A Novel Yeast Genus and Two Novel Species Isolated from Pineapple Leaves in Thailand: Savitreella phatthalungensis gen. nov., sp. nov. and Goffeauzyma siamensis sp. nov.

Four yeast strains, representing one genus and two novel anamorphic yeast species, were isolated from pineapple leaves collected in Thailand. Analysis of the sequences of the D1/D2 domains of the large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS) regions showed the two strains (DMKU-PAL186 and DMKU-PAL178) were closely related to the type strains of the Protomyces and Taphrina species, but with high nucleotide divergence. Two strains (DMKU-PAL39 and DMKU-PAL18) were found to be closely related to the type strains of Goffeauzyma iberica, but with eight nucleotide substitutions in the D1/D2 domains and 26 nucleotide substitutions in the ITS regions. In phylogenetic analyses, the strains DMKU-PAL186 and DMKU-PAL178 formed a well-separated lineage from Protomyces and Taphrina genera, confirming that they represented a distinct genus, while the strains DMKU-PAL39 and DMKU-PAL18 represented a species in the genus Goffeauzyma, which was phylogenetically distinct from other recognized species of the genus. Based on molecular analyses and phenotypic characteristics, the names Savitreella gen. nov. (Taphrinomycetes, Ascomycota) and Savitreella phatthalungensis sp. nov. are proposed to accommodate the strains DMKU-PAL186 and DMKU-PAL178, and the name Goffeauzyma siamensis sp. nov. (Tremellomycetes, Basidiomycota) is proposed to accommodate the strains DMKU-PAL39 and DMKU-PAL18

Five different sites of soil samples collected in the sago palm forest.

Soil samples were collected at Ban Hua Phru, Khuan Khanun, Phatthalung, Thailand during the summer (orange triangle, S1 to S5) and the rainy seasons (green circle, R1 to R5).</p

Supporting Fig.

Environmental variations have been observed to influence bacterial community composition, thereby impacting biological activities in the soil. Together, the information on bacterial functional groups in Phatthalung sago palm-growing soils remains limited. In this work, the core soil bacterial community in the Phatthalung sago palm-growing areas during both the summer and rainy seasons was examined using V3-V4 amplicon sequencing. Our findings demonstrated that the seasons had no significant effects on the alpha diversity, but the beta diversity of the community was influenced by seasonal variations. The bacteria in the phyla Acidobacteriota, Actinobacteriota, Chloroflexi, Methylomirabilota, Planctomycetota, and Proteobacteria were predominantly identified across the soil samples. Among these, 26 genera were classified as a core microbiome, mostly belonging to uncultured bacteria. Gene functions related to photorespiration and methanogenesis were enriched in both seasons. Genes related to aerobic chemoheterotrophy metabolisms and nitrogen fixation were more abundant in the rainy season soils, while, human pathogen pneumonia-related genes were overrepresented in the summer season. The investigation not only provides into the bacterial composition inherent to the sago palm-cultivated soil but also the gene functions during the shift in seasons.</div

Taxonomic distribution and average relative abundance of the uncultured bacterial communities.

(A) Distribution of bacterial taxonomic community and (B) and average relative abundance of uncultured bacteria (relative abundance ≥1%, n = 5) found in Phatthalung sago palm-growing soils collected during the summer (S1-S5) and rainy (R1-R5) seasons. Colour families display unique microbial phyla and distinct shades reflect microbial family. Low relative abundance refers to the summation of all taxa that failed to reach the 1% cut-off.</p

Microbial alpha and beta diversity in the soil samples collected in the sago palm forest.

Boxplot displays (A) the Shannon index, (B) Faith’s phylogenetic diversity, and (C) principal coordinates analysis (PCA) of a Bray-Curtis dissimilarity matrix.</p

Meteorological data and sago palm-growing soil properties collected in the summer and rainy seasons.

Data are mean ± S.D. of five independent replicates (n = 5). Asterisk symbol represents the significant P-value (P<0.05).</p

Functional characteristics of soil microbial communities collected in the sago palm forest.

Heatmap of metabolic and ecological functions of bacteria based on FAPROTAX prediction. Data are based on ASVs abundance (number of ASVs capable of each function) in during the summer (S1-S5) and the rainy (R1-R5) seasons.</p

Supporting tables.

Environmental variations have been observed to influence bacterial community composition, thereby impacting biological activities in the soil. Together, the information on bacterial functional groups in Phatthalung sago palm-growing soils remains limited. In this work, the core soil bacterial community in the Phatthalung sago palm-growing areas during both the summer and rainy seasons was examined using V3-V4 amplicon sequencing. Our findings demonstrated that the seasons had no significant effects on the alpha diversity, but the beta diversity of the community was influenced by seasonal variations. The bacteria in the phyla Acidobacteriota, Actinobacteriota, Chloroflexi, Methylomirabilota, Planctomycetota, and Proteobacteria were predominantly identified across the soil samples. Among these, 26 genera were classified as a core microbiome, mostly belonging to uncultured bacteria. Gene functions related to photorespiration and methanogenesis were enriched in both seasons. Genes related to aerobic chemoheterotrophy metabolisms and nitrogen fixation were more abundant in the rainy season soils, while, human pathogen pneumonia-related genes were overrepresented in the summer season. The investigation not only provides into the bacterial composition inherent to the sago palm-cultivated soil but also the gene functions during the shift in seasons.</div