.