Diversity of Xenorhabdus and Photorhabdus spp. and Their Symbiotic Entomopathogenic Nematodes from Thailand

Abstract

Xenorhabdus and Photorhabdus spp. are bacterial symbionts of entomopathogenic nematodes (EPNs). In this study, we isolated and characterized Xenorhabdus and Photorhabdus spp. from across Thailand together with their associated nematode symbionts, and characterized their phylogenetic diversity. EPNs were isolated from soil samples using a Galleria-baiting technique. Bacteria from EPNs were cultured and genotyped based on recA sequence. The nematodes were identified based on sequences of 28S rDNA and internal transcribed spacer regions. A total of 795 soil samples were collected from 159 sites in 13 provinces across Thailand. A total of 126 EPNs isolated from samples taken from 10 provinces were positive for Xenorhabdus (n = 69) or Photorhabdus spp. (n = 57). Phylogenetic analysis separated the 69 Xenorhabdus isolates into 4 groups. Groups 1, 2 and 3 consisting of 52, 13 and 1 isolates related to X. stockiae, and group 4 consisting of 3 isolates related to X. miraniensis. The EPN host for isolates related to X. stockiae was S. websteri, and for X. miraniensis was S. khoisanae. The Photorhabdus species were identified as P. luminescens (n = 56) and P. asymbiotica (n = 1). Phylogenenic analysis divided P. luminescens into five groups. Groups 1 and 2 consisted of 45 and 8 isolates defined as subspecies hainanensis and akhurstii, respectively. One isolate was related to hainanensis and akhurstii, two isolates were related to laumondii, and one isolate was the pathogenic species P. asymbiotica subsp. australis. H. indica was the major EPN host for Photorhabdus. This study reveals the genetic diversity of Xenorhabdus and Photorhabdus spp. and describes new associations between EPNs and their bacterial symbionts in Thailand.

A Photorhabdus Natural Product Inhibits Insect Juvenile Hormone Epoxide Hydrolase

“…Detailed MS and labelling experiments revealed the presence of desmethylphurealipids B ( 5 ) and C ( 6 ; Figure 1, Table S1), whose structures were confirmed by synthesis. A search for additional phurealipid-producing strains in our entomopathogenic bacteria strain collection[10] based on HPLC/MS analysis of over 250 strains revealed 1 to be widespread in P. luminescens strains (Figure 3, Figure S2) but very rare in Photorhabdus asymbiotica or Photorhabdus temperata , consistent with the fact that no plu2076 homologue could be found in the genome of P. asymbiotica . [11] However, three Xenorhabdus strains isolated in Vietnam and related to Xenorhabdus ehlersii DSM 16337 showed production of 1 (Figure S3).…”

Screening of the Antimicrobial Activity against Drug Resistant Bacteria of Photorhabdus and Xenorhabdus Associated with Entomopathogenic Nematodes from Mae Wong National Park, Thailand

“…In turn, worldwide descriptions of EPNs include approximately 26 species of Heterorhabditis and 100 species of Steinernema (Adams et al, 2006; Li et al, 2012; Thanwisai et al, 2012; Cimen et al, 2014, 2015; Malan et al, 2014; Nthenga et al, 2014; Phan et al, 2014; Vitta et al, 2015). In Thailand, at least two species of Xenorhabdus including X. stockiae and X. miraniensis have been described (Tailliez et al, 2010; Thanwisai et al, 2012) as well as two species with five subspecies of Photorhabdus ; i.e., P. luminescens subsp. akhurstii , P. luminescens subsp.…”

“…namnaonensis from across the country (Maneesakorn et al, 2011; Thanwisai et al, 2012; Glaeser et al, 2017). In addition, nine species of EPNs including S. siamkayai , S. minutum , S. websteri , S. khoisanae , S. scarabaei , H. indica , H. bacteriophora , H. baujardi , and H. gerrardi have been reported across the country (Stock, 1998; Maneesakorn et al, 2010, 2011; Thanwisai et al, 2012; Vitta et al, 2015, 2017). Distributions of EPNs and their bacterial symbionts can be influenced by climate and other ecological communities.…”

“…Distributions of EPNs and their bacterial symbionts can be influenced by climate and other ecological communities. The majority of soil locations from Thailand that EPNs have previously been isolated comprise roadside verge, fruit crops, rice fields, and the banks of rivers and ponds (Tangchitsomkid and Sontirat, 1998; Thanwisai et al, 2012; Vitta et al, 2015); however, there are no reports regarding the survey of EPNs and their symbiotic bacteria in the National Park of Thailand.…”

Entomopathogenic nematodes in agricultural areas in Brazil

“…Nematode species can be identified by molecular characterization based on sequencing of rDNA subunit (28S)181920, because low morphological variation and similar characteristics within this group hamper identification15. Infectivity, environmental tolerance and suitability for commercial formulations vary between EPN isolates and species2122 which can be used to control pests of various orders, such as Coleoptera232425, Hemiptera2627282930 and Lepidoptera313233.…”