Biological treatments to control bacterial canker of greenhouse tomatoes

Experiments were conducted to determine the effects of treatments on Clavibacter michiganensis subsp. michiganensis in vitro and on young seedlingsinoculated with the pathogen under greenhouseconditions. Lysozyme was bactericidal at 10 g/l concentration in vitro. Tomato plantstreated with lysozyme at 10 g/l and 100 g/lshowed significantly higher plant heightcompared with the inoculated control plants,and plants in these treatments were as tall asthose observed in untreated uninoculatedcontrol plants. Treatments with B. subtilis (Quadra 136) and Trichoderma harzianum (RootShield®), lysozyme,vermicompostea, Rhodosporidium diobovatum(S33), B. subtilis (Quadra 137) appliedas a spray at 0.3 g/l, 0.6 g/l, 10 g/l,concentrated, 1 × 10⁹ CFU/ml, and 0.5 g/l,respectively, have the ability to prevent theincidence of bacterial canker of tomato plantscaused by C. michiganensis subsp.michiganensis under greenhouse conditions.     

基于MaxEnt模型的中国沙棘潜在适宜分布区分析

中国沙棘主要分布于我国华北、西北、西南等地森林—草原过渡地带，是我国北方地区退耕还林、生态修复等工程的重要造林树种，对维持干旱、半干旱地区的生态环境稳定具有重要意义。探讨限制中国沙棘分布的主导气候因子，模拟其潜在适宜分布区，以期为中国沙棘在林业生态工程和生态经济林建设中的合理种植和推广提供理论依据。基于中国沙棘自然分布的328个地理样点，利用最大熵(MaxEnt)模型对中国沙棘的潜在分布区的主导气候因子进行分析，并预测中国沙棘的潜在分布范围。结果表明，基于气候变量的MaxEnt模型训练集和测试集受试者工作特征曲线下面积(AUC值)分别为0.962±0.001和0.949±0.001,均大于0.9,表明MaxEnt模型对中国沙棘潜在分布区的预测具有极高的准确度，可信度好。基于环境变量贡献率和刀切法的结果表明年降雨情况、生长季的水热状况、最干季降雨和最冷月最低温等是限制中国沙棘分布的主要气候因素，其中年降雨是限制中国沙棘分布的主导气候因子。通过模拟得到现代中国沙棘潜在地理分布的总适生区面积为165.1万km~2;其中高适生区和中适生区面积共93.3万km~2,主要集中分布于河北西部、北部，...     

Production of thuringiensin from Bacillus thuringiensis using a net-draft-tube,modified airlift reactor

A net-draft-tube, modified airlift reactor and a stirred-tank reactor were used for thuringiensin production by Bacillus thuringiensis subsp. darmstadiensis growing with various concentrations of molasses. The optimum concentration of molasses for thuringiensin production in both reactors was 15 g/l. There was a 6 h delay in sporulation in the modified airlift reactor compared with that in the stirred-tank reactor. Thuringiensin yield in the modified airlift reactor (2.2 g/l) was consequently higher than that in the stirred-tank reactor (1.1 g/l).     

Screening the essential oil composition of wild Sicilian fennel

Fifty-six samples of wild fennel (Foeniculum vulgare Mill.) have been collected in different localities of Sicily and analysed for their content in seed essential oils. The GC-FID-MS analyses allowed identifying 78 compounds, representing more than 98% of the oils. Phenylpropanoids are the most highly represented components – 55 samples show estragole as the main compound ranging between 34 and 89%, while (E)-anethole is the other phenylpropanoid ranging between 0.1 and 36%, although it only reaches appreciable values in a few samples, largely being present below 1%. The oxygenated monoterpene, fenchone, a typical fennel oil component, has been found in all samples, in the 2–27% range; α-pinene (1–21%), limonene (1–17%) and γ-terpinene (<1–4%) were the monoterpene hydrocarbons found in all samples. Only one sample showed piperitenone oxide and limonene as main components, with 42 and 34%, respectively, and with the lack of any phenylpropanoid. Sesquiterpenes and others compounds class had only negligible values or were not detected in all samples. Statistical analyses allowed to single out five groups, reflecting the compositional differences of the essential oil profiles of the wild Sicilian fennel.     

The allopolyploid Arabidopsis kamchatica originated from multiple individuals of Arabidopsis lyrata and Arabidopsis halleri

Polyploidization, or genome duplication, has played a critical role in the diversification of animals, fungi and plants. Little is known about the population structure and multiple origins of polyploid species because of the difficulty in identifying multiple homeologous nuclear genes. The allotetraploid species Arabidopsis kamchatica is closely related to the model species Arabidopsis thaliana and is distributed in a broader climatic niche than its parental species. Here, we performed direct sequencing of homeologous pairs of the low-copy nuclear genes WER and CHS by designing homeolog-specific primers, and obtained also chloroplast and ribosomal internal transcribed spacer sequences. Phylogenetic analysis showed that 50 individuals covering the distribution range including North America are allopolyploids derived from Arabidopsis lyrata and Arabidopsis halleri . Three major clusters within A. kamchatica were detected using Bayesian clustering. One cluster has widespread distribution. The other two are restricted to the southern part of the distribution range including Japan, where the parent A. lyrata is not currently distributed. This suggests that the mountains in Central Honshu and surrounding areas in Japan served as refugia during glacial–interglacial cycles and retained this diversity. We also found that multiple haplotypes of nuclear and chloroplast sequences of A. kamchatica are identical to those of their parental species. This indicates that multiple diploid individuals contributed to the origin of A. kamchatica . The haplotypes of low-copy nuclear genes in Japan suggest independent polyploidization events rather than introgression. Our findings suggest that self-compatibility and gene silencing occurred independently in different origins.     

Prevalence and genomic characterization of Group A Streptococcus dysgalactiae subsp. equisimilis isolated from patients with invasive infections in Toyama prefecture,Japan

Streptococcus dysgalactiae subsp. equisimilis (SDSE) causes severe invasive streptococcal infections, especially in elderly people. Between 2013 and 2018, 88 streptococci were isolated from clinical blood culture in a hospital in Toyama prefecture, Japan. The collection included six Group A SDSE (ASD) strains, which are rarely isolated. Multilocus sequence typing categorized five of the six strains into ST128 and the remaining strain into a new type. Maximum-likelihood phylogenetic analysis revealed that the six ASD strains had highly similar genome sequences. Bayesian analysis indicated that the most recent common ancestor of the strains appeared 39 years ago. The ASD strains possessed carbohydrate synthase genes that are conserved in Streptococcus pyogenes strains, whereas one strain featured a different arrangement of the gene cluster. The carbohydrate synthase genes varied by Lancefield type (A, C, and G).     

Chemical Composition and in Vitro Antioxidant,Anti-Alzheimer,Anti-Diabetic,Anti-Tyrosinase,and Antimicrobial Properties of Essential Oils and Extracts Derived from Various Parts of the Algerian Calendula Suffruticosa Vahlsubsp. boissieri Lanza

Calendula suffruticosa Vahl subsp. boissieri Lanza is well-known for its medicinal properties in northeastern Algeria. As far as literature has been able to prove, no study has attempted to make a phytochemical or biological activity evaluation (antioxidants, enzyme inhibitors and antimicrobial potential). This work intends to evaluate, for the first time, the chemical constituents and study the previously mentioned biological activities of C. suffruticosa boissieri essential oil and different sections (flowers, leaves, roots) as well as the effect of changing the solvent (ethanol 70 %) and (methanol 70 %) on these activities. The essential oil of aerial parts of this plant was investigated using GC/MS, and 45 compounds were discovered, accounting for 98.01 % of the essential oil, including 23 monoterpenes, 6 sesquiterpenes, 12 diterpenes, 1 coumarin, 3 alkanes, methyl-cyclohexane (23.73 %), limonene (25.02 %), and o-cymene (13.20 %). Five methods were used to study the antioxidant activity (ABTS, DPPH, CUPRAC, reducing power, and β-carotene bleaching assay), where the results were impressive, especially for the essential oil. In addition, the hydroethanolic solvent (70 %) was found to be the most effective solvent for extraction in general compared to the hydromethanolic solvent (70 %). The extracts and essential oils of C. suffruticosa boissieri also showed a strong inhibiting ability against cholinesterase, tyrosinase, anti-α-amylase, α-glucosidase, and antimicrobials, a very valuable antioxidant, which is a real discovery. Based on these results, it can be said that this plant has important biological activities, so it can be used in the phytotherapy, food, or pharmaceutical sectors.     

The Invasive Woody Weed Ligustrum robustum subsp. walkeri Threatens Native Forests on La Réunion

One of the last primitive island ecosystems in the Indian Ocean has been invaded since 1969 by the Sri Lankan privet, Ligustrum robustum. L. robustum is still spreading in the forests of La Réunion Island, where only 30% of the original vegetation remains, but where 98% of the primary native vegetation of the Mascarene Islands still exists. On Mauritius, where L. robustum was introduced about 1895, it now forms dense, impenetrable thickets, and its presence has been correlated with the inability of native vegetation to re-establish. We assessed the potential impacts of L. robustum invasion on the native ecosystems of La Réunion and identified the factors of invasibility. We determined the degree of invasion in 12 plots of 156 m² and followed native flora and privet recruitment for 3 years in 12 seedling plots of 39 m². The data show that monocultural L. robustum stands now exist in human-disturbed primary forest patches (3.3 individuals/m² and 80% of total individuals) and high seedling densities (0.3–0.6/m²) occur in the least disturbed patches. L. robustum's rapid growth, high shade tolerance and seed production, bird-assisted seed dispersal and high seedling recruitment contribute to its invasiveness in intact forests. The conservation of the original ecosystems of La Réunion depends on the setting up of a long-term and immediate global control strategy. This revised version was published online in July 2006 with corrections to the Cover Date.