Transgenic cotton over-producing spinach sucrose phosphate synthase showed enhanced leaf sucrose synthesis and improved fiber quality under controlled environmental conditions.
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.
Haigler
Candace H
CH
Department of Crop Science and Department of Plant Biology, North Carolina State University, Raleigh, NC 27695-7620, USA. candace_haigler@ncsu.edu
Singh
Bir
B
Zhang
Deshui
D
Hwang
Sangjoon
S
Wu
Chunfa
C
Cai
Wendy X
WX
Hozain
Mohamed
M
Kang
Wonhee
W
Kiedaisch
Brett
B
Strauss
Richard E
RE
Hequet
Eric F
EF
Wyatt
Bobby G
BG
Jividen
Gay M
GM
Holaday
A Scott
AS
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
D002250:Carbon Radioisotopes; D002245:Carbon Dioxide; D013395:Sucrose; D013213:Starch; D005964:Glucosyltransferases; C022698:sucrose-phosphate synthase