Fodinicola acaciae sp. nov., an Endophytic Actinomycete Isolated from the Roots of Acacia mangium Willd. and Its Genome Analysis.

Huyền Thị Thanh Phạm,Wipawadee Suwannapan,Arinthip Thamchaipenet,Akira Také,Atsuko Matsumoto,Wilaiwan Koomsiri,Yuki Inahashi

doi:10.3390/microorganisms8040467

Huyền Thị Thanh Phạm, Wipawadee Suwannapan + Show 5 more

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https://doi.org/10.3390/microorganisms8040467

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Abstract

A novel endophytic actinomycete strain GKU 173T isolated from the roots of Acacia mangium Willd. showed potential plant growth promoting (PGP) activity. Phylogenetic analysis, based on 16S rRNA gene, indicated that strain GKU 173T was the most closely related to Fodinicola feengrottensis HKI 0501T—the only species in the genus Fodinicola. Morphology and chemotaxonomy of strain GKU 173T indicated that it belongs to the genus Fodinicola by having meso-diaminopimelic acid in the cell wall and xylose as the characteristic cell-wall sugars. The cellular fatty acid profile mainly comprised iso-C16:0, anteiso-C17:0, iso-C18:0, and iso-C17:0. The major menaquinones were MK-9(H4), MK-9(H6), and MK-9(H8). The main polar phospholipids contained diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). Genome analysis signified DNA G+C content of 67.81 mol%. The level of digital DNA-DNA relatedness between strain GKU 173T and the type strain was 21.30%. On the basis of polyphasic characteristics, strain GKU 173T clearly represents a novel species of the genus Fodinicola, for which the name Fodinicola acaciae sp. nov. (= TBRC 10620T = NBRC 114213T) is proposed. Furthermore, genome analysis of both strains suggested that members of the genus Fodinicola are promising sources of beneficial PGP-actinomycetes and novel secondary metabolites.

Highlights

Endophytic actinomycetes colonize the internal plant tissues and usually have a beneficial effect to the host plant by promoting growth and protecting the plant from biotic and abiotic stresses without any damage or morphological changes to the plant [1,2]
Strain GKU 173T was isolated from surface-sterilized roots of the black wattle tree (Acacia mangium Willd.) on starch-casein agar
Morphological observation on oatmeal-nitrate agar (ON) agar indicated that strain GKU 173T formed a branched substrate mycelium and abundant white aerial hyphae that fragmented into irregular rod-like elements (Figure 1)

Summary

Introduction

Endophytic actinomycetes colonize the internal plant tissues and usually have a beneficial effect to the host plant by promoting growth and protecting the plant from biotic and abiotic stresses without any damage or morphological changes to the plant [1,2]. Various PGP activity, including production of auxin to enhance plant growth, siderophores to chelate iron and other elements, 1-aminocyclopropane-1-carboxylate (ACC) deaminase to reduce plant stress ethylene, and solubilization of inorganic phosphate, were identified from several endophytic actinomycetes [3,4,5]. Reports evidencing that those endophytic actinomycetes directly improve and promote plant growth and protect plants against pathogens and abiotic stresses have been gradually increasing [5,6,7]. Recent genome mining of actinomycetes has revealed a remarkably large number of secondary metabolite biosynthetic gene clusters (BGC) [9], including substantial numbers of silent/cryptic BGCs that are potential sources for novel bioactive compounds which have not been detected under conventional method [10]

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