Lasting consequences of psyllid (Bactericera cockerelli L.) infestation on tomato defense, gene expression, and growth

Kyle Harrison,Julien Gad Levy,Cecilia Tamborindeguy,Azucena Mendoza-Herrera

doi:10.1186/s12870-021-02876-z

Kyle Harrison, Julien Gad Levy + Show 2 more

Open Access

https://doi.org/10.1186/s12870-021-02876-z

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Abstract

BackgroundThe tomato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae), is a pest of solanaceous crops such as tomato (Solanum lycopersicum L.) in the U.S. and vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’. Currently, the only effective strategies for controlling the diseases associated with this pathogen involve regular pesticide applications to manage psyllid population density. However, such practices are unsustainable and will eventually lead to widespread pesticide resistance in psyllids. Therefore, new control strategies must be developed to increase host-plant resistance to insect vectors. For example, expression of constitutive and inducible plant defenses can be improved through selection. Currently, it is still unknown whether psyllid infestation has any lasting consequences on tomato plant defense or tomato plant gene expression in general.ResultsIn order to characterize the genes putatively involved in tomato defense against psyllid infestation, RNA was extracted from psyllid-infested and uninfested tomato leaves (Moneymaker) 3 weeks post-infestation. Transcriptome analysis identified 362 differentially expressed genes. These differentially expressed genes were primarily associated with defense responses to abiotic/biotic stress, transcription/translation, cellular signaling/transport, and photosynthesis. These gene expression changes suggested that tomato plants underwent a reduction in plant growth/health in exchange for improved defense against stress that was observable 3 weeks after psyllid infestation. Consistent with these observations, tomato plant growth experiments determined that the plants were shorter 3 weeks after psyllid infestation. Furthermore, psyllid nymphs had lower survival rates on tomato plants that had been previously psyllid infested.ConclusionThese results suggested that psyllid infestation has lasting consequences for tomato gene expression, defense, and growth.

Highlights

The tomato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae), is a pest of solanaceous crops such as tomato (Solanum lycopersicum L.) in the U.S and vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’
The psyllid is native to the Southwestern U.S and Northern Mexico [12, 49, 55, 64] but has only recently become an important agricultural pest when it was discovered that B. cockerelli vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’ (Lso) [43]
The current study focuses on an insect-plant relationship, the experiments described are informed by Lso disease development

Summary

Introduction

The tomato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae), is a pest of solanaceous crops such as tomato (Solanum lycopersicum L.) in the U.S and vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’. The only effective strategies for controlling the diseases associated with this pathogen involve regular pesticide applications to manage psyllid population density. Disease transmission can be disrupted by manipulating the host or vector’s genes associated with key molecular pathways that facilitate the movement of pathogens from host to vector and vice versa [1, 32]. Such genetic manipulations can be accomplished through direct transformations or artificial selection, but these toolkits require certain a priori genomic information. In order to pursue psyllid control strategies that manipulate the host plant’s molecular pathways, the current study identifies the genes involved in the transcriptomic response of tomato plants to psyllid infestation

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Conclusion