By Jun Guo
I'm excited to share some groundbreaking research that's been making waves in the world of plant genetic engineering. A team of researchers from diverse fields unveiled the innovative Cut-Dip-Budding (CDB) CRISPR-cas9 construct delivery system, which promises to revolutionize how we modify plants genetically. This method has been published recently in the scientific journal, Innovation and Plant Biotechnology Journal, directed by Dr. Jian-kang Zhu at the Southern University of Science and Technology, China. It is poised to revolutionize research and breeding practices worldwide!
Does tissue culture have to be involved when we do gene modifications?
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Sequences that together with the enzyme Cas9 (CRISPR Associated) is used as a precise gene editing tool in plants. Traditionally, genetic modification technology in plants using CRISPR-cas9 has heavily relied on tissue culture techniques using Agrobacterium tumefaciens, which can be both complex and costly. Tissue culture is a sterile technique where scientists provide plant stem cells or 'explants' with hormones that can regenerate a full plant. However, the CDB delivery system offers a transformative alternative. Rather than relying on labor-intensive tissue culture, this method involves directly inoculating plant explants with the related root transforming bacterium - Agrobacterium rhizogenes.
Here's how it works:
The Cut-Dip-Budding delivery system employs Agrobacterium rhizogenes to deliver the CRISPR-cas9 construct, enabling target gene editing in regenerated roots or shoots. Agrobacterium rhizogenes triggers the formation of transformed roots in plant explants. Subsequently, these transformed roots give rise to transformed buds through a process known as ‘root suckering’ whereby the plant responds to wounding by making adventitious buds that give rise to clonal plants. What's truly remarkable is that this entire process occurs without the need for the elaborate setups and sterile conditions typically associated with tissue culture (Figure 1). In the study by Zhu, the findings suggest that succulents with shoot regeneration ability from cut leaves can be genetically transformed using the CDB method, thus opening up an avenue for genetic engineering of these plants.
Figure 1: Succulents with shoot regeneration ability from cut leaves using the CDB method.
Why is the CDB delivery system revolutionary?
The beauty of the CDB method lies in its simplicity. Rather than navigating through complex protocols, researchers can use a straightforward explant dipping protocol that can be carried out under non-sterile conditions, making the process more accessible and cost-effective. By simplifying the process of genetic modification, this innovative approach accelerates the pace of crop improvement, facilitating the development of resilient, high-yielding varieties tailored to diverse agroecological conditions.
What's particularly exciting is the broad applicability of the CDB method. Researchers have successfully demonstrated its effectiveness across various plant families, including species that were previously challenging to modify genetically. The CDB delivery system helps bypass the major bottleneck in CRISPR applications – gene delivery in non-model plant species.
Final thoughts:
The Cut-Dip-Budding Delivery System represents a monumental leap forward in plant genetic engineering, characterized by its simplicity, accessibility, and effectiveness. As we embrace this new era of precision breeding, the future of crop improvement looks brighter than ever before.
In my own research on Aluminum stress responsive proteins in tomato roots, I find some genes only or mainly express in the roots. If this method works for my system, maybe it can be used to functionally validate several genes likely involved in aluminum tolerance.
References
Cao, X., Xie, H., Song, M., Lu, J., Ma, P., Huang, B., ... & Zhu, J. K. (2023). Cut–dip–budding delivery system enables genetic modifications in plants without tissue culture. The Innovation, 4(1).
Lu, J., Li, S., Deng, S., Wang, M., Wu, Y., Li, M., ... & Zhu, J. K. (2024). A method of genetic transformation and gene editing of succulents without tissue culture. Plant Biotechnology Journal.
Lu, J., Lu, S., Su, C., Deng, S., Wang, M., Tang, H., ... & Zhu, J. K. (2024). Tissue culture-free transformation of traditional Chinese medicinal plants with root suckering capability. Horticulture Research, 11(2), uhad290.
Acknowledgement
This article was written with AI assistance for language editing.
Jun Guo is a final year PhD student at Tennessee State University, specializing in Agricultural Sciences and Engineering. His research is dedicated to developing tomato Aluminum stress-tolerant lines using CRISPR technology. Beyond academia, Jun finds solace in nature through running and hiking.
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