Assessing the Pathogenicity of Two Bacteria Isolated from the Entomopathogenic Nematode <i>Heterorhabditis indica</i> against <i>Galleria mellonella</i> and Some Pest Insects

oleh: Rosalba Salgado-Morales, Fernando Martínez-Ocampo, Verónica Obregón-Barboza, Kathia Vilchis-Martínez, Alfredo Jiménez-Pérez, Edgar Dantán-González

Format: Article
Diterbitkan: MDPI AG 2019-03-01

Deskripsi

The entomopathogenic nematodes <i>Heterorhabditis</i> are parasites of insects and are associated with mutualist symbiosis enterobacteria of the genus <i>Photorhabdus</i>; these bacteria are lethal to their host insects. <i>Heterorhabditis indica</i> MOR03 was isolated from sugarcane soil in Morelos state, Mexico. The molecular identification of the nematode was confirmed using sequences of the ITS1-5.8S-ITS2 region and the D2/D3 expansion segment of the 28S rRNA gene. In addition, two bacteria HIM3 and NA04 strains were isolated from the entomopathogenic nematode. The genomes of both bacteria were sequenced and assembled de novo. Phylogenetic analysis was confirmed by concatenated gene sequence datasets as <i>Photorhabdus luminescens</i> HIM3 (16S rRNA, 23S rRNA, <i>dnaN</i>, <i>gyrA</i>, and <i>gyrB</i> genes) and <i>Pseudomonas aeruginosa</i> NA04 (16S rRNA, 23S rRNA and <i>gyrB</i> genes). <i>H. indica</i> MOR03 infects <i>Galleria mellonella</i>, <i>Tenebrio molitor</i>, <i>Heliothis subflexa</i>, and <i>Diatraea magnifactella</i> larvae with LC50 values of 1.4, 23.5, 13.7, and 21.7 IJs/cm<sup>2</sup>, respectively, at 48 h. These bacteria are pathogenic to various insects and have high injectable insecticide activity at 24 h.