A transcriptomic snapshot of early molecular communication between Pasteuria penetrans and Meloidogyne incognita

Abstract

BackgroundSouthern root-knot nematode Meloidogyne incognita (Kofoid and White, 1919), Chitwood, 1949 is a key pest of agricultural crops. Pasteuria penetrans is a hyperparasitic bacterium capable of suppressing the nematode reproduction, and represents a typical coevolved pathogen-hyperparasite system. Attachment of Pasteuria endospores to the cuticle of second-stage nematode juveniles is the first and pivotal step in the bacterial infection. RNA-Seq was used to understand the early transcriptional response of the root-knot nematode at 8 h post Pasteuria endospore attachment.ResultsA total of 52,485 transcripts were assembled from the high quality (HQ) reads, out of which 582 transcripts were found differentially expressed in the Pasteuria endospore encumbered J2 s, of which 229 were up-regulated and 353 were down-regulated. Pasteuria infection caused a suppression of the protein synthesis machinery of the nematode. Several of the differentially expressed transcripts were putatively involved in nematode innate immunity, signaling, stress responses, endospore attachment process and post-attachment behavioral modification of the juveniles. The expression profiles of fifteen selected transcripts were validated to be true by the qRT PCR. RNAi based silencing of transcripts coding for fructose bisphosphate aldolase and glucosyl transferase caused a reduction in endospore attachment as compared to the controls, whereas, silencing of aspartic protease and ubiquitin coding transcripts resulted in higher incidence of endospore attachment on the nematode cuticle.ConclusionsHere we provide evidence of an early transcriptional response by the nematode upon infection by Pasteuria prior to root invasion. We found that adhesion of Pasteuria endospores to the cuticle induced a down-regulated protein response in the nematode. In addition, we show that fructose bisphosphate aldolase, glucosyl transferase, aspartic protease and ubiquitin coding transcripts are involved in modulating the endospore attachment on the nematode cuticle. Our results add new and significant information to the existing knowledge on early molecular interaction between M. incognita and P. penetrans.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5230-8) contains supplementary material, which is available to authorized users.

Effect of fluensulfone on different functional genes of root-knot nematode Meloidogyne incognita

“…Around 5,000 J2s were used for each replication. Following soaking, total RNA was extracted from the J2s with NucleoSpin RNA kit (Macherey-Nagel, Düren, Germany) according to manufacturer’s protocol as described previously ( Phani et al, 2018 ). The RNA was treated with RQ1 RNase-Free DNase (Promega, Madison, WI, USA) to get rid of any genomic DNA contamination.…”

“…Quantitative real-time PCR (qRT PCR) was carried out to analyze the expression pattern of the genes in M. incognita J2s after exposing them against fluensulfone. The qRT PCR was performed in a Realplex2 thermal cycler (Eppendorf, Hamburg, Germany) using SYBR Green Supermix Kit (Eurogentec, Liege, Belgium) ( Phani et al, 2018 ). Reaction mixture for each sample contained a final volume of 10 µL comprising of 5 µL of SYBR Green PCR Master mix, 750 nM of each primers and 1.5 ng of cDNA.…”