Transgenic Cotton Over-Producing Spinach Sucrose Phosphate Synthase Showed Enhanced Leaf Sucrose Syntheis and Improved Fiber Quality Under Controlled Environmental Conditions




Holaday, A.Scott
Jividen, Gay M.
Wyatt, Bobby G.
Hequet, Eric F.
Strauss, Richard E.
Kiedaisch, Brett
Kang, Wonhee
Hozain, Mohamed
Cai, Wendy X.
Wu, Chunfa

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Springer Verlag


Prior data indicated that enhanced availability of sucrose, a major product of photosynthesis in source leaves and the carbon source for secondary wall cellulose synthesis in fiber sinks, might improve fiber quality under abiotic stress conditions. To test this hypothesis, a family of transgenic cotton plants (Gossypium hirsutum cv. Coker 312 elite) was produced that over-expressed spinach sucrose-phosphate synthase (SPS) because of its role in regulation of sucrose synthesis in photosynthetic and heterotrophic tissues. A family of 12 independent transgenic lines was characterized in terms of foreign gene insertion, expression of spinach SPS, production of spinach SPS protein, and development of enhanced extractable Vmax SPS activity in leaf and fiber. Lines with the highest Vmax SPS activity were further characterized in terms of carbon partitioning and fiber quality compared to wild-type and transgenic null controls. Leaves of transgenic SPS over-expressing lines showed higher sucrose:starch ratio and partitioning of 14C to sucrose in preference to starch. In two growth chamber experiments with cool nights, ambient CO2 concentration, and limited light below the canopy, the transgenic line with the highest SPS activity in leaf and fiber had higher fiber micronaire and maturity ratio associated with greater thickness of the cellulosic secondary wall.




Haigler C. H., B. Singh, D. Zhang, S. Hwang, C. Wu, X. Cai, M. Hozain, W. Kang, B. Kiedaisch, R. Strauss, E. Hequet, B. Wyatt, G. Jividen, S. Holaday. 2007. Transgenic cotton over-producing spinach phosphate synthase showed enhanced leaf sucrose synthesis and improved fiber quality under controlled environmental conditions, Plant Molecular Biology, 63.6 (2007):815-832.