title: Transgenic cotton over-producing spinach sucrose phosphate synthase showed enhanced leaf sucrose synthesis and improved fiber quality under controlled environmental conditions.
abstract: 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.
authors.affiliation: Department of Crop Science and Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7620, USA. candace_haigler@ncsu.edu
authors.forename: Candace H
authors.initials: CH
authors.lastname: Haigler
authors.forename: Bir
authors.initials: B
authors.lastname: Singh
authors.forename: Deshui
authors.initials: D
authors.lastname: Zhang
authors.forename: Sangjoon
authors.initials: S
authors.lastname: Hwang
authors.forename: Chunfa
authors.initials: C
authors.lastname: Wu
authors.forename: Wendy X
authors.initials: WX
authors.lastname: Cai
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hozain
authors.forename: Wonhee
authors.initials: W
authors.lastname: Kang
authors.forename: Brett
authors.initials: B
authors.lastname: Kiedaisch
authors.forename: Richard E
authors.initials: RE
authors.lastname: Strauss
authors.forename: Eric F
authors.initials: EF
authors.lastname: Hequet
authors.forename: Bobby G
authors.initials: BG
authors.lastname: Wyatt
authors.forename: Gay M
authors.initials: GM
authors.lastname: Jividen
authors.forename: A Scott
authors.initials: AS
authors.lastname: Holaday
mesh_terms: D015153:Blotting, Western; D002245:Carbon Dioxide / Q000494:pharmacology; D002250:Carbon Radioisotopes; D032561:Cotton Fiber; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D005964:Glucosyltransferases / Q000235:genetics* / Q000378:metabolism; D003368:Gossypium / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D008027:Light; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018724:Spinacia oleracea / Q000201:enzymology* / Q000235:genetics; D013213:Starch / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism*; D013696:Temperature
chemical_list: D002250:Carbon Radioisotopes; D002245:Carbon Dioxide; D013395:Sucrose; D013213:Starch; D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase