It is well concluded that microbial composition and diversity of coral species can be affected under temperature alterations. However, the interaction of environmental accumulation of corals and temperature stress on symbiotic Symbiodiniaceae and bacterial communities are rarely studied. In this study, two groups of soft coral Sarcophyton trocheliophorum were cultured under constant (26 °C) and inconstant (22 °C to 26 °C) temperature conditions for 30 days as control treatments. After that, water was cooled rapidly to decrease to 20 °C in 24 h. The results of diversity analysis showed that symbiotic Symbiodiniaceae and bacterial communities had a significant difference between the two accumulated groups. The principal coordinate analyses confirmed that symbiotic Symbiodiniaceae and bacterial communities of both control treatments were clustered into two groups. Our results evidenced that rapid cooling stress could not change symbiotic Symbiodiniaceae and bacterial communities’ composition. On the other hand, cooling stress could alter only bacterial communities in constant group. In conclusion, our study represents a clear relationship between environmental accumulation and the impact of short-term cooling stress in which microbial composition structure can be affected by early adaptation conditions.

Entomopathogenic nematodes (EPNs) Steinernema and Heterorhabditis and their symbiotic bacteria, Xenorhabdus and Photorhabdus, have been successfully used for the control of insect pests. The objectives of this study were to survey the EPNs and symbiotic bacteria in the agricultural areas of the Phitsanulok province, Thailand, and to study the association between the soil parameters and presence of EPNs. We collected 200 soil samples from 40 soil sites in agricultural areas (field crops, horticulture crops and forest). The prevalence of EPNs was 8.0% (16/200). Fifteen of the EPN isolates were molecularly identified (based on 28S ribosomal DNA and internal transcribed spacer regions) as Steinernema siamkayai. Seven isolates of Xenorhabdus stockiae were identified using recombinase A sequencing. Phylogenetic analysis revealed that all the Steinernema and Xenorhabdus isolates were closely related to S. siamkayai (Indian strain) and X. stockiae (Thai strain), respectively. Significantly more EPNs were recovered from loam than from clay. Although the association between soil parameters (pH, temperature and moisture) and the presence of EPNs was not statistically significant, the elevation levels of the soil sites with and without EPNs were found to be different. Moreover, statistical comparisons between the agricultural areas revealed no significant differences. Therefore, we concluded that S. siamkayai is associated with X. stockiae in agricultural areas and that there is no association between the soil parameters of agricultural areas and presence of EPNs, except for soil texture and the elevation. Steinernema siamkayai may be applied as a biocontrol agent in agricultural areas.

Two nematode species living in association with chemoautotrophic prokaryotes were found in two deep-sea canyon/channel systems, the Whittard Canyon and Gollum Channels, north-east Atlantic. Parabostrichus bathyalis gen. nov. sp. nov. (Desmodorida: Desmodoridae: Stilbonematinae) relates to Eubostrichus Greeff 1869 but differs in having well-developed paired dorso-caudal apophyses of the gubernaculum, small pre- and postcloacal latero-ventral papillae with short apical setae, elongate tail with slender posterior portion, and the absence of thorn-like setae (porids) in males. Body of P. bathyalis is loosely covered with elongate cells of prokaryote ectosymbionts. Astomonema southwardorum Austen et al. 1993, originally found at a methane seep pockmark in the North Sea, constitutes a significant portion of nematode communities in certain areas of the deep-sea canyon/channel systems. Taxonomic difficulties within Astomonematinae are discussed in light of the character state of paired male gonads discovered in A. southwardorum. Canyon populations of A. southwardorum are characterized by frequent loss of part of the hind body and wound healing posterior to the vulva in females. Both species tend to occur in deeper subsurface layers of the bottom sediment. Abundance of the nematode species associated with aggregations of ectosymbiotic (Parabostrichus) and endosymbiotic (Astomonema) chemoautotrophic bacteria may indicate reduced conditions at sites in these deep-sea canyons/channels and suggests a potentially substantial ecological role for chemolitotrophic fauna there.