Articles
Regeneration and genetic transformation of two important azalea species in China
Article number
1434_40
Pages
289 – 294
Language
English
Abstract
Azaleas are one of the ten traditionally famous flowers in China and are widely used in landscaping, among which Rhododendron × pulchrum Sweet is the most important one. R. hainanense has beautiful reddish flowers and is resistant to heat and water.
Due to its narrow distribution area, it is listed as a vulnerable species on the IUCN Red List of endangered species.
Although there are plenty of azalea cultivars, most cannot be used in urban environments due to being susceptible to various abiotic stresses.
Genetic transformation is an effective means of introducing desired traits into good-looking cultivars.
There has been some research on the micropropagation of azaleas since the 1980s, but their transgenic systems are still lacking.
Based on optimizing the protocols for regeneration via the callus phase or directly from explants of R. × pulchrum and R. hainanense, we used stems and leaves as explants, tested Anderson medium with different concentrations of Zeatin and 2, 4-d, and finally established the callus induction method of R. hainanense. The callus induction rate was up to 88%. We also developed the best callus induction method of R.×pulchrum through Anderson medium with the optimal concentration of Zeatin and NAA and using the sterile leaves of R. × pulchrum as explants.
The callus induction rate was over 90%. Then, the GUS gene was transformed by the Agrobacterium-mediated transgene system.
Both callus and shootlets turned blue after the gus assay.
The present callus genetic transformation methods will provide a crucial tool for breeding, gene function analysis, and bioengineering research in azaleas.
Due to its narrow distribution area, it is listed as a vulnerable species on the IUCN Red List of endangered species.
Although there are plenty of azalea cultivars, most cannot be used in urban environments due to being susceptible to various abiotic stresses.
Genetic transformation is an effective means of introducing desired traits into good-looking cultivars.
There has been some research on the micropropagation of azaleas since the 1980s, but their transgenic systems are still lacking.
Based on optimizing the protocols for regeneration via the callus phase or directly from explants of R. × pulchrum and R. hainanense, we used stems and leaves as explants, tested Anderson medium with different concentrations of Zeatin and 2, 4-d, and finally established the callus induction method of R. hainanense. The callus induction rate was up to 88%. We also developed the best callus induction method of R.×pulchrum through Anderson medium with the optimal concentration of Zeatin and NAA and using the sterile leaves of R. × pulchrum as explants.
The callus induction rate was over 90%. Then, the GUS gene was transformed by the Agrobacterium-mediated transgene system.
Both callus and shootlets turned blue after the gus assay.
The present callus genetic transformation methods will provide a crucial tool for breeding, gene function analysis, and bioengineering research in azaleas.
Authors
H. Zhou, Z. Li, B. Liu, X. Wang, Y. Xia
Keywords
micropropagation, callus induction, transgene, Rhododendron hainanense, Rhododendron × pulchrum
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