Saturated very-long-chain fatty acids promote cotton fiber and Arabidopsis cell elongation by activating ethylene biosynthesis.
Fatty acids are essential for membrane biosynthesis in all organisms and serve as signaling molecules in many animals. Here, we found that saturated very-long-chain fatty acids (VLCFAs; C20:0 to C30:0) exogenously applied in ovule culture medium significantly promoted cotton (Gossypium hirsutum) fiber cell elongation, whereas acetochlor (2-chloro-N-[ethoxymethyl]-N-[2-ethyl-6-methyl-phenyl]-acetamide; ACE), which inhibits VLCFA biosynthesis, abolished fiber growth. This inhibition was overcome by lignoceric acid (C24:0). Elongating fibers contained significantly higher amounts of VLCFAs than those of wild-type or fuzzless-lintless mutant ovules. Ethylene nullified inhibition by ACE, whereas C24:0 was inactive in the presence of the ethylene biosynthesis inhibitor (l-[2-aminoethoxyvinyl]-glycine), indicating that VLCFAs may act upstream of ethylene. C24:0 induced a rapid and significant increase in ACO (for 1-aminocyclopropane-1-carboxylic acid oxidase) transcript levels that resulted in substantial ethylene production. C24:0 also promoted Ser palmitoyltransferase expression at a later stage, resulting in increased sphingolipid biosynthesis. Application of C24:0 not only stimulated Arabidopsis thaliana root cell growth but also complemented the cut1 phenotype. Transgenic expression of Gh KCS13/CER6, encoding the cotton 3-ketoacyl-CoA synthase, in the cut1 background produced similar results. Promotion of Arabidopsis stem elongation was accompanied by increased ACO transcript levels. Thus, VLCFAs may be involved in maximizing the extensibility of cotton fibers and multiple Arabidopsis cell types, possibly by activating ethylene biosynthesis.
Qin
Yong-Mei
YM
National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China.
Hu
Chun-Yang
CY
Pang
Yu
Y
Kastaniotis
Alexander J
AJ
Hiltunen
J Kalervo
JK
Zhu
Yu-Xian
YX
D000081:Acetamides / Q000494:pharmacology; D000217:Acyltransferases / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000378:metabolism; D032561:Cotton Fiber; D005030:Ethylenes / Q000096:biosynthesis*; D005227:Fatty Acids / Q000494:pharmacology*; D035264:Flowers / Q000166:cytology / Q000187:drug effects / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005816:Genetic Complementation Test; D003368:Gossypium / Q000166:cytology* / Q000187:drug effects* / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D012441:Saccharomyces cerevisiae; D013107:Sphingolipids / Q000096:biosynthesis
D000081:Acetamides; D029681:Arabidopsis Proteins; D005030:Ethylenes; D005227:Fatty Acids; D013107:Sphingolipids; C036216:ethylene; D000217:Acyltransferases; C120018:CUT1 protein, Arabidopsis