Open AccessCo‐expression of Arabidopsis transcription factor, At MYB 12 , and soybean isoflavone synthase, Gm IFS 1 , genes in tobacco leads to enhanced biosynthesis of isoflavones and flavonols resulting in osteoprotective activity
Author(s) -
Pandey Ashutosh,
Misra Prashant,
Khan Mohd P.,
Swarnkar Gaurav,
Tewari Mahesh C.,
Bhambhani Sweta,
Trivedi Ritu,
Chattopadhyay Naibedya,
Trivedi Prabodh K.
Publication year - 2014
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12118
Subject(s) - biology , myb , isoflavones , transgene , genistein , arabidopsis , ovariectomized rat , formononetin , transcription factor , genetically modified crops , biochemistry , gene , genetics , hormone , mutant , daidzein
Summary Isoflavones, a group of flavonoids, restricted almost exclusively to family Leguminosae are known to exhibit anticancerous and anti‐osteoporotic activities in animal systems and have been a target for metabolic engineering in commonly consumed food crops. Earlier efforts based on the expression of legume isoflavone synthase ( IFS ) genes in nonlegume plant species led to the limited success in terms of isoflavone content in transgenic tissue due to the limitation of substrate for IFS enzyme. In this work to overcome this limitation, the activation of multiple genes of flavonoid pathway using Arabidopsis transcription factor At MYB 12 has been carried out. We developed transgenic tobacco lines constitutively co‐expressing At MYB 12 and Gm IFS 1 (soybean IFS ) genes or independently and carried out their phytochemical and molecular analyses. The leaves of co‐expressing transgenic lines were found to have elevated flavonol content along with the accumulation of substantial amount of genistein glycoconjugates being at the highest levels that could be engineered in tobacco leaves till date. Oestrogen‐deficient (ovariectomized, Ovx) mice fed with leaf extract from transgenic plant co‐expressing At MYB 12 and Gm IFS 1 but not wild‐type extract exhibited significant conservation of trabecular microarchitecture, reduced osteoclast number and expression of osteoclastogenic genes, higher total serum antioxidant levels and increased uterine oestrogenicity compared with Ovx mice treated with vehicle (control). The skeletal effect of the transgenic extract was comparable to oestrogen‐treated Ovx mice. Together, our results establish an efficient strategy for successful pathway engineering of isoflavones and other flavonoids in crop plants and provide a direct evidence of improved osteoprotective effect of transgenic plant extract.