Brassinolide improves embryogenic tissue initiation in conifers and rice

Area of Science:

• Plant Biotechnology
• Forestry
• Plant Physiology

Background:

• Somatic embryogenesis (SE) is crucial for mass-producing high-value coniferous trees.
• Commercial SE requires success across diverse genotypes, but initiation can be recalcitrant in species like loblolly pine.
• Brassinolide, a plant growth regulator, influences various plant developmental processes.

Purpose of the Study:

• To investigate the efficacy of brassinolide in improving somatic embryogenesis initiation in loblolly pine, Douglas-fir, and Norway spruce.
• To assess brassinolide's impact on embryogenic tissue weight and its ability to overcome genotypic recalcitrance.

Main Methods:

• Supplementation of culture media with brassinolide at concentrations from 0.005-0.25 micro M.
• Comparison of initiation percentages between control and brassinolide-treated media (0.1 micro M).
• Detailed formulation of a modified medium including specific salts, activated carbon, micronutrients, sugars, amino acids, and plant growth regulators.

Main Results:

• Brassinolide significantly improved SE initiation percentages in loblolly pine (15.0% to 30.1%), Douglas-fir (16.1% to 36.3%), and Norway spruce (34.6% to 47.4%).
• Brassinolide increased loblolly pine embryogenic tissue weight by 66%.
• The plant growth regulator stimulated initiation in recalcitrant families, mitigating genotypic differences.

Conclusions:

• Brassinolide is effective in enhancing somatic embryogenesis initiation across diverse coniferous species and genotypes.
• The optimized medium, including brassinolide, shows promise for commercial-scale propagation of valuable forest trees.
• Brassinolide application can help overcome genetic barriers in SE, contributing to more sustainable forestry practices.