Identification of a putative Mexican strain of Serratia entomophila pathogenic against root-damaging larvae of Scarabaeidae (Coleoptera).
The larvae of scarab beetles, known as "white grubs" and belonging to the genera Phyllophaga and Anomala (Coleoptera: Scarabaeidae), are regarded as soil-dwelling pests in Mexico. During a survey conducted to find pathogenic bacteria with the potential to control scarab larvae, a native Serratia sp. (strain Mor4.1) was isolated from a dead third-instar Phyllophaga blanchardi larva collected from a cornfield in Tres Marías, Morelos, Mexico. Oral bioassays using healthy P. blanchardi larvae fed with the Mor4.1 isolate showed that this strain was able to cause an antifeeding effect and a significant loss of weight. Mortality was observed for P. blanchardi, P. trichodes, and P. obsoleta in a multidose experiment. The Mor4.1 isolate also caused 100% mortality 24 h after intracoelomic inoculation of the larvae of P. blanchardi, P. ravida, Anomala donovani and the lepidopteran insect Manduca sexta. Oral and injection bioassays were performed with concentrated culture broths of the Mor4.1 isolate to search for disease symptoms and mortality caused by extracellular proteins. The results have shown that Mor4.1 broths produce significant antifeeding effects and mortality. Mor4.1 broths treated with proteinase K lost the ability to cause disease symptoms and mortality, in both the oral and the injection bioassays, suggesting the involvement of toxic proteins in the disease. The Mor4.1 isolate was identified as a putative Serratia entomophila Mor4.1 strain based on numerical taxonomy and phylogenetic analyses done with the 16S rRNA gene sequence. The potential of S. entomophila Mor4.1 and its toxins to be used in an integrated pest management program is discussed.
Nuñez-Valdez
M Eugenia
ME
Facultad de Ciencias Agropecuarias, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C. P. 62210, Cuernavaca, Mor., Mexico. eugenia@uaem.mx
Calderón
Marco A
MA
Aranda
Eduardo
E
Hernández
Luciano
L
Ramírez-Gama
Rosa M
RM
Lina
Laura
L
Rodríguez-Segura
Zitlhally
Z
Gutiérrez
María del C
Mdel C
Villalobos
Francisco J
FJ
D000818:Animals; D015373:Bacterial Typing Techniques; D001522:Behavior, Animal; D001517:Coleoptera / Q000254:growth & development* / Q000382:microbiology*; D005247:Feeding Behavior; D007814:Larva / Q000382:microbiology; D008800:Mexico; D008969:Molecular Sequence Data; D010572:Pest Control, Biological; D010641:Phenotype; D018517:Plant Roots / Q000469:parasitology*; D017422:Sequence Analysis, DNA; D012705:Serratia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*