Trichostatin A Induced Microspore Embryogenesis and Promoted Plantlet Regeneration in Ornamental Kale (Brassica oleracea var. acephala)

Abstract

Cut flower ornamental kale (Brassica oleracea var. acephala) is a biennial cultivar, which completes a sexual reproductive generation in two years. Isolated microspore culture (IMC) can accelerate plant homozygosity instead of self-pollinations. However, the application of IMC in cut flower ornamental kale was rare since its low rate of embryogenesis. It is proved that histone acetylation might affect the gene expression in microspores and led to the transformation of microspores from pollen development pathway to embryogenesis. In this paper, microspores, derived from three varieties of cut flower ornamental kale, Crane Bicolor (CB), Crane Pink (CP) and Crane Feather Queen (CFQ), were treated with histone deacetylation inhibitor (HDACI) trichostatin A (TSA). Results revealed that the appropriate concentration of TSA was 10 nM for CB with obtaining 5.39 embryos per bud, while for CP and CFQ was 5 nM with acquiring 10.89 and 16.99 embryos per bud, respectively. TSA treatment also reduced the embryonic mortality, of which 10 nM TSA treatments CB was the optimal and the embryonic mortality decreased to 25.01%. The double haploid (DH) proportion of regenerated plants reached 37.3%. These results contribute to improving the technology for IMC in cut flower ornamental kale.