Boosting a Gene Enhances Disease Resistance in Cork Oak Embryos

Jenn Hoskins
22nd August, 2024

Boosting a Gene Enhances Disease Resistance in Cork Oak Embryos

Successful genetic transformation of Cork oak (Quercus suber) was confirmed by selecting kanamycin-resistant explants (a) and observing strong green fluorescent protein (GFP) expression in somatic embryos (b, c), leaves (d), and roots (e), leading to the regeneration of healthy transgenic plantlets (f).

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

Key Findings

  • Researchers at Universidade de Lisboa, Portugal, transferred a gene from chestnut into cork oak to improve its resistance to the pathogen Phytophthora cinnamomi
  • The gene transfer was successful, with 22 independent transgenic cork oak lines showing the presence of the chestnut gene
  • Transgenic cork oaks with the chestnut gene exhibited improved tolerance to Phytophthora cinnamomi compared to non-modified plants
Quercus suber, commonly known as cork oak, is a vital species in the Mediterranean basin, playing a significant role in the region's economy and biodiversity. However, cork oak forests are facing severe threats due to a complex disease known as "oak decline," primarily caused by the pathogen Phytophthora cinnamomi[2]. This decline has led to extensive mortality in cork oak populations, necessitating innovative solutions to mitigate the damage. A recent study conducted by researchers at Universidade de Lisboa, Portugal, explored a promising biotechnological approach to enhance the resilience of cork oak against Phytophthora cinnamomi[1]. The study involved transferring a gene from chestnut, homologous to ginkbilobin-2 (Cast_Gnk2-like), into cork oak somatic embryos. This gene in Ginkgo biloba encodes an antifungal protein, and its introduction into cork oak aimed to improve the tree's tolerance to the harmful pathogen. The transformation process was carried out using Agrobacterium-mediated transformation, a method that allows for the insertion of foreign genes into plant cells. The efficiency of this transformation varied among the different embryogenic lines used, ranging from 2.5% to 9.2%, resulting in 22 independent transgenic lines. The presence of the Cast_Gnk2-like gene in these transgenic embryos was confirmed using Polymerase Chain Reaction (PCR), a technique that amplifies DNA sequences to verify the presence of specific genes. Further analysis using quantitative PCR (qPCR) revealed that the number of transgene copies in the high-proliferation embryogenic lines varied between one and five. The expression levels of the Cast_Gnk2-like gene were also measured, with the highest levels observed in lines derived from the genotype ALM6-WT. This indicates that the genetic background of the cork oak can influence the expression of the introduced gene, a finding consistent with previous studies on genetic transformation in cork oak[3]. The transgenic plants were then subjected to in vitro tolerance tests under controlled conditions. These tests involved treating the plants with zoospores of Phytophthora cinnamomi to evaluate their resistance. The results showed that plants overexpressing the Cast_Gnk2-like gene exhibited improved tolerance compared to wild-type plants. This suggests that the antifungal protein encoded by the chestnut gene can enhance the cork oak's defense mechanisms against the pathogen. This study builds on earlier research that has explored various biotechnological approaches to address oak decline. For instance, somatic embryogenesis, a technique that involves the development of a plant from somatic cells, has been used to propagate and improve genetic traits in cork oak[4]. This method has also been applied to other oak species, like Quercus ilex, to address similar decline issues[5]. The current study's use of genetic transformation to introduce antifungal genes represents a significant advancement in these efforts. Moreover, the study's findings are crucial in the context of climate change, which exacerbates the challenges faced by cork oak forests. Irregular water regimes and prolonged drought periods can weaken trees, making them more susceptible to pathogens like Phytophthora cinnamomi[2]. By enhancing the genetic resistance of cork oak, this biotechnological approach offers a sustainable solution to mitigate the effects of environmental stressors and pathogen attacks. In conclusion, the research conducted by Universidade de Lisboa demonstrates the potential of genetic transformation in improving the resilience of cork oak against Phytophthora cinnamomi. By introducing the Cast_Gnk2-like gene from chestnut, the study provides a promising strategy to combat oak decline and protect the valuable cork oak forests in the Mediterranean basin. This innovative approach, combined with ongoing efforts in somatic embryogenesis and other biotechnological techniques, holds significant promise for the conservation and restoration of these critical ecosystems.

GeneticsBiochemPlant Science

References

Main Study

1) Overexpression of Ginkbilobin-2 homologous domain gene improves tolerance to Phytophthora cinnamomi in somatic embryos of Quercus suber.

Published 21st August, 2024

https://doi.org/10.1038/s41598-024-70272-2

Related Studies

2) Endemic and Emerging Pathogens Threatening Cork Oak Trees: Management Options for Conserving a Unique Forest Ecosystem.

https://doi.org/10.1094/PDIS-03-16-0408-FE

3) Efficient Transformation of Somatic Embryos and Regeneration of Cork Oak Plantlets with A Gene (CsTL1) Encoding a Chestnut Thaumatin-Like Protein.

https://doi.org/10.3390/ijms22041757

4) Vegetative propagation of Quercus suber L. by somatic embryogenesis. I. Factors affecting the induction in leaves from mature cork oak trees.

Journal: Plant cell reports, Issue: Vol 21, Issue 8, Apr 2003

5) Holm Oak Somatic Embryogenesis: Current Status and Future Perspectives.

https://doi.org/10.3389/fpls.2019.00239


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