CTV-T36 Vectors as a Tool to Induce Efficient Flowering in Citrus Seedlings
Posted August 2025
Researchers: Choaa El Mohtar, Manjul Dutt
Contact: Choaa El Mohtar, UF/IFAS CREC mohtarc@ufl.edu
Summary:
Citrus breeding is limited by the extensive time required for new crosses to become mature enough to enable another round of crosses, and the time needed for new rootstocks to produce seed for production. We are working on a system to induce more efficient flowering in different genotypes of 1-1.5-year-old citrus seedlings by using the CTV vector to overexpress or downregulate a gene of interest either independently or simultaneously. Flowering would be followed by the removal of the virus by alternating temperature treatment. We constructed a first prototype of a CTV vector expressing the FT3 gene, which efficiently induced flowers in a few months in citrus; however, the construct was unstable and did not induce flowers in all varieties. We currently have a second prototype in which we changed the position of insertion of FT3, making the vector more stable; thus, inducing flowering more efficiently in Citrus macrophylla seedlings for a longer period of time. We also used the second prototype CTV vector to induce flowering in a CRISPR-modified sweet orange that is supposedly tolerant to HLB. We are currently working on a system that combines transgenic plants with CTV vectors to generate a more robust system of inducing flowering in more citrus genotypes. Such a system would allow CRISPR-modified citrus plants to reach maturity faster and aid the rapid integration of tolerance/ resistance from citrus relatives into elite citrus lines, enabling the development of permanent resistance/tolerance in a few years rather than the century needed by traditional breeding.
Take Home Message:
- CTV is being used as a tool to induce early flowering in citrus seedlings.
- CTV would be eliminated from mature tissue by alternate temperature treatment.
- Working on combining CTV vector with transgenic plants to have a more efficient system to induce flowering
