# The overlooked amoebae of an agroecosystem of black soil land in China: five new species of dictyostelids

## TL;DR

This study discovers five new species of dictyostelid amoebae in China's black soil region, highlighting their diversity in agroecosystems.

## Contribution

The paper reports five new dictyostelid species from understudied agroecosystems in China's black soil region.

## Key findings

- Five new dictyostelid species were identified from soil samples in Jilin Province.
- Morphological and molecular analyses confirmed the novelty of these species.
- The study provides insights into dictyostelid diversity in agroecosystems of black soil land.

## Abstract

China’s northeastern black soil region, a global black soil hotspot, is vital for supporting national food security with its fertile and agricultural-friendly soil. The dictyostelids are well-known eukaryotic microorganisms with an unusual multicellular stage in their life cycle, and they inhabit surface soils worldwide. Although numerous species have been isolated from forest ecosystems and their remarkable biological activities have been reported, species of plant-associated dictyostelids of agroecosystems remain surprisingly understudied, especially in the agroecosystems of the black soil region of Jilin Province. In this study, the diversity of this group was evaluated based on corn, cabbage, and soybean soil samples from black soil land, including mollisol and chernozem soil types in Jilin Province of China. Morphological characterization and molecular analyses of the nuclear small subunit (18S) were used for species delineation. A total of 20 strains of dictyostelids were isolated from four localities, and on the basis of morphological examination and molecular phylogenetic analyses, five species of dictyostelids are described as new to science. These are Coremiostelium viridiflava, Raperostelium macrosorus, Dictyostelium torta, Cavenderia densissima, and Polysphondylium sparsiramus. These new species are described in detail, with morphological and molecular distinctions from their closest relatives explicitly discussed. This study not only revealed the diversity of dictyostelids in agroecosystems but also provided more research data for further studies in black soil land microbe protection in China.

Despite the recognition of the presence of dictyostelids in various ecosystems, only limited information is available on their diversity and characteristics, particularly in the agroecosystems of China’s northeastern black soil region. These eukaryotic microorganisms are known for their multicellular life cycle stages and widespread occurrence in surface soils. However, the species of dictyostelid in the black soil region of Jilin Province remain largely unexplored. In this study, a total of 20 dictyostelid strains, including five newly described species, were isolated and characterized from soil samples. Morphological examination and molecular phylogenetic analysis were conducted to document these new species. This research not only revealed the diversity of dictyostelid species in this important agroecosystem but also provided valuable data for future studies on microbe protection in China’s black soil land. The discovery and detailed analysis of these new species contribute to our understanding of dictyostelid ecology, biology, and potential roles in agroecosystems.