Overexpression of the Novel Arabidopsis GeneAt5g02890Alters Inflorescence Stem Wax Composition and Affects Phytohormone Homeostasis.
The cuticle is composed of cutin and cuticular wax. It covers the surfaces of land plants and protects them against environmental damage.At5g02890encodes a novel protein inArabidopsis thaliana. In the current study, protein sequence analysis showed that At5g02890 is highly conserved in theBrassicaceae. Arabidopsis lines overexpressingAt5g02890(OE-At5g02890 lines) and anAt5g02890orthologous gene fromBrassica napus(OE-Bn1 lines) exhibited glossy stems. Chemical analysis revealed that overexpression ofAt5g02890caused significant reductions in the levels of wax components longer than 28 carbons (C28) in inflorescence stems, whereas the levels of wax molecules of chain length C28 or shorter were significantly increased. Transcriptome analysis indicated that nine of 11 cuticular wax synthesis-related genes with different expression levels in OE-At5g02890 plants are involved in very-long-chain fatty acid (VLCFA) elongation. At5g02890 is localized to the endoplasmic reticulum (ER), which is consistent with its function in cuticular wax biosynthesis. These results demonstrate that the overexpression ofAt5g02890alters cuticular wax composition by partially blocking VLCFA elongation of C28 and higher. In addition, detailed analysis of differentially expressed genes associated with plant hormones and endogenous phytohormone levels in wild-type and OE-At5g02890 plants indicated that abscisic acid (ABA), jasmonic acid (JA), and jasmonoyl-isoleucine (JA-Ile) biosynthesis, as well as polar auxin transport, were also affected by overexpression ofAt5g02890. Taken together, these findings indicate that overexpression ofAt5g02890affects both cuticular wax biosynthesis and phytohormone homeostasis in Arabidopsis.
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Liping
L
Xu
Institute of Cellular and Molecular Botany, University of Bonn Bonn, Germany.
Viktoria
V
Zeisler
Institute of Cellular and Molecular Botany, University of Bonn Bonn, Germany.
Lukas
L
Schreiber
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Jie
J
Gao
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Kaining
K
Hu
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Jing
J
Wen
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Bin
B
Yi
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Jinxiong
J
Shen
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Chaozhi
C
Ma
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Jinxing
J
Tu
National Key Laboratory of Crop Genetic Improvement, National Center of Rapeseed Improvement, Huazhong Agricultural University Wuhan, China.
Tingdong
T
Fu
Arabidopsis thaliana; At5g02890; Brassica napus; VLCFAs; cuticular wax; phytohormones