Testing How Okra Leaf Curl Virus Genes Activate in Various Plants

Greg Howard
13th May, 2024

Testing How Okra Leaf Curl Virus Genes Activate in Various Plants

Image Source: Natural Science News, 2024

Key Findings

  • Researchers from the University of Delhi found that okra virus promoters can boost gene expression in plants
  • The Rep promoter from the okra virus was more effective than another promoter and a commonly used standard
  • These promoters also increased activity when plants were infected with the virus, especially in cotton
In recent years, the field of plant biotechnology has been exploring novel ways to enhance gene expression in transgenic plants. One promising avenue is the use of viral promoters, which are segments of DNA that control the initiation of gene transcription. Researchers from the University of Delhi have made a significant contribution to this area by investigating the promoters from the okra enation leaf curl virus (OELCuV), a begomovirus that affects okra plants[1]. This study could potentially offer new tools for plant genetic engineering by providing alternative promoters for gene expression. The team focused on two specific promoters from OELCuV: the Rep promoter, which initiates the replication-associated protein gene, and the CP promoter, responsible for starting the coat protein gene. These were fused with the green fluorescent protein (GFP) reporter gene, which serves as a visual marker to track gene expression. The promoters were then introduced into okra, cotton, and Nicotiana benthamiana—a commonly used model plant in laboratory studies. To quantify the activity of these promoters, the researchers employed confocal laser scanning microscopy and GFP assays. The results revealed that the Rep promoter was more active than the CP promoter, and the latter showed similar activity levels to the well-known CaMV 35S promoter, a widely used standard in plant biotechnology. This finding is particularly exciting as it suggests that the Rep promoter from OELCuV could be a stronger alternative to the CaMV 35S promoter for driving gene expression in certain plants. Moreover, the study also demonstrated that both the Rep and CP promoters experienced an increase in expression levels when the plants were inoculated with OELCuV and betasatellite DNAs, particularly in cotton plants. This suggests that these promoters can be transactivated, meaning they can be switched on by other viral proteins, which could be an advantage in creating more efficient gene expression systems. These findings align with previous studies on begomoviruses, which have also shown that viral promoters can be highly effective in regulating gene expression in plants[2][3][4]. For instance, the bipartite begomovirus BleICV was found to have a unique coat protein gene promoter that could be useful in understanding the transcriptional regulation of viral genes[5]. Similarly, the bidirectional promoter of the Cotton leaf curl Burewala virus (CLCuBuV) was shown to strongly regulate the transcription of two genes in opposite orientations[3][4]. These studies collectively demonstrate the potential of viral promoters as tools in plant biotechnology. The methodology used in the University of Delhi's study is a testament to the power of modern biotechnological approaches, which include the use of reporter genes like GFP to visually assess gene expression and the use of confocal microscopy to quantify promoter activity. These techniques allow for precise measurement and comparison of promoter strength, which is crucial for identifying the best candidates for use in genetic engineering applications. The study's findings are not only important for the basic understanding of viral gene regulation but also have practical implications. The discovery of new, potent promoters like the OELCuV Rep promoter provides researchers with more options for designing transgenic plants with enhanced or specialized traits. For instance, these promoters could be used to drive expression of genes that confer resistance to pests or diseases, improve crop yield, or enable plants to cope with environmental stresses. In conclusion, the work conducted by the University of Delhi offers valuable insights into the transcriptional regulation of begomovirus genes and expands the toolbox of promoters available for plant biotechnology. By demonstrating the effectiveness of the OELCuV promoters, particularly the Rep promoter, this study paves the way for further research and development in the field of transgenic plant design and opens up new possibilities for improving crop performance through genetic engineering.

BiotechGeneticsPlant Science

References

Main Study

1) Transient expression analysis of promoters of okra enation leaf curl virus in Nicotiana benthamiana, cotton and okra plants.

Published 10th May, 2024

https://doi.org/10.1007/s11262-024-02074-7

Related Studies

2) Identification and validation of promoters and cis-acting regulatory elements.

https://doi.org/10.1016/j.plantsci.2013.12.007

3) Functional characterization of a bidirectional plant promoter from cotton leaf curl Burewala virus using an Agrobacterium-mediated transient assay.

https://doi.org/10.3390/v6010223

4) Functional characterization of a strong bi-directional constitutive plant promoter isolated from cotton leaf curl Burewala virus.

https://doi.org/10.1371/journal.pone.0121656

5) Analysis of a new begomovirus unveils a composite element conserved in the CP gene promoters of several Geminiviridae genera: Clues to comprehend the complex regulation of late genes.

https://doi.org/10.1371/journal.pone.0210485


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