Kantulee peat swamp forest associated Actinomycetes and their plant growth promoting potential

Name: Aaron, Teo Wee Fei

keyword: Swamp forest.

LCSH: Kasetsart University -- Dissertations. Ph.D. (Microbiology) 2020

Classification :.LCCS: QR82.A35

LCSH: Kasetsart University. -- Department of Microbiology -- Dissertations

LCSH: Actinobacteria

LCSH: Plant growth promoting substances

Abstract: Actinomycetes had been the classical candidate for plant growth promotion as many exhibited disease suppression and plant growth regulatory activities. Actinomycetes from peat swamp forest remained under-explored. This study aimed to investigate the distribution of actinomycetes from Kantulee peat swamp forest using acidic media and to evaluate the isolated actinomycetes strains for potential application for agriculture. In this study, six acidic media formulations employed for the isolation of actinomycetes from the soil samples collected from Kantulee peat swamp forest recovered 75 actinomycetes isolates. Of these isolates, 57 isolates were classified as streptomycetes based on their colony morphology and the presence of LL-DAP in whole-cell hydrolysates, while 18 isolates were classified as non-streptomycetes. Their pH growth tolerance was assessed and results showed that 4 strict acidophiles, 7 neutrotolerant acidophiles and 64 acidotolerant neutrophiles were recovered. Twenty-three representative isolates were identified by 16S rRNA gene sequence similarity as members of the genera Amycolatopsis (two isolates), Nocardia (four isolates) and Streptomyces (17 isolates). Strains K13G38T and K81G1T showed highest 16S rRNA gene sequence similarity < 98.6 % to Amycolatopsis species with validly published name, thus were further characterized with polyphasic approach. Strains K13G38T and K81G1T were proposed as Amycolatopsis acididurans sp. nov. and Amycolatopsis acidicola sp. nov., respectively. Additionally, the in vitro tests showed that the actinomycetes isolated from Kantulee peat swamp forest displayed a varying degree of siderophore production on Chrome Azurol S agar, phosphate solubilisation on Pikovskaya agar as well as antagonistic activities against Fusarium moniliforme, Helminthosporium oryzae and Rhizocthonia solani. Subsequently, 17 acidotolerant neutrophiles actinomycetes isolates were selected for rice seed biopriming and results showed that rice seed bioprimed with isolates A. acididurans K13G38T and Nocardia sp. K12M13 demonstrated significantly longer plant length. When isolates were employed for rice seed biopriming under sterile soil environment, results showed that the rice seeds germination and seedling establishment of rice seeds inoculated with A. acididurans K13G38T showed significantly highest vigour index. Therefore, this study had demonstrated that peat swamp forest is a reservoir of undiscovered actinomycetes that could be employed for plant growth promotion.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Kannika Duangmal

Role: Thesis Advisor

Name: Nantana Srisuk

Role: Thesis CO-Advisor

Created: 2020

Modified: 2025-07-25

Issued: 2025-07-25

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2563/teo-wee-all.pdf

CallNumber: QR82.A35 .A27

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degraee

Descipline: Microbiology

Grantor: Kasetsart University

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