Cloning and characterization of the Gossypium hirsutum major latex protein gene and functional analysis in Arabidopsis thaliana.
The major latex protein (MLP) gene in Gossypium hirsutum was cloned and designated Gh-MLP. Expression in cotton root was induced by salt stress and Verticillium dahliae toxin, and bioinformatic analysis showed that Gh-MLP encodes a 157-amino acid protein that is similar to members of the MLP subfamily in the Bet v 1 family. Although the structure of MLP is similar to Bet v 1 family proteins, the sequence identity to other subfamilies of Bet v 1 proteins is less than 20%. The Gh-MLP promoter contains potential cis-acting elements for response to salt stress and fungal elicitor. RT-PCR analysis showed that Gh-MLP expression was rapidly induced by NaCl and V. dahliae toxin, and induction was maintained over 72 h. However, Gh-MLP transgenic Arabidopsis thaliana did not show resistance to V. dahiae, salt tolerance was significantly enhanced. In contrast to the wild type, the Gh-MLP transgene allowed plants to germinate normally after treatment with 75 mM NaCl. Total flavonoid was twofold higher in transgenic Arabidopsis than in the control, suggesting that Gh-MLP might be involved in altering flavonoid content. We hypothesize Gh-MLP, like other Bet v 1 family proteins, participates in the binding or transport of ligands through its specific three-dimensional structure, and takes part in defensive responses to biotic and abiotic stresses.
Chen
Jie-Yin
JY
Institute of Crop Science, Chinese Academy of Agricultural Sciences, 100081 Beijing, People's Republic of China.
Dai
Xiao-Feng
XF
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D019295:Computational Biology; D005419:Flavonoids / Q000378:metabolism; D003368:Gossypium / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D017433:Protein Structure, Secondary; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000494:pharmacology
D005419:Flavonoids; D010940:Plant Proteins; D012965:Sodium Chloride