Identifying Virulence-Associated Genes Using Transcriptomic and Proteomic Association Analyses of the Plant Parasitic Nematode Bursaphelenchus mucronatus

Abstract

Bursaphelenchus mucronatus (B. mucronatus) isolates that originate from different regions may vary in their virulence, but their virulence-associated genes and proteins are poorly understood. Thus, we conducted an integrated study coupling RNA-Seq and isobaric tags for relative and absolute quantitation (iTRAQ) to analyse transcriptomic and proteomic data of highly and weakly virulent B. mucronatus isolates during the pathogenic processes. Approximately 40,000 annotated unigenes and 5000 proteins were gained from the isolates. When we matched all of the proteins with their detected transcripts, a low correlation coefficient of r = 0.138 was found, indicating probable post-transcriptional gene regulation involved in the pathogenic processes. A functional analysis showed that five differentially expressed proteins which were all highly expressed in the highly virulent isolate were involved in the pathogenic processes of nematodes. Peroxiredoxin, fatty acid- and retinol-binding protein, and glutathione peroxidase relate to resistance against plant defence responses, while β-1,4-endoglucanase and expansin are associated with the breakdown of plant cell walls. Thus, the pathogenesis of B. mucronatus depends on its successful survival in host plants. Our work adds to the understanding of B. mucronatus’ pathogenesis, and will aid in controlling B. mucronatus and other pinewood nematode species complexes in the future.

Selection of Reliable Reference Genes for RT-qPCR Analysis of Bursaphelenchus mucronatus Gene Expression From Different Habitats and Developmental Stages

“…The FAR protein accelerates the absorption and transportation of fatty acids and retinoids, helping nematodes to infect the host and inhibit the host defenses ( Basavaraju et al, 2003 ). Previous reports demonstrated that FAR expression increased when the nematodes infected and colonized host trees ( Cheng et al, 2013 ; Zhou L. et al, 2016 ). Employing the most suitable gene combination ( TUB / 18S rRNA / UBCE ) to normalize FAR expression under the two habitat conditions, we were able to demonstrate that the expression of the gene significantly increased when the nematodes were inoculated into pine trees.…”

“…Eight candidate reference genes were selected which had previously been reported to be suited to transcript normalization in other organisms under different experimental conditions. The sequences of candidate reference genes were obtained from the transcriptome de novo assembly sequences of B. mucronatus ( Zhou L. et al, 2016 ). Primers were designed using Primer Premier 5 software (Premier Biosoft International, Palo Alto, CA, United States), according to the SYBR Green Master Mix (Vazyme, Nanjing, China) manufacturer’s instructions.…”

“…With the development of biotechnology, increasing biological data of B. mucronatus including transcriptome ( Yan et al, 2012 ; Zhou L. et al, 2016 ) and proteome ( Cardoso et al, 2016 ; Zhou L. et al, 2016 ) were available. Furthermore, the expression profiles and functions of some genes in this nematode had been investigated, such as heat shock protein genes ( Huang et al, 2009 ; Dai et al, 2011 ), cathepsin gene ( Pan et al, 2015 ), fatty acid- and retinol-binding protein gene ( Zhou L. et al, 2016 ), expansin gene ( Zhou L. et al, 2016 ), cellulase gene ( Wang et al, 2017 ), and so on. It shows urgent need to select reference genes for B. mucronatus under different experimental conditions.…”

The role of mab‐3 in spermatogenesis and ontogenesis of pinewood nematode, Bursaphelenchus xylophilus

“…Thus, our results are in accord with the large number of previous studies that employed the J2 for RNAi. [40][41][42] Small body size genes (sma) were firstly identified in Sydney Brenner's classic screen by the relative decrease of nematode body size in C. elegans. 43 Subsequently, the much more direct way, genetic screen was exploited for isolation of sma.…”

Comparative Transcriptome Analysis of Pinus densiflora Following Inoculation with Pathogenic (Bursaphelenchus xylophilus) or Non-pathogenic Nematodes (B. thailandae)

“…Many studies have been carried out to find ways to diagnose and block PWD, and most of them have been focused on B. xylophilus and its beetle vectors 9–11 . Currently, to diagnose PWD, B. xylophilus or DNA fragments from B. xylophilus must be detected in tree samples 12 , or PWD symptoms must be observed.…”