Effects of Sorghum halepense, an alternative food source, on the metatranscriptome and transcriptome of Spodoptera frugiperda, a major maize pest.

MARÍA MICAELA CASTRO; NATALIA A. CABRERA; EDUARDO G. VIRLA; *CHRISTINA B. MCCARTHY

Chacras de Coria

Congreso; X Congreso Argentino de Entomología; 2018

Sociedad Argentina de Entomología

Spodoptera frugiperda (OrdenLepidoptera, Familia Noctuidae) has a broad geographical distribution (fromArgentina to southern USA), and is one of the pests that causes most harm tomaize crops in Argentina. It is mainly controlled with transgenic corn andchemical insecticides, but their inadequate use has led to field-evolvedresistance. For this reason there is a compelling need to develop alternativecontrol strategies. In this regard, it is widely accepted that insects derivetheir microbiota from the surrounding environment, and that it can influence itslife cycle. Moreover, an inventory of the associated microbiota, especially ofwild specimens, would aid in understanding their biology more comprehensively,and in developing novel biocontrol strategies. We previously captured S.frugiperda specimens from different environments, altitudes and foodsources in the province of Tucumán (Argentina). Total RNA was extracted fromfifth instar larval guts, submitted to a one-step reverse transcription and PCRsequence independent amplification procedure, and then pyrosequenced. In thisstudy we analysed one of these samples, namely, larvae that were captured froman alternative food source, Sorghumhalepense, in El Manantial locality (26°49´50´´S, 65°16´59.4´´W; LulesDepartment, Tucumán Province) at 495 meters above sea level. Sequence readswere trimmed and assembled. Homology searches were performed against variousNCBI databases. Taxonomic and functional contents were analysed with MEGAN.Sequences from the metatranscriptome showed homology to the Domains Bacteriaand Eukarya, among which we found potential biocontrol agents. On the otherhand, analysis of the host gene expression profile showed that most transcriptswere associated with three biological functions: cellular processes and cellcycle, environmental stress and resistance to xenobiotics, and biosynthesis.Among these, various transcripts represent possible targets for pest control via RNA interference (RNAi). Inconclusion, this study has enabled a comprehensive view of the potentialeffects of this alternative food source (i.e.,Sorghum halepense) and theenvironmental conditions, on the S. frugiperda larval gut transcriptome, the associated metatranscriptome, andthe interactions between them.