Inside the gut: Revelations of metatranscriptomic and transcriptomic analyses of Spodoptera frugiperda larvae from an organic maize plantation at 2283 meters above sea level (Tafí del Valle, Tucumán).

GASTÓN ROZADILLA; 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 is a noctuid moththat devastates various crops, including corn, and is found in most of theAmerican continent. Transgenic crops that produce insecticidal proteins from Bacillus thuringiensis are currently themost successful biotechnological pest management application, but S. frugiperda has developedfield-evolved resistance. In this regard, insect gut microbiota conform acomplex community that establishes symbiotic relationships with its host,contributing to its viability. For this reason, metatranscriptomic andtranscriptomic analyses of insect guts in their natural environment areinvaluable to better comprehend their biology and to identify genes as targetsfor pest control. We previously captured S. frugiperda specimens fromdifferent environments, altitudes and food sources in the province of Tucumán(Argentina). For all samples, total RNA extracted from fifth instar larval gutswas submitted to a one-step reverse transcription and PCR sequence independentamplification procedure, and then pyrosequenced. In this study we analysed oneof these samples, namely, larvae that were captured in an organic maize fieldin Tafí del Valle (26°55´40.75´´S, 65°45´19.90´´W; Tucumán province) at 2283meters above sea level. Sequence reads were trimmed and assembled. Homologysearches were performed against various NCBI databases. Taxonomic andfunctional contents were analysed with MEGAN. The metatranscriptome, in whichwe identified sequences from archaea, bacteria, fungi, nematodes and plants,revealed potential biocontrol candidates for this pest, and others related withhost metabolism and digestion. Furthermore, the host transcriptome showed thatmost transcripts were associated with the digestive tract structure anddevelopment, among others. Some of these genes could be possible targets forpest control via RNA interference(RNAi). In summary, this study has shown the potential effects of thisparticular food source (i.e., organicmaize) and of the environmental conditions (altitude, among others), on theexpression profile of S. frugiperda larval guts, their associated metatranscriptome,and putative interactions between them. Future studies will test the potentialbiocontrol candidates that we identified.