High Red-Blue Light Ratio Promotes Accelerated In Vitro Flowering and Seed-Set Development in Amaranthus...

Area of Science:

• Plant Biotechnology
• Molecular Biology
• Agricultural Science

Background:

• Grain amaranths exhibit significant recalcitrance to conventional in vitro regeneration methods like organogenesis and somatic embryogenesis.
• Achieving floral organogenesis, a crucial developmental stage, is rarely successful in vitro for these species.

Purpose of the Study:

• To overcome regeneration recalcitrance in grain amaranth by exploring in vitro flowering manipulation.
• To establish an efficient and reproducible in vitro protocol for generating fully developed Amaranthus hypochondriacus plants.

Main Methods:

• Utilized half-longitudinally dissected zygotic embryos for plant generation.
• Employed high-irradiance LED illumination with a 3:1 red-blue ratio to induce flowering under long-day conditions.
• Analyzed gene expression patterns of flowering-related genes and ribosome biogenesis/seed development genes.

Main Results:

• Achieved a 70% rate of early flowering under long-day photoperiods using specific red-blue LED light; white LED light did not induce flowering.
• All in vitro flowering plants produced viable seeds.
• Observed upregulation of key flowering genes (CONSTANS, FLOWERING LOCUS T, LEAFY) and downregulation of TERMINAL FLOWER1.
• Identified differential expression of ribosome biogenesis and seed development genes.

Conclusions:

• Specific red-blue LED light is critical for inducing in vitro flowering and seed production in Amaranthus hypochondriacus.
• A proposed model highlights the role of light-regulated molecular mechanisms involving key flowering genes and protein synthesis in this process.
• This protocol offers a viable strategy for regenerating recalcitrant grain amaranth varieties.