Gordonia asplenii sp. nov., isolated from humic soil on bird’s nest fern (Asplenium nidus L.)

A novel member of the actinobacteria, designated strain A-T 0013T, was isolated from humic soil on a bird’s nest fern (Asplenium nidus L.) collected from Khao Yai National Park in Thailand. According the results of a polyphasic taxonomic study, A-T 0013T had characteristics typical of members of the genus Gordonia . The 16S rRNA gene sequence indicated that A-T 0013T shared ≤98 % sequence similarity with all members of the genus Gordonia . The most closely related species was Gordonia effusa IFM 10200T (97.92 % sequence similarity). The average nucleotide identity based on blast (ANIb) value with G. effusa IFM 10200T was 76.81 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained ribose, arabinose and galactose. The predominant menaquinone was MK-9(H2). The predominant fatty acids were C16 : 0, C18 : 1ω9c, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), and C18 : 0 10-methyl. Mycolic acid was present. The polar lipid profile for this strain ncluded diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol and phosphatidylinositol mannosides. The G+C content of the genomic DNA was 66.1 mol%. Differentiation of A-T 0013T from the most closely related species, Gordonia effusa IFM 10200T, was evident from digital DNA–DNA hybridization values of 21.8 %. On the basis of the results of comparative analysis of phenotypic, chemotaxonomic and genotypic data, strain A-T 0013T is concluded to represent a novel species of the genus Gordonia , for which the name Gordonia asplenii sp. nov. is proposed. The type strain is A-T 0013T (=TBRC 11910T=NBRC 114549T).

Pathogenicity of Aphelenchoides pseudogoodeyi on the ornamental plants Asplenium nidus and Lilium speciosum in Brazil

SummaryAphelenchoides pseudogoodeyi has recently been reported in association with seeds of forage grasses and rice in Brazil and senescent strawberry plants, in the United States. This nematode is likely a mycophagous species; however, so far, its pathogenicity potential to plants is unclear. This study aimed to verify the pathogenicity of A. pseudogoodeyi to two species of ornamental plants. The experiments were conducted by inoculating A. pseudogoodeyi onto Bird’s-Nest Fern (Asplenium nidus) and Oriental Lily (Lilium speciosum) leaves, using two inoculation methods (with and without injury). After 40 days of inoculation (DAI) in Bird’s-Nest Fern and 5, 10, 20 and 40 DAI in Oriental Lily, the pathogenicity and the host efficiency were evaluated by symptoms observation and by severity, final nematode population and reproductive factor (RF), respectively. Additionally, a histopathological study was performed by inoculating A. pseudogoodeyi onto Bird’s-Nest Fern for observing anatomical alterations. A. pseudogoodeyi was able to cause local necrotic lesions on both Bird’s-Nest Fern and Oriental Lily leaves. However, the presence of injury was essential to enable A. pseudogoodeyi to penetrate and cause those symptoms in both plant species. Also, the total population of A. pseudogoodeyi decreased drastically over time and RF was <1, which characterized these species as poor-host or resistant plants. A. pseudogoodeyi penetrated into the foliar tissue and induced a total destruction of the mesophyll and collapse of the cells, with the formation of large intercellular spaces. It is concluded that A. pseudogoodeyi is an opportunistic pathogen as injury was required to induce symptoms in Bird’s-Nest Fern and Oriental Lily.