Data on the ultrastructural characteristics of Paenibacillus polymyxa isolates and biocontrol efficacy of P. polymyxa ShX301.

We present the data corresponding to the ultrastructural characteristics of Paenibacillus polymyxa isolates and control efficacy of P. polymyxa ShX301 for controlling Verticillium wilt of cotton, isolated in experimental fields at the Sanyuan Agricultural Experiment Station of North-West Agriculture and Forestry University, Sanyuan county, Shaanxi province, China. Ultrastructural characteristics of P. polymyxa isolates made using technique of transmission electron microscopy. A strain ShX301 has a broad-spectrum antifungal activity against V. dahliae and other plant pathogens and has been used for in vitro experiments for controlling this disease in greenhouse, "Biocontrol potential of Paenibacillus polymyxa against Verticillium dahliae infecting cotton plants" [1].

A new species of Scopulariopsis and its synergistic effect on pathogenicity of Verticillium dahliae on cotton plants.

A new species, Scopulariopsis gossypii, was found to be present in the vascular bundles of cotton plants (Gossypium hirsutum) infected by Verticillium dahliae which is an economically important pathogen in Hangzhou, China. The fungus was only present in the diseased plants, but it never became isolated from the healthy plants. Scanning electron microscopy showed that the fungus was present in parenchyma cells enclosing vessels in dark brown vascular tissues of stems, and produced asexual conidia within the tissues. Phylogenetic analysis of combined nuclear ribosomal D1/D2 region of the 28S rDNA as well as translation elongation factor 1-alpha (TEF1) and beta-tubulin (TUB) gene showed that S. gossypii represents an undescribed species of Scopulariopsis, Microascaceae. In this study, characteristics of sexual and asexual stages of the fungus were described, illustrated and compared with similar taxa. In addition, the molecular and morphological analyses indicated that S. gossypii was a distinct species of Scopulariopsis. The pathogenicity tests proved by inoculation of wounded roots confirmed that S. gossypii was an opportunistic pathogen causing leaf interveinal chlorosis and vascular browning of cotton plants. However S. gossypii did not infect host with undamaged roots. Moreover, coinoculation with S. gossypii and V. dahliae significantly increased disease severity.

Inhibitory effect and enzymatic analysis of E-cinnamaldehyde against sclerotinia carrot rot.

This study was conducted to determine the inhibitory effect of E-cinnamaldehyde (EC) against causal agent of storage carrot rot, Sclerotinia sclerotiorum, under in vivo and in vitro conditions. Based on the results, EC was able to completely inhibit mycelial growth of three isolates (P>0.05) in both volatile and contact phases after 6days at the concentrations 200µl and 1µl/ml, respectively. In addition, EC at concentrations 1 and 10µl/ml completely inhibited carpogenic germination of three isolates. The results of in vivo trials showed that EC at the concentration of 10µl/ml was able to control the disease caused by isolates 1 and 3. However the disease caused by isolate 2 was inhibited with the concentration of 20µl/ml. In enzyme analyses, the activity of polyphenoloxidase and peroxidase did not change in the inoculated carrots after application of EC. Furthermore, the level of phenylalanine ammonia lyase decreased. These results indicated that EC does not have any potential to be considered as resistance inducers against sclerotinia carrot rot.

Gene Expression of Type VI Secretion System Associated with Environmental Survival in Acidovorax avenae subsp. avenae by Principle Component Analysis.

Valine glycine repeat G (VgrG) proteins are regarded as one of two effectors of Type VI secretion system (T6SS) which is a complex multi-component secretion system. In this study, potential biological roles of T6SS structural and VgrG genes in a rice bacterial pathogen, Acidovorax avenae subsp. avenae (Aaa) RS-1, were evaluated under seven stress conditions using principle component analysis of gene expression. The results showed that growth of the pathogen was reduced by H2O2 and paraquat-induced oxidative stress, high salt, low temperature, and vgrG mutation, compared to the control. However, pathogen growth was unaffected by co-culture with a rice rhizobacterium Burkholderia seminalis R456. In addition, expression of 14 T6SS structural and eight vgrG genes was significantly changed under seven conditions. Among different stress conditions, high salt, and low temperature showed a higher effect on the expression of T6SS gene compared with host infection and other environmental conditions. As a first report, this study revealed an association of T6SS gene expression of the pathogen with the host infection, gene mutation, and some common environmental stresses. The results of this research can increase understanding of the biological function of T6SS in this economically-important pathogen of rice.

Ultrastructure and phylogeny of Ustilago coicis.

Ustilago coicis causes serious smut on Coix lacryma-jobi in Dayang Town, Jinyun County, Zhejiang Province of China. In this paper, ultrastructural assessments on fungus-host interactions and teliospore development are presented, and molecular phylogenetic analyses have been done to elucidate the phylogenetic placement of the taxon. Hyphal growth within infected tissues was both intracellular and intercellular and on the surface of fungus-host interaction, and the fungal cell wall and the invaginated host plasma membrane were separated by a sheath comprising two distinct layers between the fungal cell wall and the invaginated host plasma membrane. Ornamentation development of teliospore walls was unique as they appeared to be originated from the exosporium. In addition, internal transcribed spacer (ITS) and large subunit (LSU) sequence data showed that U. coicis is closely related to Ustilago trichophora which infects grass species of the genus Echinochloa (Poaceae).