The smORF-containing gene mille-pattes is required for moulting and Trypanosoma cruzi metacyclogenesis in the Chagas disease vector Rhodnius prolixus

Abstract

SummaryChagas disease is estimated to affect 8 million people worldwide and is responsible for approximately 10,000 deaths in Latin America every year. Control of the triatomine bugs that transmit the flagellated parasite Trypanosoma cruzi has been the most successful strategy to avoid disease spread. Genes containing small open reading frames (smORFs, < 100 amino acids) constitute a putative reservoir of new vector control targets, since hundreds of these genes are present in insect genomes. Here, we show that the prototypic smORF-containing gene mille-pattes/polished-rice/tarsalless (mlpt/pri/tal) is essential for postembryonic development of the kissing bug Rhodnius prolixus and for T. cruzi metacyclogenesis during the nymphal stages. Injection of double-stranded RNA against mlpt (Rp-dsmlpt) during the nymphal stages leads to a plethora of phenotypes, which impair postembryonic development. First, fourth or fifth stage nymphs injected with Rp-dsmlpt do not moult even in the presence of the ecdysone receptor (EcR) mRNA. Second, Rp-dsmlpt nymphs have defects in gut morphology, delayed haemoglobin digestion, and decreased defecation volume compared with those of the control nymphs. Third, Rp-mlpt knockdown inhibits T. cruzi differentiation to the trypomastigote infective stage (metacyclogenesis) inside the R. prolixus gut. Overall, our study is the first to provide evidence that a smORF-containing gene regulates vector physiology and parasitic cycle thus enabling the development of novel molecular strategies to eliminate Chagas disease transmission.