Gene Activity Changes in Different Life Stages of Potato Pest

Greg Howard
16th July, 2024

Gene Activity Changes in Different Life Stages of Potato Pest

A robust correlation was found between the expression of the recA gene (a) and the density of Candidatus Liberibacter solanacearum in its potato psyllid (Bactericera cockerelli) vector and tomato host, establishing it as a reliable internal control for the study's gene expression analyses over the less correlated 16S rRNA gene (b).

Image adapted from: Saberi et al. / CC BY (Source)

Key Findings

  • The study by The University of Arizona focused on how "Ca. Liberibacter solanacearum" (CLso) interacts with the potato psyllid and tomato plants
  • Researchers found that the expression of specific genes in CLso varies depending on whether it is in the psyllid or the tomato plant
  • Certain genes related to bacterial adhesion and invasion are regulated differently in the psyllid at various developmental stages compared to the tomato plant
Psyllid species, including the potato psyllid (PoP) Bactericera cockerelli, serve as vectors for "Candidatus Liberibacter spp." ("Ca. Liberibacter"), which infects various plant hosts like citrus and tomato. These bacteria are transmitted in a circulative and propagative manner, meaning they circulate within the vector and multiply before being passed on to the plant. Understanding the interactions between these bacteria and their hosts is crucial for developing effective management strategies. A recent study by researchers at The University of Arizona delved into the interaction between "Ca. Liberibacter solanacearum" (CLso) and its host, the potato psyllid, to uncover how these bacteria manage to infect both the insect vector and the tomato plant[1]. The study focused on examining the expression of specific genes and loci in CLso that are believed to play key roles in bacterial adhesion, invasion, pathogenicity, and motility. These genes were analyzed using real-time quantitative reverse transcriptase amplification (qRT-PCR) from RNA isolated from CLso-infected psyllids at various developmental stages (1st-2nd nymphs, 4th-5th nymphs, and teneral adults) and from CLso-infected tomato plants. This approach allowed the researchers to quantify the relative expression of these genes and understand how they vary depending on the host and the developmental stage of the psyllid. Earlier studies have shown that CLso is transmitted by the potato psyllid through a circulative and propagative route, where the bacteria form biofilms and invade various tissues of the psyllid, including the midgut and salivary glands[2]. This systemic invasion is crucial for the bacteria to multiply and be transmitted to plants. The current study builds on this knowledge by investigating how specific genes associated with these processes are regulated during different stages of the psyllid's life cycle and in the tomato plant. One of the key findings of the study is that the expression of these genes is host-dependent and varies with the developmental stage of the psyllid. For instance, loci associated with repressor-anti-repressor regulation, which are known to maintain the lysogenic cycle in "Ca. Liberibacter asiaticus" (CLas) in the Asian citrus psyllid Diaphorina citri, were expressed in CLso-infected psyllids but not in CLso-infected tomato plants. This suggests that the regulatory mechanisms of CLso may differ between its insect vector and plant host, potentially influencing the efficiency of bacterial transmission[3]. The study also found that certain genes associated with prophage elements, which are viral DNA segments integrated into the bacterial genome, were expressed differently in the psyllid and tomato plant hosts. In the tomato plant, CLso infection did not lead to the replication of prophage elements SC1-SC2, indicating a possible suppression of these elements in the plant host. This finding is significant as it highlights the complex interactions between CLso and its hosts, which could be targeted for developing novel control strategies. Previous research has emphasized the importance of understanding vector biology and host-pathogen interactions to manage diseases like Zebra chip, caused by CLso[4]. This new study provides deeper insights into the molecular mechanisms underlying these interactions, offering potential targets for disrupting the transmission of CLso. For example, by identifying genes that are crucial for bacterial adhesion and invasion, it may be possible to develop RNA interference (RNAi) strategies to knock down these genes in the psyllid vector, thereby reducing the transmission of CLso[5]. In summary, the study by The University of Arizona researchers sheds light on the complex interactions between CLso and its psyllid and plant hosts, revealing host-dependent gene expression patterns that are crucial for bacterial transmission. By understanding these molecular mechanisms, new strategies can be developed to manage diseases caused by CLso, ultimately benefiting agricultural industries affected by these pathogens.

AgricultureGeneticsPlant Science

References

Main Study

1) Differential expression of "Candidatus Liberibacter solanacearum" genes and prophage loci in different life stages of potato psyllid.

Published 15th July, 2024

https://doi.org/10.1038/s41598-024-65156-4

Related Studies

2) Colonization and Intrusive Invasion of Potato Psyllid by 'Candidatus Liberibacter solanacearum'.

Journal: Phytopathology, Issue: Vol 107, Issue 1, Jan 2017

3) Host and environmental factors influencing 'Candidatus Liberibacter asiaticus' acquisition in Diaphorina citri.

https://doi.org/10.1002/ps.5060

4) Aspects of pathogen genomics, diversity, epidemiology, vector dynamics, and disease management for a newly emerged disease of potato: zebra chip.

https://doi.org/10.1094/PHYTO-09-12-0238-RVW

5) Comparison of potato and asian citrus psyllid adult and nymph transcriptomes identified vector transcripts with potential involvement in circulative, propagative liberibacter transmission.

https://doi.org/10.3390/pathogens3040875


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