title: Pathogenicity of Isolates of Serratia Marcescens towards Larvae of the Scarab Phyllophaga Blanchardi (Coleoptera).
abstract: Serratia marcescens is a Gram negative bacterium (Enterobacteriaceae) often associated with infection of insects. In order to find pathogenic bacteria with the potential to control scarab larvae, several bacterial strains were isolated from the hemocoel of diseased Phyllophaga spp (Coleoptera:Scarabaeidae) larvae collected from cornfields in Mexico. Five isolates were identified as Serratia marcescens by 16S rRNA gene sequencing and biochemical tests. Oral and injection bioassays using healthy Phyllophaga blanchardi larvae fed with the S. marcescens isolates showed different degrees of antifeeding effect and mortality. No insecticidal activity was observed for Spodoptera frugiperda larvae (Lepidoptera: Noctuidae) by oral inoculation. S. marcescens (Sm81) cell-free culture supernatant caused significant antifeeding effect and mortality to P. blanchardi larvae by oral bioassay and also mortality by injection bioassay. Heat treated culture broths lost the ability to cause disease symptoms, suggesting the involvement of proteins in the toxic activity. A protein of 50.2 kDa was purified from the cell-free broth and showed insecticidal activity by injection bioassay towards P. blanchardi. Analysis of the insecticidal protein by tandem- mass spectrometry (LC-MS/MS) showed similarity to a Serralysin-like protein from S. marcescens spp. This insecticidal protein could have applications in agricultural biotechnology.
authors.affiliation: Centro de Investigación en Dinámica Celular, Instituto de Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, CP 62209, Cuernavaca, Morelos, Mexico. mlpc@uaem.mx.
authors.forename: Mónica L
authors.initials: ML
authors.lastname: Pineda-Castellanos
authors.affiliation: Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. zit.rodriguez@gmail.com.
authors.forename: Zitlhally
authors.initials: Z
authors.lastname: Rodríguez-Segura
authors.affiliation: El Colegio de la Frontera Sur, Carretera Panamericana y Periférico Sur s/n Barrio María Auxiliadora, CP 29290, San Cristóbal de Las Casas, Chiapas, Mexico. fvillalobos@ecosur.mx.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Villalobos
authors.affiliation: Facultad de Química, Universidad Nacional Autónoma de Mexico, Mexico D.F., Mexico. lhergom@unam.mx.
authors.forename: Luciano
authors.initials: L
authors.lastname: Hernández
authors.affiliation: Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, 62209, Cuernavaca, Morelos, Mexico. llina@uaem.mx.
authors.forename: Laura
authors.initials: L
authors.lastname: Lina
authors.affiliation: Centro de Investigación en Dinámica Celular, Instituto de Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, CP 62209, Cuernavaca, Morelos, Mexico. eugenia@uaem.mx.
authors.forename: M Eugenia
authors.initials: ME
authors.lastname: Nuñez-Valdez
keywords: Phyllophaga; Serratia marcescens; biological control; insecticidal protein; pathogenicity; scarab; serralysin; white grub