Research and Development

Core technology :  CRES-T

The CRES-T, “Chimeric REpressor gene Silencing Technology”, is a novel gene silencing technology, which is a powerful tool for gene manipulation in commercially important plant traits.
Transcription factors (TFs) are key regulators for the control of various plant phenomena. However, redundancy of genes often interferes with manipulation and functional analysis of TFs. Conventional gene silencing technology (Anti-sense RNA, RNAi, and overexpression of a TF faulted method) is not sufficient to overcome this problem.

What are advantages in CRES-T system?
Effective to functionally redundant TFs.
Chimeric repressor suppresses expression of the target genes dominantly over the activation
   activity of endogenous and functionally redundant transcription factors with resultant phenotypes
   that are similar to those from loss-of-function mutants in CRES-T system.

Easy manipulation.
   Although genetic information is necessary to design a vector construct for RNAi, we do not need
   any information of genetic sequences in CRES-T system. A chimeric repressor is just made by
   adding a sequence of repression domain to your target TFs.

Possible to find novel phenotypes.
Expression of chimeric repressors induce various interesting phenotypes that have been
   not  observed by conventional gene silencing technology (Fig.1).

Broad application to various species of plants.
   CRES-T system functions not only in dicots, such as Arabidopsis but also monocots,Rice.
   We can apply CRES-T system to various plant species for production of desirable plants.

Fig.1: CRES-T induces various interesting phenotypes.


Which services can we provide for you?
Chimeric repressor library is available

   We have prepared seed pools from transgenic Arabidopsis lines that respectively express the
   chimeric repressor for each of the transcription factors encoded in Arabidopsis genome. The

   “chimeric repressor library
is now available at GreenSogna for research and development
   collaborations to identify traits of interest and for functional genomics to third party academic and
   commercial partners.

Screening of useful traits of plants
   GreenSogna is identifying chimeric repressors that are useful for the improvement of many
   commercially important plant traits, including such complex traits as environmental stress
   resistance. Using its proprietary Arabidopsis
chimeric repressor library for 2000 transcription
   factors, the company can rapidly identify transformed plants which exhibit the phenotype of
   interest and then characterize the chimeric repressor that delivers the trait. So far, the company
   is identifying chimeric repressors that confer such traits as tolerance to hormones and various
   environmental stresses. Furthermore, GreenSogna is applying these chimeric repressors into
   various plant species such as rice, tobacco, poplar and flowers etc.

Tolerance to abiotic stress and the herbicide

 Responding to global climate change and global warming, GreenSogna is identifying chimeric repressors that confer tolerance to various stresses such as, high osmotic stress, salinity condition, high temperature, and herbicides (Fig.2). Those chimeric repressors are being applied to crops to improve the yields.


Fig.2: Control of abiotic stress tolerance and herbicide resistance

Control of fertility

 Male and female sterile plants are particularly useful for the effective production of commercial hybrid plants and for preventing the diffusion of seeds or pollen grains of genetically modified plants in the open field. Greesogna has identified several chimeric repressors that cause male and female fertility of monocots and dicots (Fig.3). These genes are being used to prevent the productivity of a number of crop species in addition to plants used for biofuels.

Fig.3: Control of fertility

Control of lignin and cellulose biosynthesis

 By manipulation of NST genes, we are able to produce plants, which have low or high contents of lignin (Fig.4). These would be useful for effective production of biofuel and bioenergy. These genes are being used to apply for poplar and eucalyptus used for biofuel.

Fig.4: Control of lignin and cellulose biosynthesis

Manipulation of Flowers, Horticultural plant, grass and crops

Manipulation of flower traits
GreenSogna is applying chimeric repressors into various species of plants (Fig.5). GreenSogna demonstrated that our CRES-T system is a powerful tool to manipulate morphology of flowers by CRES-T system. Transgenic plants expressing chimeric repressor showed ethylene insensitive in Arabidopsis and suppression of etiolation with aging in Chrysanthemum (Unpublished data).
For example, Sansevieria trifasciata is popular for ornamental plant in the world and it is that improves indoor air quality by removing aero-toxins such as formaldehyde. We trust to be able to enhance these functions by CRES-T system for more comfortable living.
Changing metabolic pathway in Brassica
CRES-T allows us to enhance a secondary metabolite production by changing metabolic pathway in plants.GreenSogna has identified chimeric repressors which confer increased contents of protein in transgenic seeds. We also succeeded to isolate chimeric repressors which enhance seed oil contents up to 130% of that of wild-type average (Unpublished data). Theses chimeric repressors are being introduced into Brassica for effective biofuel production.
Rice for biofuel materials
GreenSogna is also preparing various CRES-T lines in rice. GreenSogna has investigated CRES-T rice showing low lignin / high suger content for application to biofuel materials. And we have some possible candidates showing high saccharification rate.

Application to grass and other crops

In Other useful crops, GreenSogna is now developing CRES-T lines and high efficiency transformation system. Brachypodium distachyon (L.) is a new model plant for functional genomics studies in grasses and cereals. Brachypodium has many advantages for accelerating of monocot research: it has small genome size, dwarf, self-fertility, short lifecycle, and simple growth requirement ( GreenSogna trying to construct CRES-T lines of Brachypodium for advanced researches of grasses and cereals.



Fig.5: GreenSogna is applying chimeric repressors into various species of plants

 Finally, CRES-T system is a powerful tool for functional analysis of redundant plant transcription factors
and the manipulation of useful traits in various plant species.
This system is completely different from simple overexpression and conventional gene silencing  technology.
 Therefore, we can provide many important plant traits and contribute to agricultural and 
industrial developments in the world.