Netnapis Khewkhom - Academia.edu (original) (raw)

Papers by Netnapis Khewkhom

European journal of plant pathology, Jan 26, 2024

E3S web of conferences, 2021

Fusarium wilt disease attacks the tomato plants, and Solanaceae plants with losses can reach 90 %... more Fusarium wilt disease attacks the tomato plants, and Solanaceae plants with losses can reach 90 %. Thus, this disease was tough to control. The morphology and pathogenicity variation caused failure disease control. Both variations could be affected by the altitude of the planting site. Therefore, it also required special handling of management as well. The specific objectives of this study to investigate the Fusarium isolate from different altitude response of physical properties (acid-base pH, low-high temperature, and fungicides of other active ingredients) and growth rate of Fusarium. All Fusarium sp. were isolated from the leaves, soil, roots, and stem of infected tomato plants. Before a series of tests were carried out, all of the isolates were tested for pathogenicity, then tested for the influence of abiotic factors. This study obtained four isolates from high altitude, four isolates from medium altitude, and five lowland isolates. In morphological observations, there were striking differences in colony color and growth rate among isolates on several media and pathogenicity tests. Each isolate had different pathogenicity, although from the same location but other parts of the plant. Knowing the characteristic morphology and Fusarium sp. response of the three areas can be used as references in controlling.

Chiang Mai Journal of Science

Red rot disease caused by Colletotrichum falcatum is a major production threat to several sugarca... more Red rot disease caused by Colletotrichum falcatum is a major production threat to several sugarcane varieties in Thailand. Biological control is an ecologically friendly alternative to manage the disease using microbial antagonism and associated metabolic products. In this study, four Aspergillus non-toxigenic strains (A37, A374, A400, and A561) were characterized using a genetic approach and evaluated for their antagonistic potential to suppress the growth of C. falcatum. The strain A561 had the maximum number of gene deletions, with 12 afl atoxin-producing genes being lost. In addition, the non-toxigenic characteristic of A561 was confi rmed using afl atoxin B1 (AFB1) enzyme-linked immunosorbent assay. A561 reduced the concentration of AFB1 by 98.57% (1.63 μg/kg) relative to the toxigenic control. The antagonistic activity of A561 was evaluated against C. falcatum using the competition plate method on potato dextrose agar (PDA) in vitro. The results revealed that A561 inhibited th...

Journal of Fungi

The plant pathogen Fusarium graminearum is a proficient producer of mycotoxins and other in part ... more The plant pathogen Fusarium graminearum is a proficient producer of mycotoxins and other in part still unknown secondary metabolites, some of which might act as virulence factors on wheat. The PKS15 gene is expressed only in planta, so far hampering the identification of an associated metabolite. Here we combined the activation of silent gene clusters by chromatin manipulation (kmt6) with blocking the metabolic flow into the competing biosynthesis of the two major mycotoxins deoxynivalenol and zearalenone. Using an untargeted metabolomics approach, two closely related metabolites were found in triple mutants (kmt6 tri5 pks4,13) deficient in production of the major mycotoxins deoxynivalenol and zearalenone, but not in strains with an additional deletion in PKS15 (kmt6 tri5 pks4,13 pks15). Characterization of the metabolites, by LC-HRMS/MS in combination with a stable isotope-assisted tracer approach, revealed that they are likely hybrid polyketides comprising a polyketide part consis...

Plant disease specimen samples caused by fungal pathogens were collected and brought to the labor... more Plant disease specimen samples caused by fungal pathogens were collected and brought to the laboratory at the Department of Plant Pathology, Faculty of Agriculture, Kasetsart University,Bangkhen campus,Thailand. The specimen samples were recorded for disease symptoms with a flat bed scanner. A closed-up symptom of the disease tissues was then, taken for photomicrographs under a stereo zoomed microscope attached with microscope adapter to a digital camera. The diseased specimens with fungal fruiting bodies were dissected and prepared in either water or lactophenol mounting medium. Photomicrographs of fruiting bodies, spores and important characteristics of each fungal pathogen were then taken from the prepared glass slides with digital camera attached to a research microscope. Data obtained from all of the steps of record were imported into Microsoft word with A4 page size and make a compilation steps of disease symptoms and main morphological characteristics of fungal pathogen as gu...

The lipophilic extract of 16 plant extracts of the Rutaceae family was selected for investigation... more The lipophilic extract of 16 plant extracts of the Rutaceae family was selected for investigation of antifungal properties. Antifungal active compounds bioautography bioassays against Cladosporium herbarum have been detected. Comparative studies of Toddalia sp. (leaves), Limonia acidissima (leaves), Vepris bilocularis (leaves), Coleonema pulchellum (roots), Triphasia trifoliata (leaves), Pleiospermum alatum (leaves and stem), Acronychia pedunculata (leaves), and Atalantia sp. (leaves) extract showed clear inhibition zones on TLC plates against C. herbarum. In microdilution bioassay, the leaf extracts of Fortunella hindsii exhibited the strongest fungicidal activity with a MIC value at 312.5 μg/mL and showed an inhibition of spore germination at EC50 of 114 μg/mL for Botrytis cinerea. L. acidissima leaf extracts displayed a MIC of 1250 μg/mL and showed an inhibition of spore germination with EC50 0 values at 589 μg/mL for B. cinerea. The leaf extracts of two different collections of ...

Jordan Journal of Biological Sciences, 2021

Tomato (Solanum lycopersicum L.) is one of the most economically important vegetable crops in Ind... more Tomato (Solanum lycopersicum L.) is one of the most economically important vegetable crops in Indonesia. Tomato diseases caused by fungi are transmitted by seed or transplants. Fusarium wilt disease is a cosmopolitan species caused by Fusarium oxysporum Schlecht. Emend. Snyder & Hansen. Among this special attention of disease caused by F. oxysporum has been given to stem and root rotting. Six selected Fusarium samples from previous research were prepared using a single spore method and cultured in the PDB medium, The Research carried out in the Agrotechnology Laboratory of the University of Muhammadiyah Malang. DNA extraction and PCR used ITS 1 and ITS 4, electrophoresis, and data analysis was achieved at the Genetic and

Lipophilic crude extracts of Aglaia argentea, A. oligophylla, A. elaeagnoidea, A. spectabilis, an... more Lipophilic crude extracts of Aglaia argentea, A. oligophylla, A. elaeagnoidea, A. spectabilis, and A. cucullata (Meliaceae) were tested on their effectiveness on growth inhibition of posthavest pathogens. Bioassayguided fractionation led to the isolation of three active flavaglines. These were elucidated and identified by using spectroscopic methods (NMR, UV and IR) as aglafoline and didesmethylrocaglamide from A. argentea, and rocaglaol from A. oligophylla. A 96-well microbioassay revealed that rocaglaol produced high growth inhibition of Botrytis cinerea, Colletotrichum gloeosporioides, and Pestalotiopsis sp. With EC50 values at 0.05 μg/mL against Pestalotiopsis sp., 1.2 μg/mL against Botrytis cinerea, and 52 μg/mL against Colletrotrichum gloeosporioides. The activity of rocaglaol is comparable with or sometimes even higher as commercial fungicides.

Food Control, 2021

Abstract Arabica coffee is one of the most popular varieties globally; however, during postharves... more Abstract Arabica coffee is one of the most popular varieties globally; however, during postharvest and storage, it can be contaminated by fungi which produce mycotoxins such as ochratoxin A (OTA). The goal of this study was to determine fungal contamination and OTA levels of arabica coffee produced from Chiang Rai and Chiang Mai provinces in Northern Thailand. Aspergillus and Penicillium were mainly isolated and evaluated from coffee samples in the postharvest process. Coffee cherries, parchment coffee, and green coffee beans were commonly found contaminated with fungi. Coffee beans were contaminated with Penicillium, Aspergillus section Flavi, Aspergillus section Nigri, and Aspergillus section Circumdati at 1.2–10%. Fungal contamination in parchment coffee was studied using three drying methods. The results showed that coffee dried in a greenhouse had higher fungal contamination than samples dried on concrete ground or on a bamboo table. Whether basic storage packaging of green coffee beans affects fungal contamination was also investigated. Green coffee beans in three packaging types showed similar levels of Penicillium, while of the three packaging types, coffee in a polypropylene woven bag showed significantly less Aspergillus than those in a ramie sack or a plastic mesh bag. Fourteen strains of Aspergillus section Circumdati were isolated from coffee samples and 5 isolates showed green-blue fluorescence under ultraviolet light suggesting a potential of OTA production. The morphology of Aspergillus section Circumdati isolates were studied and five isolates with similar morphological characters were further identified to the species level based on ITS and the β-tubulin gene regions. Sequencing and phylogenetic analysis suggested that four isolates were grouped with A. westerdijkiae and one isolate with A. melleus. Analysis of OTA in parchment coffee, green coffee beans, and roasted coffee was performed using HPLC. The results showed that OTA was detected in only one sample of roasted coffee at 0.39 μg kg-1.

E3S Web of Conferences, 2021

Fruit rot disease is very damaging to cacao pods, which is caused by Phytoptora palmivora. The at... more Fruit rot disease is very damaging to cacao pods, which is caused by Phytoptora palmivora. The attack rate of P. palmivora varies. In Java, losses due to this disease reduce yields by 90 %. P. palmivora is a soil–borne pathogen. It is currently included in the Kingdom Chromista. Control with fungicides is not successful at this time, the alternatives is biologis control with Trichoderma sp. This research used a Completely Randomized Design (CRD) which was arranged in factorial with two factors. The first factor was Trichoderma sp. the second factor was P. palmivora. All treatment combinations were repeated three times. Trichoderma sp. antagonist test to P. palmivora was analyzed using Analysis of Variance (ANOVA) and then further tested using a 5 % BNJ. Trichoderma sp. origin from Jember and Trenggalek districts, East Java, Indonesia were able to act as antagonists against P. palmivora with the highest inhibitory of 78 %. In comparison, the lowest inhibitory was 70 % of isolates fro...

Asia Pacific Symposium on Postharvest Research, Education and Extension, 2012

I International Conference on Postharvest Pest and Disease Management in Exporting Horticultural Crops - PPDM2012, 2013

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2013

Asian Journal of Food and Agro-Industry, 2009

The objective of this study was to investigate the efficacy of three crude extracts on the infect... more The objective of this study was to investigate the efficacy of three crude extracts on the infection of two important postharvest pathogens of mango fruit. The in vitro the activity of eugenol oil against Colletotrichum gloeosporioides and Botryodiplodia theobromae and also the possibility of integrating crude extracts to reduce postharvest decay of mango was investigated. Lipophilic extracts of three spices; Cinnamomum zeylanicum, Boesenbergia pandurata and Syzygium aromaticum were selected for investigation of their antifungal properties. Antifungal compounds against Cladosporium cladosporioides were detected using silica TLC plates in bioautography. Comparative studies of all the extracts showed clear inhibition zones on TLC plates against C. cladosporioides. In a micro dilution bioassay, the trunk bark extract of C. zeylanicum showed the highest fungicidal activity with a minimum inhibitory concentrations (MIC) value at 1.2 μg/mL against C. gloeosporioides and B. theobromae at 2...

Postharvest Biology and Technology, 2013

This article appeared in a journal published by Elsevier. The attached copy is furnished to the a... more This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: