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Somatic embryogenesis and transformation of cassava for enhanced starch production

Ihemere, Uzoma Enyinnaya
http://rave.ohiolink.edu/etdc/view?acc_num=osu1070549008

Abstract Details

2003, Doctor of Philosophy, Ohio State University, Horticulture and Crop Science.
Cassava (Manihot esculenta Crantz), a member of the family Euphorbiaceae, is one of the most important food crops of sub-Saharan Africa. One of the constraints for cassava starch production is the long growing season. Cassava typically takes 9-12 months to yield a good harvest. This is longer than other major starch-producing crops such as corn and potatoes. We report here the generation of transgenic cassava with increased starch biosynthesis capacity. This was achieved by enhancing the activity of ADP-glucose pyrophosphorylase (AGPase), the rate-limiting enzyme in the starch biosynthesis, in transgenic cassava. To do this, we transformed cassava with a modified E. coli glgC gene encoding AGPase. The glgC gene was modified by site-directed mutagenesis (K296E/G336D) to remove the allosteric regulation (enhancement by fructose1,6-P and inhibition by AMP) sites and to increase the velocity of the enzyme. Root-specific expression of the glgC gene product was achieved using the tuber-specific patatin promoter of potato. We obtained antibiotic-resistant putative transformed plants which have been shown to have integrated and expressed the transgene by PCR, Southern blot, RT-PCR and enzyme activity analyses. AGPase enzyme activity in transformed plants was increased by more than 65%. Significantly, transgenic plants expressing the bacterial glgC gene had two-fold greater top (leaf and stem) and root biomass than wild-type plants grown in the greenhouse.
Richard Sayre (Advisor)
184 p.
cassava; ADP-glucose pyrophosphorylase; starch; somatic embryogenesis; transformation

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Citations

  • Ihemere, U. E. (2003). Somatic embryogenesis and transformation of cassava for enhanced starch production [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1070549008

    APA Style (7th edition)

  • Ihemere, Uzoma. Somatic embryogenesis and transformation of cassava for enhanced starch production. 2003. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1070549008.

    MLA Style (8th edition)

  • Ihemere, Uzoma. "Somatic embryogenesis and transformation of cassava for enhanced starch production." Doctoral dissertation, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1070549008

    Chicago Manual of Style (17th edition)

osu1070549008
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© 2003, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.