PAG1, a cotton brassinosteroid catabolism gene, modulates fiber elongation.
Cotton (Gossypium hirsutum) is the major source of natural textile fibers. Brassinosteroids (BRs) play crucial roles in regulating fiber development. The molecular mechanisms of BRs in regulating fiber elongation, however, are poorly understood. pagoda1 (pag1) was identified via an activation tagging genetic screen and characterized by genome walking and brassinolide (BL) supplementation. RNA-Seq analysis was employed to elucidate the mechanisms of PAG1 in regulating fiber development. pag1 exhibited dwarfism and reduced fiber length due to significant inhibition of cell elongation and expansion. BL treatment rescued its growth and fiber elongation. PAG1 encodes a homolog of Arabidopsis CYP734A1 that inactivates BRs via C-26 hydroxylation. RNA-Seq analyses showed that the constitutive expression of PAG1 downregulated the expression of genes involved in very-long-chain fatty acids (VLCFA) biosynthesis, ethylene-mediated signaling, response to cadmium, cell wall development, cytoskeleton organization and cell growth. Our results demonstrate that PAG1 plays crucial roles in regulating fiber development via controlling the level of endogenous bioactive BRs, which may affect ethylene signaling cascade by mediating VLCFA. Therefore, BR may be a critical regulator of fiber elongation, a role which may in turn be linked to effects on VLCFA biosynthesis, ethylene and cadmium signaling, cell wall- and cytoskeleton-related gene expression.
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Zuoren
Z
Yang
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Chaojun
C
Zhang
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Xiaojie
X
Yang
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Kun
K
Liu
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Zhixia
Z
Wu
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Xueyan
X
Zhang
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Wu
W
Zheng
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Qingqing
Q
Xun
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Chuanliang
C
Liu
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Lili
L
Lu
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Zhaoen
Z
Yang
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Yuyuan
Y
Qian
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Zhenzhen
Z
Xu
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Changfeng
C
Li
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences, Lanzhou University, Lanzhou, 730000, China.
Jia
J
Li
State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, 455000, China.
Fuguang
F
Li
D017360:Arabidopsis / Q000235:genetics; D060406:Brassinosteroids / Q000378:metabolism / Q000494:pharmacology; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D005030:Ethylenes / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D003368:Gossypium / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D009154:Mutation; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D015398:Signal Transduction / Q000235:genetics; D013260:Steroids, Heterocyclic / Q000378:metabolism / Q000494:pharmacology
D060406:Brassinosteroids; D005030:Ethylenes; D010940:Plant Proteins; D013260:Steroids, Heterocyclic; D003577:Cytochrome P-450 Enzyme System; C036216:ethylene; C023623:brassinolide
activation tagging; brassinosteroid (BR); cotton (Gossypium hirsutum); fiber elongation; transcriptome