Interestingly, while transplastomic production of astaxanthin in tobacco by tapping the endogenous chloroplast isoprenoid pathway saw accumulation primarily of the free form , in transplastomic lettuce, mainly the esterified form accumulated the work highlights the potential for production and accumulation of different (or differentially modified) metabolites in chloroplasts by exploring various host species. In the course of this work, we have engineered the biochemical pathway for the high-value ketocarotenoid astaxanthin into chloroplasts of n tabacum and subsequently mobilized the pathway via horizontal genome transfer across graft junctions to obtain transplastomic plants of the tree tobacco, n glauca. Since astaxanthin was not sequestrated by esterification, this non-native pigment may be specifically recruited into photosynthetic pigment–protein complexes as is the case for non-native capsanthin and capsorubin in transfected tobacco leaves (kumagai et al, 1998.
After all genes of the astaxanthin pathway had been implanted into the chloroplast genome, the tobacco plants shows a characteristic orange coloring due to the massive production of the colorant in the chloroplasts. Metabolic engineering of astaxanthin production in tobacco chloroplasts the plant journal 55, 857–868 tomohisa hasunuma, shin-ichi miyazawa, satomi yoshimura, yuki shinzaki, ken-ichi tomizawa, kazutoshi shindo, seon-kang choi, norihiko misawa and chikahiro miyake(2008.
Production in tobacco flowers varda mann 1 , mark harker 1,2 , iris pecker 1 , and joseph hirschberg 1 1 department of genetics, the life sciences institute, the hebrew university of jerusalem, jerusalem, 91904 israel. Although the carotenoid composition of chloroplasts is relatively invariant, a wide range of different carotenoids can be found in chromoplasts: lycopene in tomato fruits, β metabolic engineering of astaxanthin production in tobacco flowers nat biotechnol 2000 18: 888-892 view in article scopus (151). As a result, the transplastomic tobacco yielded astaxanthin at 55 mg/g in leaves however, plastid transformation is applicable only for a few model plants, making it difficult to copy the efficient pathway to plant tissues rich in chromoplasts and carotenoids for economical production of astaxanthin.
In the present study, we have overcome this problem, and have succeeded in producing more than 05% (dry weight) astaxanthin (more than 70% of total caroteniods) in tobacco leaves, which turns their green color to reddish brown, by expressing both genes encoding crtw (beta-carotene ketolase) and crtz (beta-carotene hydroxylase) from a marine bacterium brevundimonas sp, strain sd212, in the chloroplasts. The availability of over 800 sequenced chloroplast genomes from a variety of land plants has enhanced our understanding of chloroplast biology, intracellular gene transfer, conservation, diversity, and the genetic basis by which chloroplast transgenes can be engineered to enhance plant agronomic traits or to produce high-value agricultural or biomedical products.
Read biosynthesis of astaxanthin in tobacco leaves by transplastomic engineering, the plant journal on deepdyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips. As plastid genetic engineering has the potential to confer high levels of protein accumulation in transformants (viitannen et al, 2004), the overproduction of the ketocarotenoids, including astaxanthin, in transplastomic tobacco plants could be achieved by a greater enhancement of both crtz and crtw activities.
Different enzymes from bacteria or fungi, namely β-1,4-endoglucanase, beta glucosidase, swollenin, esterase, cutinase, endoglucanases, exoglucanase, pectate lyases, xylanase, lipase, acetyl, acetyl xylan esterase and xylan were expressed in tobacco chloroplasts for production of fermentable sugars [107 – 111.