Abstract
BackgroundIn hyperspecialized parasites, the ability to grow on a particular host relies on specific virulence factors called effectors. These excreted proteins are involved in the molecular mechanisms of parasitism and distinguish virulent pathogens from non-virulent related species. The potato cyst nematodes (PCN) Globodera rostochiensis and G. pallida are major plant-parasitic nematodes developing on numerous solanaceous species including potato. Their close relatives, G. tabacum and G. mexicana are stimulated by potato root diffusate but unable to establish a feeding site on this plant host.ResultsRNA sequencing was used to characterize transcriptomic differences among these four Globodera species and to identify genes associated with host specificity. We identified seven transcripts that were unique to PCN species, including a protein involved in ubiquitination. We also found 545 genes that were differentially expressed between PCN and non-PCN species, including 78 genes coding for effector proteins, which represent more than a 6-fold enrichment compared to the whole transcriptome. Gene polymorphism analysis identified 359 homozygous non-synonymous variants showing a strong evidence for selection in PCN species.ConclusionsOverall, we demonstrated that the determinant of host specificity resides in the regulation of essential effector gene expression that could be under the control of a single or of very few regulatory genes. Such genes are therefore promising targets for the development of novel and more sustainable resistances against potato cyst nematodes.
Highlights
In hyperspecialized parasites, the ability to grow on a particular host relies on specific virulence factors called effectors
The aims of this study were to characterize the transcriptomic differences between four Globodera species exposed to potato root diffusate and to identify genes putatively involved in host specificity, using RNA sequencing to look at changes in gene expression and genetic variation between populations
The percentage of reads that successfully mapped to the G. rostochiensis reference transcriptome was on average 79.4% for G. rostochiensis, 74.2% for G. pallida, 69.3% for G. tabacum and 56.1% for G. mexicana
Summary
The ability to grow on a particular host relies on specific virulence factors called effectors. Sabeh et al BMC Genomics (2019) 20:457 process and are highly dependent on their set of specific secreted proteins called effectors, used by PPNs to manipulate the host to their benefit [10] These effectors are responsible for most of the interactions with their host and given their importance in the infection mechanisms, substantial research efforts have been put on these molecules in recent years [11]. It has been shown that effector genes contain a greater proportion of non-synonymous mutations compared to other genes [14] To better understand this relationship, a formal comparison of genetic variation between closely related species having different host ranges would help to identify elements that are associated with host specificity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
