A fasciclin-like arabinogalactan protein, GhFLA1, is involved in fiber initiation and elongation of cotton.
Arabinogalactan proteins (AGPs) are involved in many aspects of plant development. In this study, biochemical and genetic approaches demonstrated that AGPs are abundant in developing fibers and may be involved in fiber initiation and elongation. To further investigate the role of AGPs during fiber development, a fasciclin-like arabinogalactan protein gene (GhFLA1) was identified in cotton (Gossypium hirsutum). Overexpression of GhFLA1 in cotton promoted fiber elongation, leading to an increase in fiber length. In contrast, suppression of GhFLA1 expression in cotton slowed down fiber initiation and elongation. As a result, the mature fibers of the transgenic plants were significantly shorter than those of the wild type. In addition, expression levels of GhFLAs and the genes related to primary cell wall biosynthesis were remarkably enhanced in the GhFLA1 overexpression transgenic fibers, whereas the transcripts of these genes were dramatically reduced in the fibers of GhFLA1 RNA interference plants. An immunostaining assay indicated that both AGP composition and primary cell wall composition were changed in the transgenic fibers. The levels of glucose, arabinose, and galactose were also altered in the primary cell wall of the transgenic fibers compared with those of the wild type. Together, our results suggested that GhFLA1 may function in fiber initiation and elongation by affecting AGP composition and the integrity of the primary cell wall matrix.
Hubei Key Laboratory of Genetic Regulation and Integrative Biology, College of Life Sciences, Central China Normal University, Wuhan 430079, People's Republic of China.
Geng-Qing
GQ
Huang
Si-Ying
SY
Gong
Wen-Liang
WL
Xu
Wen
W
Li
Peng
P
Li
Chao-Jun
CJ
Zhang
Deng-Di
DD
Li
Yong
Y
Zheng
Fu-Guang
FG
Li
Xue-Bao
XB
Li
D015153:Blotting, Western; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D032561:Cotton Fiber; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D005960:Glucosides / Q000494:pharmacology; D003368:Gossypium / Q000166:cytology / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D015151:Immunoblotting; D007150:Immunohistochemistry; D009088:Mucoproteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D018517:Plant Roots / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D030821:Plants, Genetically Modified; D011134:Polysaccharides / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism
D005960:Glucosides; D009088:Mucoproteins; D010940:Plant Proteins; D011134:Polysaccharides; C104977:Yariv reagent; C006619:arabinogalactan proteins; D010696:Phloroglucinol