Transgenic cotton over-producing spinach sucrose phosphate synthase showed enhanced leaf sucrose synthesis and improved fiber quality under controlled environmental conditions

• Published in: Plant molecular biology Vol. 63; no. 6; pp. 815 - 832
• Main Authors: Haigler, Candace H, Singh, Bir, Zhang, Deshui, Hwang, Sangjoon, Wu, Chunfa, Cai, Wendy X, Hozain, Mohamed, Kang, Wonhee, Kiedaisch, Brett, Strauss, Richard E, Hequet, Eric F, Wyatt, Bobby G, Jividen, Gay M, Holaday, A Scott
• Format: Journal Article
• Language: English
• Published: Netherlands Springer Nature B.V 01.04.2007
• Subjects: Blotting, Western; Carbon Dioxide - pharmacology; Carbon Radioisotopes; Carbon sources; Cellulose; Cotton; Cotton Fiber; Environmental conditions; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - radiation effects; Glucosyltransferases - genetics; Glucosyltransferases - metabolism; Gossypium - genetics; Gossypium - growth & development; Gossypium - metabolism; Growth chambers; Leaves; Light; Photosynthesis; Plant Leaves - genetics; Plant Leaves - growth & development; Plant Leaves - metabolism; Plants, Genetically Modified; Reverse Transcriptase Polymerase Chain Reaction; Spinacia oleracea; Spinacia oleracea - enzymology; Spinacia oleracea - genetics; Starch; Starch - metabolism; Sucrose; Sucrose - metabolism; Temperature; Vegetables
• ISSN: 0167-4412; 1573-5028
• DOI: 10.1007/s11103-006-9127-6

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 V (max) SPS activity in leaf and fiber. Lines with the highest V (max) 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 (14)C to sucrose in preference to starch. In two growth chamber experiments with cool nights, ambient CO(2) 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.