Transcriptome profiling, molecular biological, and physiological studies reveal a major role for ethylene in cotton fiber cell elongation.
Upland cotton (Gossypium hirsutum) produces the most widely used natural fibers, yet the regulatory mechanisms governing fiber cell elongation are not well understood. Through sequencing of a cotton fiber cDNA library and subsequent microarray analysis, we found that ethylene biosynthesis is one of the most significantly upregulated biochemical pathways during fiber elongation. The 1-Aminocyclopropane-1-Carboxylic Acid Oxidase1-3 (ACO1-3) genes responsible for ethylene production were expressed at significantly higher levels during this growth stage. The amount of ethylene released from cultured ovules correlated with ACO expression and the rate of fiber growth. Exogenously applied ethylene promoted robust fiber cell expansion, whereas its biosynthetic inhibitor l-(2-aminoethoxyvinyl)-glycine (AVG) specifically suppressed fiber growth. The brassinosteroid (BR) biosynthetic pathway was modestly upregulated during this growth stage, and treatment with BR or its biosynthetic inhibitor brassinazole (BRZ) also promoted or inhibited, respectively, fiber growth. However, the effect of ethylene treatment was much stronger than that of BR, and the inhibitory effect of BRZ on fiber cells could be overcome by ethylene, but the AVG effect was much less reversed by BR. These results indicate that ethylene plays a major role in promoting cotton fiber elongation. Furthermore, ethylene may promote cell elongation by increasing the expression of sucrose synthase, tubulin, and expansin genes.
Shi
Yong-Hui
YH
National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China.
Zhu
Sheng-Wei
SW
Mao
Xi-Zeng
XZ
Feng
Jian-Xun
JX
Qin
Yong-Mei
YM
Zhang
Liang
L
Cheng
Jing
J
Wei
Li-Ping
LP
Wang
Zhi-Yong
ZY
Zhu
Yu-Xian
YX
D000598:Amino Acids, Cyclic / Q000235:genetics / Q000378:metabolism; D049108:Cell Enlargement / Q000187:drug effects; D002473:Cell Wall / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005030:Ethylenes / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D020869:Gene Expression Profiling; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D003368:Gossypium / Q000166:cytology* / Q000235:genetics / Q000254:growth & development*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D014230:Triazoles / Q000494:pharmacology; D015854:Up-Regulation
D000598:Amino Acids, Cyclic; D005030:Ethylenes; D014230:Triazoles; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene; C412342:brassinazole; C088137:aminoethoxyvinylglycine; D005998:Glycine