Now showing 1 - 3 of 3
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Morphological and Molecular Identification of Pythium spp. from Hydroponically-Grown Lettuce
    (2022-01-01)
    Talubnak, Chulalak
    ;
    Schoonbeek, Henk Jan
    ;
    ;
    Jaenaksorn, Tanimnun
    Herein, hydroponic Pythium communities in Thailand were investigated. The 38 Pythium isolates from asymptomatic and symptomatic lettuce roots were identified using morphological and molecular features. The data indicated that P. aphanidermatum and P. myriotylum were the predominant species. Regarding the rDNA-ITS study, all isolates were identified as P. aphanidermatum, P. myriotylum, P. deliense, or an unidentified Pythium species. The reconfirmation of the three unidentified Pythium isolates using the cytochrome oxidase subunit I (COI) gene in comparison to the representative isolates was achieved using P. aphanidermatum and P. myriotylum. The COI phylogenetic trees were similar to that of the ITS tree. Additionally, pathogenicity of the Pythium representative isolates to plant seeds was evaluated in a laboratory assay. The seedlings suffered serious symptoms from P. myriotylum SR31 infection, with 90-100% disease severity. The other isolates presented disease severity of less than 20% when compared with uninoculated control. This study provides a comprehensive identification of Pythium root rot in lettuce grown on hydroponics in Thailand and provides information on beneficial microorganisms and a resistance inducer in lettuce root rot.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Phytoalexin production of lettuce (Lactuca sativa L.) grown in hydroponics and its in vitro inhibitory effect on plant pathogenic fungi
    (2017-09-01)
    Talubnak, Chulalak
    ;
    ;
    Jaenaksorn, Tanimnun
    A series of experiments were conducted to investigate phytoalexin production from five varieties of lettuce in hydroponics using abiotic (2.5, 5% CuSO<inf>4</inf>; 0.5, 1% AgNO<inf>3</inf>) and biotic elicitors (non-pathogenic Pythium sp.) at different plant ages. It showed that phytoalexin was successfully induced in tested lettuce grown in hydroponics after elicitation with abiotic elicitors throughout the trial. Phytoalexin showed yellow fluorescent spot under 365 nm UV light with R<inf>f</inf> 0.45-0.48 and clear inhibition zone where Aspergillus niger failed to develop on TLC plate. For biotic elicitors, no yellow fluorescent spot on TLC plate was observed from tested lettuce varieties however inhibition zone at R<inf>f</inf> 0.9 was detected at 8-9 weeks from red oak, green oak, and red coral. Moreover, crude extract of lettuce elicited with abiotic elicitors possessed in vitro antifungal activity against C. gloeosporioides, C. lunata, F. oxysporum, and P. aphanidermatum probably due to phytoalexin (lettucenin A) in the extract.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Non-Pathogenic Pythium Induced the Resistance in Hydroponic Lettuce Against Root Rot Disease
    (2024-05-01)
    Talubnak, Chulalak
    ;
    ;
    Schoonbeek, Henk Jan
    ;
    Jaenaksorn, Tanimnun
    Hydroponics is a common soilless type of culture. It is clean and gives high-yield crop production. Lettuce is the most widely grown leafy vegetable in hydroponics. The Pythium species causes root rot, a serious disease in lettuce. In this study, we investigated an effective elicitor to promote resistance in lettuce after pathogen infection. To evaluate the plant defense gene response profile, the expression stability of five candidate genes was studied using RT-qPCR. The LsPR1 and LsLTC2 gene expression were higher in lettuce leaves treated with non-pathogenic Pythium PyASR23 than in roots compared to untreated plants. To assess the disease, the rate of relative gene expression of LsLTC2, LsPR-1b like, LsERF, LsAOS, and LsDEF was associated with Pythium root rot pathogenesis. As a result, it was revealed that alterations in these gene expressions were a defense response to Pythium infection, which increased after pre-treatment with various elicitors for 24 hours. When the chemically stimulated lettuce was infected with pathogenic PySR31, the expression of these genes increased dramatically. These results suggested that non-pathogenic PyASR23 might be employed as an elicitor in lettuce roots and contribute to disease control by activating plant defense gene expression against the Pythium pathogen.