Abstract

GARCIA RAMIREZ, Alejandro; REYES RAMIREZ, Arturo; RUIZ SANCHEZ, Esaú  and  IBARRA, Jorge E.. Isolated native Bacillus thuringiensis from southeastern Mexico. Rev. Mex. Cienc. Agríc [online]. 2018, vol.9, n.3, pp.539-551. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v9i3.1213.

In order to find native isolates of Bacillus thuringiensis, in the present work isolations were made from different materials obtained from the southeast of Mexico, in the period from March 2014 to July 2015. Bacterial colonies were selected based on the typical characteristics of the Bacillus genus and were identified as Bacillus thuringiensis, based on the presence of parasporal crystals, cry gene, hag gene, protein profile and insecticidal activity. An isolate of soil samples (ITCBT34) and two larvae of Chlosyne lacinia (ITCBT61, ITCBT62) was obtained. These isolates presented amplification of the cry and hag genes. Isolate ITCBT34 presented crystals with oval morphology, while isolates ITCBT61 and ITCCBT62 presented dipyramidal crystals. Differences were observed in the size of the fragment produced by the amplification of the hag gene and in the protein profile of the different isolates. The insecticidal activity was determined by crude bioassay with a concentration of 10 μg cm-2. The three isolates caused 100% mortality of Manduca sexta larvae at 96 h of exposure. Isolates ITCBT61 and ITCBT62 showed morphological characteristics and size of the hag gene similar to the reference strain B. thuringiensis svar. kurstaki HD1, the isolate ITCBT34 showed no similarity, so it could be an isolate not related to serovar kurstaki HD1.

Keywords : Chlosyne lacinia; Manduca sexta; gene cry; gene hag.

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