Two new species of dictyostelid cellular slime molds in high-elevation habitats on the Qinghai-Tibet Plateau, China

Pu Liu,Qi Wang,Yue Zou,Steven L Stephenson,Shu Li,Yu Li

doi:10.1038/s41598-018-37896-7

Abstract

Dictyostelid cellular slime molds (dictyostelids) are key components of soil microbes. The Qinghai-Tibet Plateau is characterized by unique and important forest types because of the considerable range in elevation which exists. During the period of 2012, 2013 and 2016, 12 species of dictyostelids were yielded from samples collected in this region, including two new species and three new records for China. Six other species were new records for this region. Ontogeny, morphology, ultrastructure and systematic molecular analyses (SSU & ITS) of D. minimum and D. multiforme confirm that they are Goup 4 new species. The ornamentation of the surface of dictyostelids’ spores is the first time to be observed until now. In the SSU phylogenetic tree generated in the present study, Synstelium, not assigned to order and family before, was assigned to the clade Acytosteliaceae in the Acytosteliales firstly. To our knowledge, the study reported herein is the first investigation of dictyostelid biodiversity carried out at elevations above 2000 m. Sorocarp size, sorus size, spore length, ratio of sorus and sorophore, and ratio of sorus and spore size were positively correlated with increasing elevation and no linear correlated with forest type, according to the results of linear regression analysis.

Highlights

Dictyostelids, the second largest group of slime molds, have both animal-like and fungus-like characteristics
After make an analysis of the morphological charactertistics of those dictyostelids with those forest types, we found there was no linear correlation of forest type with sorocarp size, sorus size, spore length, spore width, ratio of sorus and sorophore, and ratio of sorus and spore size
Studies of the distribution and abundance of dictyostelids associated with similar habitats at high elevations (>2000 m) are exceedingly limited

Summary

Introduction

Dictyostelids, the second largest group of slime molds, have both animal-like (protozoan) and fungus-like characteristics. The first ecological survey was carried out in the forests of southern Wisconsin in the United States, when Cavender and Raper[4] sampled six sites located along a moisture gradient Their samples were processed with the use of a quantitative method of isolation[5]. According to the traditional morphology-based classification, dictyostelids were placed in the class Dictyosteliomycetes under the phylum Protozoa This class was considered to include one order, two families and four genera[18] that are distinguished morphologically by differences in sorophore composition and branching pattern. Sheikh et al.[21] proposed a new classification based on unique 18S rRNA sequence signatures These data provided a new insight into the taxonomy of the dictyostelids, and as a result of this new classification, two families, 9 genera and 92 new combinations were recognized at the level of species and variety

Methods

Results

Conclusion