Natthiya Buensanteai

The FTIR spectroscopy investigation of the cellular components of cassava after sensitization with plant growth promoting rhizobacteria, Bacillus subtilis CaSUT007

To 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 cassavas 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.

Use of infrared microspectroscopy to determine leaf biochemical composition of cassava in response to Bacillus subtilis CaSUT007

The objective of this study was to investigate the growth stimulating properties of Bacillus subtilis CaSUT007 applied to cassava plants using fourier transform infrared (FTIR) microspectroscopy to monitor the production of cellular components involved in plant growth and development. Cassava stakes treated with CaSUT007 or sterile distilled water were germinated in soil. After incubation for 2 months, CaSUT007 treated plants had higher growth rate and greater biomass than the control. FTIR analysis revealed that the leaves of cassava plants treated with CaSUT007 display FTIR spectra changes in the epidermis and mesophyll tissue. These changes associated with proteins, lipids, and pectins, which are related to changes in plant cell growth and development. FTIR microspectroscopy can be used as a new tool to examine the biochemical changes within the plant tissue. This technique allows us to reveal structural chemical makeup and features of different tissue types.

Salicylic acid-induced accumulation of biochemical components associated with resistance against Xanthomonas oryzae pv. oryzae in rice

ABSTRACT Seed treatment and foliar sprays of salicylic acid (SA) provided protection in rice against bacterial leaf blight (BLB) caused by bacterial Xanthomonas oryzae pv. oryzae (Xoo). Treatment of rice with exogenous SA reduced disease severity by more than 38%. Superoxide anion production and hypersensitive response increased approximately 28% and 110% at 6 and 48 h after Xoo inoculation, respectively, for plants treated with SA. Moreover, the Xoo in treated rice plants grew more slowly, resulting in a population that was half of that observed in the control. Fourier transform infrared spectroscopy analysis revealed that the higher ratios of 1233/1517, 1467/1517, and 1735/1517 cm−1 observed in treated rice suggested alteration of monomer composition of lignin and pectin in the rice cell wall. Exogenous SA-treated rice had more amide I β-sheet structure and lipids as shown by the peaks at 1629, 2851, and 1735 cm−1. These biochemical changes of rice treated with SA and inoculated with Xoo were related to primed resistance of the rice plants to BLB disease.

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, s-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 ampelinum African Journal of Biotechnology Vol. 12(33), pp. 5148-5156

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.

Synchrotron-based FTIR microspectroscopy of chili resistance induced by Bacillus subtilis strain D604 against anthracnose disease

ABSTRACT The aim of this study was to determine the resistance mechanisms of chili induced by the Bacillus subtilis strain D604 using synchrotron FTIR microspectroscopy (SR-FTIR). In this study, the strain D604 reduced anthracnose disease severity in chili plants by approximately 31.10%. The SR-FTIR spectral changes from the epidermis and mesophyll leaf tissue revealed higher integral areas for the C=O ester from lipids, lignin, or pectin (1770–1700 cm−1) as well as polysaccharides (1200–900 cm−1) in the treated samples of D606 and distilled water and then challenge inoculation with chili anthracnose pathogen, Colletotrichum acutatum. The secondary structure of the Amide I protein failed to convert from alpha helices (centered at 1650 cm−1) to beta sheets (centered at 1600 cm−1) in the mesophyll of samples not treated with D604. This study suggested that the strain D604 induced resistance against anthracnose pathogen in chili by inducing cellular changes related to defense compounds involved in plant defense mechanism.

The gene expression of the Tvmfs transporter and defense enzyme activities from Trichoderma harzianum response to pH stress

The pH stress, one of the important environmental conditions, plays critical influence on microbial survival, colonization and ecology. It has been reported to be associated directly with its effects on microbial metabolisms, but there are few studies in literature. In current study that was investigated the impact of pH stress which is the major facilitator superfamily (MFS), a ubiquitous group of proteins involved in the transport of compounds produced by beneficial fungi, gene expression of Trichoderma harzianum. Moreover, this experiment also determined the defense enzyme activities of T. harzianum response to the pH change. The results demonstrated that fungal growth, spore germination and biomass of T. harzianum were obviously inhibited at pH 3.0 and 10.0. The pattern of Tvmfs gene expression was decreased in both pH conditions, and this suggested that this gene did functionally relate to pH stress response. Furthermore, the changes in enzyme activities including catalase and peroxidase were decreased, whereas kinase was increased with both pH stresses. Glucanase were decrease-changed as acidic and alkaline conditions. This experiment suggested that these key gene and enzymes help T. harzianum adapt for survival to pH stress, due to enhance or disrupt activity of the fungal metabolism. This is a valuable result to adjust the effective condition in growth of the beneficial fungi for biofertilizer in the near future.