Methods for genetic transformation in Dendrobium

Abstract

The genetic transformation of Dendrobium orchids will allow for the introduction of novel colours, altered architecture and valuable traits such as abiotic and biotic stress tolerance. The orchid genus Dendrobium contains species that have both ornamental value and medicinal importance. There is thus interest in producing cultivars that have increased resistance to pests, novel horticultural characteristics such as novel flower colours, improved productivity, longer flower spikes, or longer post-harvest shelf-life. Tissue culture is used to establish clonal plants while in vitro flowering allows for the production of flowers or floral parts within a sterile environment, expanding the selection of explants that can be used for tissue culture or genetic transformation. The latter is potentially the most effective, rapid and practical way to introduce new agronomic traits into Dendrobium. Most (69.4 %) Dendrobium genetic transformation studies have used particle bombardment (biolistics) while 64 % have employed some form of Agrobacterium-mediated transformation. A singe study has explored ovary injection, but no studies exist on floral dip transformation. While most of these studies have involved the use of selector or reporter genes, there are now a handful of studies that have introduced genes for horticulturally important traits.

Identification and analysis of genes associated with the synthesis of bioactive constituents in Dendrobium officinale using RNA-Seq

“…The Dendrobium genus of plants, the second largest genus in the Orchidaceae, are medicinal herbs with high commercial value in China and other Asian countries 1, 2 . Dendrobium officinale L., an endangered and rare orchid in the wild, has been used as folk medicine for immune regulatory for hundreds of years in China.…”

Building a Genetic Manipulation Tool Box for Orchid Biology: Identification of Constitutive Promoters and Application of CRISPR/Cas9 in the Orchid, Dendrobium officinale

“…The EHA105 A. tumifaciens strain was provided by Takara Biomedical Technology and the pCambia1301-35SN is kindly provided by Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences. The transformation protocol used for the Dendrobium orchid was developed by previous study (Men et al, 2003; da Silva et al, 2011; Hsing et al, 2016; Phlaetita et al, 2015; da Silva et al, 2016). …”

“…We focused on two: overexpression of exogenous genes in the host and silencing of endogenous genes of the host. To achieve overexpression, many reports have published methods for introducing exogenous genes into various Orchidaceae species by bombardment or Agrobacterium -mediated transformation (Yu et al, 2001; Mishiba et al, 2005; Lu et al, 2007; Zhang et al, 2010; da Silva et al, 2011, 2016; Hsing et al, 2016; Phlaetita et al, 2015). To achieve gene silencing, just a few reports showed RNAi-mediated gene knock-down in Dendrobium Sonia (Liu et al, 2014) and Oncidium hybrid orchid (Liu et al, 2014).…”

African violet (Saintpaulia ionantha H. Wendl.): classical breeding and progress in the application of biotechnological techniques

“…Genetic modification of ornamental plants is an important means of introducing new characters such as modified flower colour, leaf shape or plant architecture (Teixeira da Silva et al 2016b). The technology for genome editing has progressed considerably in recent years, and using techniques such as CRISPR/Cas9 (Samanta et al 2016) it is now possible to knock out a specific gene or to target a specific position on the genome for genetic modification.…”