De Novo Analysis of the Transcriptome of Meloidogyne enterolobii to Uncover Potential Target Genes for Biological Control.

Xiangyang Li,Heng Jian,Dan Yang,Jianlong Zhao,Junhai Niu

doi:10.3390/ijms17091442

Abstract

Meloidogyne enterolobii is one of the obligate biotrophic root-knot nematodes that has the ability to reproduce on many economically-important crops. We carried out de novo sequencing of the transcriptome of M. enterolobii using Roche GS FLX and obtained 408,663 good quality reads that were assembled into 8193 contigs and 31,860 singletons. We compared the transcripts in different nematodes that were potential targets for biological control. These included the transcripts that putatively coded for CAZymes, kinases, neuropeptide genes and secretory proteins and those that were involved in the RNAi pathway and immune signaling. Typically, 75 non-membrane secretory proteins with signal peptides secreted from esophageal gland cells were identified as putative effectors, three of which were preliminarily examined using a PVX (pGR107)-based high-throughput transient plant expression system in Nicotiana benthamiana (N. benthamiana). Results showed that these candidate proteins suppressed the programmed cell death (PCD) triggered by the pro-apoptosis protein BAX, and one protein also caused necrosis, suggesting that they might suppress plant immune responses to promote pathogenicity. In conclusion, the current study provides comprehensive insight into the transcriptome of M. enterolobii for the first time and lays a foundation for further investigation and biological control strategies.

Highlights

Meloidogyne enterolobii (M. enterolobii) is an important obligate biotrophic plant parasite, infestation of which can lead to yellowing and stunting as a result of the nutritional and water stress caused by the physical root damage of nematode feeding [2]
The objective of the current research was to systematically study the transcriptome of M. enterolobii and to determine the possible mechanism of pathology of M. enterolobii in plants, as well as any important genes that might be used as RNA interference (RNAi) targets for biological control
Transcriptome sequencing of M. enterolobii generated 408,663 reads, for a total of 165,040,879 base pairs, with an average length of 403 bp, of which 355,760 reads were assembled into 8193 contigs with an average length of 1202 bp

Summary

Introduction

These nematodes can negatively affect host plants in three main ways: damaging the plant roots, competing for nutrients and causing infection from other microbes induced by root damage [1]. M. enterolobii can infect a variety of host plants, including economic crops, such as cotton, pepper, tobacco and watermelon [2,4], and has become a potential threat to the agricultural economy in tropical and subtropical areas. A PCR-based detection method can be used to identify M. enterolobii accurately [5]. There is no effective way of controlling M. enterolobii. Biological control is considered an ideal alternative to the chemical methods, such as RNA interference (RNAi). Detailed knowledge of the suitable target genes of M. enterolobii for such control strategies is still absent [8]

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Results