Tweaking a Protein in a Virus Can Protect Passion Fruit from Infection

Greg Howard
20th June, 2024

Tweaking a Protein in a Virus Can Protect Passion Fruit from Infection

Common passionfruit (Passiflora edulis)

Photo adapted from: Colin Meurk / CC BY SA (Source)

Key Findings

  • Researchers at Hainan University developed three weakened strains of Telosma mosaic virus (TelMV) to protect passion fruit plants
  • These weakened strains can infect passion fruit plants without causing severe symptoms, making them ideal for cross protection
  • Passion fruit plants pre-inoculated with these weakened strains showed strong resistance to severe TelMV infections
Telosma mosaic virus (TelMV) is an emerging threat to passion fruit plantations worldwide, causing significant agricultural losses. Existing control strategies have proven inadequate, necessitating innovative approaches to manage this virus. A recent study conducted by researchers at Hainan University has explored the potential of cross protection, a technique where a mild virus strain pre-infects a plant to protect it from a more severe strain, to combat TelMV[1]. The study focused on the HC-Pro gene, a multifunctional protein in potyviruses that plays a crucial role in viral infection processes, including multiplication, movement, transmission, and RNA silencing suppression. RNA silencing is a defense mechanism in plants that degrades viral RNA to prevent the virus from spreading. By introducing specific point mutations into the conserved motif FRNK of the HC-Pro gene, researchers aimed to create attenuated (weakened) strains of TelMV that could protect passion fruit plants without causing severe symptoms. Three attenuated mutants of TelMV were successfully developed: R181K, R181D, and R181E. These mutants were able to systemically infect passion fruit plants but did not produce noticeable symptoms, making them ideal candidates for cross protection. When passion fruit plants were pre-inoculated with one of these attenuated mutants, they exhibited efficient protection against subsequent infection by a severe TelMV strain. Additionally, the HC-Pros of these mutants showed reduced RNA silencing suppression activity in Nicotiana benthamiana leaves, a common model plant used in virology studies. This research builds on previous findings in the field of cross protection. For example, cross protection has been used to manage Citrus tristeza virus (CTV) in citrus plants by using mild isolates to protect against severe strains[2]. Similarly, attenuated mutants of papaya ringspot virus (PRSV) were developed by mutating specific residues in the HC-Pro gene, resulting in effective protection against severe strains in papaya plants[3]. These studies highlight the potential of manipulating viral genes to create protective strains, a strategy that has now been successfully applied to TelMV. Moreover, the study aligns with earlier efforts to use RNA silencing mechanisms for virus control. For instance, research on Zucchini yellow mosaic virus (ZYMV) demonstrated that mutations in the HC-Pro gene could reduce the virus's ability to suppress RNA silencing, leading to attenuated strains that provided high levels of protection in squash plants[4]. The current study extends these principles to TelMV, offering a new tool for sustainable passion fruit production. In conclusion, the development of attenuated TelMV mutants by Hainan University researchers represents a significant advancement in plant virology and crop protection. By leveraging the concept of cross protection and targeting the HC-Pro gene, this study provides a practical and powerful method to combat TelMV, ensuring the health and productivity of passion fruit plantations.

GeneticsBiochemPlant Science

References

Main Study

1) Mutating the arginine residue within the FRNK motif of telosma mosaic virus (TelMV) HC-Pro protein attenuates viral infection and confers effective protection against TelMV in passion fruit (Passiflora edulis).

Published 19th June, 2024

https://doi.org/10.1002/ps.8252

Related Studies

2) Developing an understanding of cross-protection by Citrus tristeza virus.

https://doi.org/10.3389/fmicb.2013.00076

3) Modification of Papaya Ringspot Virus HC-Pro to Generate Effective Attenuated Mutants for Overcoming the Problem of Strain-Specific Cross Protection.

https://doi.org/10.1094/PDIS-05-22-1130-RE

4) Rapid selection of potyviral cross-protection effective mutants from the local lesion host after nitrous acid mutagenesis.

https://doi.org/10.1111/mpp.13346


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