The antagonistic activity of Trichoderma virens strain TvSUT10 against cassava stem rot in Thailand

In this current study, the beneficial filamentous fungi, Trichoderma virens, isolated from cassava field were investigated for antagonistic mode of action against Lasiodiplodia theobromae, the causal agent of cassava stem rot in Thailand. In vitro screening using the dual culture technique was undertaken to assess the potential of these Trichoderma isolates. Our results indicated that fifteen isolates of T. virens were collected from various areas of cassava field in Nakhon Ratchasima, Thailand. The T. virens isolate, TvSUT10, was the most effective isolate and inhibited L. theobromae mycelial growth by 84.12%, due to the antagonistic mechanism. Moreover, Trichoderma β-1,3-glucanase activity was determined, the result revealed that the highest activity was recorded in strain of T. virens TvSUT10 (25.7 U/ml). In addition, in the greenhouse experiment, the application of the TvSUT10 as a conidial suspension reduced the stem rot disease severity of cassava caused by 53%. The results indicated that the T. virens strain TvSUT10 has initial modes of action of biological control to protect cassava crop against L. theobromae infections in cassava.Key words: Trichoderma, cassava stem rot disease, growth inhibition, cassava, biocontrol

Foliar application of systemic acquired resistance (SAR) inducers for controlling grape anthracnose caused by Sphaceloma ampelinum de Bary in Thailand

Chitosan and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) are active-elicitors that induce protection in grapevine against several diseases. In this study, treatment of grapevine with chitosan and BTH provided protection to anthracnose, caused by Sphaceloma ampelinum. Chitosan and BTH treatment also increased chitinase, ß-1,3-glucanase and peroxidase activities levels in leaves over non-treated plants. Differential accumulation of these traits was more rapid and pronounced when chitosan and BTH treated plants were infected with S. ampelinum; this pattern indicating priming. The induced resistance by chitosan and BTH was also associated with increased production of salicylic acid (SA) in grapevine leaves, suggesting that SA-dependent signaling pathways are systemically triggered by these compounds. Apart from proteins with defense-related function, most of the proteins induced by chitosan and BTH were involved in defense mechanism, reflecting the strong direct positive effect that chitosan and BTH has on grapevine tolerance to anthracnose disease infection.Keywords: Anthracnose, grapevine, induce resistance, systemic acquired resistance (SAR) biochemical markers, Sphaceloma ampelinumAfrican Journal of Biotechnology Vol. 12(33), pp. 5148-515

The FTIR spectroscopy investigation of the cellular components of cassava after sensitization with plant growth promoting rhizobacteria, [i]Bacillus subtili[/i]s CaSUT007

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699To evaluate the response of cassava stakes to plant growth promoting rhizobacteria, Bacillus subtilis CaSUT007, the changes in cellular compositions and phytohormone were investigated using the fourier transform infrared (FTIR) and high-performance liquid chromatography (HPLC) approach. The objective of this study was to test the hypothesis that CaSUT007 stimulates production of plant cellular components and phytohormone involved in metabolism and growth development mechanisms. Cassava stake treated with CaSUT007 or with sterile distilled water were germinated in sterile soil, after incubation for 28 days, CaSUT007 treated cassava stakes had more lateral root, longer roots, shoot length and greater biomass than the control which enhanced more than 1.3 fold of the cassava's phytohormone as indole-3-acetic acid content of non-treated control. We also focused on plant cellular composition and cassava stake tissues from the two treatments were harvested for FTIR analysis. FTIR analyses revealed that higher accumulated of lipid in response to the strain CaSUT007. The cassava stake treated with the beneficial bacteria B. subtilis strain CaSUT007 showed the higher content of the lipid content as (shown in the spectral regions of CH stretching and CH bending mode associated with cell membrane structure lipids) when compared with those of the cassava stake treated with distilled water. Our results initially demonstrated that CaSUT007 can enhance plant growth under greenhouse conditions by direct stimulation of plant lipid and phytohormone as indole-3-acetic acid production

Application of Wood Vinegar for Fungal Disease Controls in Paddy Rice

A survey of an outbreak of fungal diseases of rice variety Phitsanulok2 (PLS91014-16-1-5-1) was conducted in Thailand during June 2014 to January 2015 using a W-random sampling pattern. The study revealed the incidence of several diseases including brown spot (Bipolaris oryzae), narrow brown leaf streak (Cercospora oryzae), and dirty panicle (Alternaria padwickii, C. oryzae, Curvularia lunata, Fusarium semitectum, and B. oryzae). This study evaluated the efficacy of wood vinegar for control of these fungal diseases. A compleel randomized design was used, using the above variety in 3 replications. In the laboratory we found wood vinegar to be effective in inhibiting growth of representative pathogens such as C. lunata, B. oryzae, F. semitectum, and A. padwickii, the causal agent of dirty panicle disease. The field results confirmed the efficacy of wood vinegar under greenhouse conditions, with significantly reduced disease incidence of brown spot and dirty panicle, and significantly enhanced germination, seedling vigor, shoot height, root length, and fresh weight, when compared with the untreated control. However, seed treatment and 6 foliar sprays of wood vinegar under field conditions at Ang Thong showed no significant differences from the conventional treatment in suppression of brown spot, narrow brown leaf streak, and dirty panicle. The result demonstrates a promising alternative approach to control of key rice diseases

Biochemical adaptation of phytopathogenic fungi, Sclerotium rolfsii, in response to temperature stress

Temperature stress plays a critical influence on microbial survival and ecology. It has been reported to be associated with direct effects on microbial metabolisms, but there are very few studies in literature which have reported it in phytopathogenic fungi. In this study, we investigated the impact of two different temperature conditions, 28 and 32°C on the changes of Sclerotium rolfsii cellular components using Fourier transform infrared (FT-IR) spectroscopy and enzyme activities measurement. Our results demonstrate that growth, sclerotia germination and biomass of S. rolfsii were obviously increased at 32°C. The changes in defense enzymes activity as peroxidase (POX) generally decrease and changed at 32°C. Moreover, the culture of S. rolfsii grown at 32°C shows the higher content of the lipid content as shown in the spectral regions of CH stretching and bending bands, when compared with those of this fungi culture under temperature at 28°C, indicating that these indicators played a role in biochemical adaptation in S. rolfsii, probably due to enhanced activity of the fungal metabolism pathway and cell wall/membrane protection to temperature stress. Our findings illustrate that temperature stress caused increase biomass and lipid composition; whereas decrease in POX activities, which is a key enzyme helps S. rolfsii cope with survival at higher temperature. Key words: Sclerotium rolfsii, enzyme activities, stress response, cellular composition, FT-IR spectroscopy

The plant growth promoting bacterium Bacillus sp. CaSUT007 produces phytohormone and extracellular proteins for enhanced growth of cassava

International audienceBacillus sp. strain CaSUT007, a plant growth promoting rhizobacterium isolated from cassava, was investigated for the secretion of compounds that might be involved in plant growth promotion. Extracts containing phytohormone and extracellular proteins were made from the cell-free fluid of CaSUT007 broth cultures. These extracts, along with a whole culture of CaSUT007 and the raw fluid and cellular fractions from a CaSUT007 culture, were applied separately to cassava stakes. The stakes were planted into pots of soil maintained in a greenhouse condition. Under this condition, all of the extracts including phytohormones and extracellular proteins increased root and shoot lengths and cassava biomass as compared to negative control. Our results indicate that the culture extracts, when applied to cassava stakes, increased root and shoot lengths by more than 30%, and increased fresh and dry weights by more than 25% compared to the distilled water control. Thus, photohormone and extracellular proteins secreted by CaSUT007 can influence plant growth and development. Analysis of the photohormone and extracellular proteins extracts revealed indole-3-acetic acid and peptides to be the primary compounds

The Effects of Soybean Meal on Growth, Bioactive Compounds, and Antioxidant Activity of <i>Hericium erinaceus</i>

Hericium erinaceus (Bull.:Fr) Pers. is a medicinal mushroom that has various health benefits and is a rich source of bioactive compounds and antioxidant activity. In recent years, H. erinaceus has been considered for its many medicinal properties and is widely consumed in Asian countries. Remarkably, the effect of mushroom cultivation using substrates composed of soybean meal by-products on growth, as well as the enhancement of bioactive compounds and antioxidant activity, was evaluated. Our results confirmed that using soybean meal-produced H. erinaceus displayed a higher mycelial growth and biological efficiency than the control treatment. Bioactive compounds with triterpenoid content and total phenolic content of H. erinaceus grown on soybean meal contained the highest values at 56.78–69.15 mg Urs/g DW and 15.52–16.07 mg GAE/g DW, respectively, while H. erinaceus grown on the control treatment had the lowest value at 32.15 mg Urs/g DW and 7.75 mg GAE/g DW, respectively. In addition, H. erinaceus cultivated on soybean meal had higher DPPH activities than those grown on the control treatment, with IC50 values of 0.67–0.89 and 1.08 mg/mL, respectively. Therefore, this study provided baseline information on the potential role of soybean meal by-product substrates in H. erinaceus growth and their effect on bioactive compounds and antioxidant activity

Efficacy of Agricultural and Food Wastes as the Growing Media for Sunflower and Water Spinach Microgreens Production

The growing media is one of the significant elements affecting microgreens’ yield and quality. This experiment investigated the possibility of waste utilization instead of employing peat moss to produce sunflower and water-spinach microgreens. The treatments consisted of peat moss (Control), coconut coir dust (CD), leaf compost (LC), food waste compost (FC), CD:LC = 1:1 v/v, CD:FC = 1:1 v/v, LC:FC = 1:1 v/v, and CD:LC:FC = 1:1:1 v/v. The results proved that the highest yield of sunflower microgreens was observed when cultivated in 1:1 v/v of CD:LC media (10,114.81 g m−2), whereas the highest yield of water spinach microgreens was recorded under the treatments of CD, Control, 1:1 v/v of CD:LC, and 1:1:1 v/v of CD:LC:FC media (10,966.67–9800.00 g m−2). The biochemical composition of the microgreens varied within the types. Our findings demonstrated that a tendency of an increase in chlorophyll and carotenoid contents depended on the growth of both microgreens under different growing media. All growing media did not cause excess nitrate residue or pathogenic contamination in both microgreens, namely Clostridium perfringens, Salmonella spp., and Staphylococcus aureus. In contrast, almost all the growing media resulted in a higher population of Bacillus cereus contamination in both microgreens than the standard set limit, except for sunflower microgreens grown in the control and CD growing media. These findings could suggest that the 1:1 v/v of CD:LC and CD media were the most effective growing media for sunflower and water spinach microgreens, respectively, but further cleaning before consumption is recommended to avoid or reduce the foodborne incidences caused by B. cereus in microgreens

Identification of an Operon, Pil-Chp, That Controls Twitching Motility and Virulence in Xylella fastidiosa

Xylella fastidiosa is an important phytopathogenic bacterium that causes many serious plant diseases, including Pierce`s disease of grapevines. Disease manifestation by X. fastidiosa is associated with the expression of several factors, including the type IV pili that are required for twitching motility. We provide evidence that an operon, named Pil-Chp, with genes homologous to those found in chemotaxis systems, regulates twitching motility. Transposon insertion into the pilL gene of the operon resulted in loss of twitching motility (pilL is homologous to cheA genes encoding kinases). The X. fastidiosa mutant maintained the type IV pili, indicating that the disrupted pilL or downstream operon genes are involved in pili function, and not biogenesis. The mutated X. fastidiosa produced less biofilm than wild-type cells, indicating that the operon contributes to biofilm formation. Finally, in planta the mutant produced delayed and less severe disease, indicating that the Pil-Chp operon contributes to the virulence of X. fastidiosa, presumably through its role in twitching motility.United States Department of Agriculture Cooperative State Research, EducationUnited States Department of Agriculture Cooperative State Research, EducationUniversity of CaliforniaUniversity of CaliforniaNanobiotechnology CenterNanobiotechnology CenterNational Science Foundation (NSF)National Science Foundation (NSF)[ECS-9876771

Characterization of the <i>Xylella fastidiosa</i> PD1671 Gene Encoding Degenerate c-di-GMP GGDEF/EAL Domains, and Its Role in the Development of Pierce’s Disease

<div><p><i>Xylella fastidiosa</i> is an important phytopathogenic bacterium that causes many serious plant diseases including Pierce’s disease of grapevines. <i>X</i>. <i>fastidiosa</i> is thought to induce disease by colonizing and clogging xylem vessels through the formation of cell aggregates and bacterial biofilms. Here we examine the role in <i>X</i>. <i>fastidiosa</i> virulence of an uncharacterized gene, PD1671, annotated as a two-component response regulator with potential GGDEF and EAL domains. GGDEF domains are found in c-di-GMP diguanylate cyclases while EAL domains are found in phosphodiesterases, and these domains are for c-di-GMP production and turnover, respectively. Functional analysis of the PD1671 gene revealed that it affected multiple <i>X</i>. <i>fastidiosa</i> virulence-related phenotypes. A Tn5 PD1671 mutant had a hypervirulent phenotype in grapevines presumably due to enhanced expression of <i>gum</i> genes leading to increased exopolysaccharide levels that resulted in elevated biofilm formation. Interestingly, the PD1671 mutant also had decreased motility <i>in vitro</i> but did not show a reduced distribution in grapevines following inoculation. Given these responses, the putative PD1671 protein may be a negative regulator of <i>X</i>. <i>fastidiosa</i> virulence.</p></div