Molecular Identification and Phylogenetic Diversity of Native Entomopathogenic Nematodes, and Their Bacterial Endosymbionts, Isolated from Banana and Plantain Crops in Western Colombia

Abstract

With the increasing negative impacts of food production worldwide caused by pests, the recovery of native entomopathogenic nematodes (EPNs) is relevant, since they are adapted to local environments, entomofauna, and significant virulence. Therefore, the present study was designed to recover and understand the phylogenetic diversity of EPNs and their associated bacterial endosymbionts, from banana and plantain crops, as alternatives for the control of weevil species. An extensive sampling of western Colombia covered 325 ha, yielding the recovery of three EPNs’ isolates (0.49% of the samples). The molecular characterization included four mitochondrial and nuclear loci, which, after merging with the sequences of 48 species, confirmed the presence of Steinernema carpocapsae, the first report of S. costaricense in South America, and monophyly in most of the Steinernema clades. The tree topologies were consistent for the nuclear loci but not for mitochondrial, probably due to the high nucleotide substitution rate, deficit in the number of species available for these loci, and incomplete lineage sorting. The endosymbiotic bacteria associated with S. carpocapsae were identified as Xenorhabdus nematophila. However, the S. costaricense bacterial symbiont presented a genetic similarity to X. koppenhoeferi and X. khoisanae, which are still uncertain in their classification. The identification of S. costaricense in South America indicates the wide range distribution of this species in the Americas and its ability to persist in different soil types. For the first time, EPN isolation and phylogenetic characterization are directed to plantain and banana crops. Leveraging EPNs’ diversity promises novel applications for crop protection, while the genetic resources from the bacterial endosymbionts may provide metabolites with a wide spectrum of uses, either for agricultural or medicinal purposes.

Phylogenetic Diversity, Host Specificity, and Distribution of the Wood-Decaying Fungus Phellinotus teixeirae in Western Colombia’s Seasonally Dry Tropical Forest

“…For P. teixeirae, the nucleotide variation was very low between our isolates and previous reports, despite the new host interactions with Pithecellobium dulce. These contrasting outcomes have been identified in eukaryotic genomes [59][60][61][62][63], particularly coupled with considerable variation in gene copy number at rDNA loci in fungal species [57,58,64,65] and intragenomic variation at these loci [58,64,65]. The dynamics of these variations complicate the analysis of rDNA amplicons, being a critical factor for species delimitation, especially for microbial communities in heterogeneous environments [6].…”

Abiotic Stress Tolerance Boosted by Genetic Diversity in Plants

“…Tolerances to abiotic stresses have typically been regarded as complex quantitative traits conferring adaptation [6]. In other words, in contrast with biotic resistances [7,8], abiotic responses recruit more infinitesimal effects across hundreds and thousands of variants [9]. This type of polygenic model has two broad implications when it comes to addressing the adaptive potential of plant species, and its inheritance [10,11].…”

Systematics and phylogeny of the entomopathogenic nematobacterial complexes Steinernema–Xenorhabdus and Heterorhabditis–Photorhabdus

“…close to X. stockiae [ 154 ] S. lamjungense - S. minutum X. stockiae [ 155 ] S. longicaudum X. ehlersii [ 92 ] S. nepalense - S. pui - S. ritteri - S. taiwanensis - S. sasonense - S. ashiuense monticola X. hominicki [ 156 ] S. scapterisci X. innexi [ 92 ] S. borjomiense - S. siamkayai X. stockiae [ 94 ] S. changbaiense - S. surkhetense Xenorhabdus sp. close to X. stockiae [ 157 ] S. monticolum X. hominickii [ 94 ] S. tami - S. robustispiculum - S. costaricense costaricense close to X. koppenhoeferi and X. khoisanae [ 158 ] S. schliemanni close to X. hominickii [ 159 ] S. scarabaei X. koppenhoeferi [ 94 ] ...…”