Functional characterization of pectin methylesterase inhibitor (PMEI) in wheat.
Pectin, one of the main components of plant cell wall, is deesterified by the pectin methylesterase (PME). PME activity is regulated by inhibitor proteins known as the pectin methylesterase inhibitor (PMEI), which plays a key role in wounding, osmotic stress, senescence and seed development. However, the role of PMEI in many plant species still remains to be elucidated, especially in wheat. To facilitate the expression analysis of the TaPMEI gene, RT-PCR was performed using leaf, stem and root tissues that were treated with exogeneous application of phytohormones and abiotic stresses. High transcription was detected in salicylic acid (SA) and hydrogen peroxide treatments. To elucidate the subcellular localization of the TaPMEI protein, the TaPMEI:GFP fusion construct was transformed into onion epidermal cells by particle bombardment. The fluorescence signal was exclusively detected in the cell wall. Using an enzyme assay, we confirmed that PME was completely inhibited by TaPMEI. These results indicated that TaPMEI was involved in inhibition of pectin methylesterification and may play a role in the plant defense mechanism via cell wall fortification.
Hong
Min Jeong
MJ
College of Life Sciences and Biotechnology, Korea University.
Kim
Dae Yeon
DY
Lee
Tong Geon
TG
Jeon
Woong Bae
WB
Seo
Yong Weon
YW
D000595:Amino Acid Sequence; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000037:antagonists & inhibitors*; D002473:Cell Wall / Q000201:enzymology; D003001:Cloning, Molecular; D017931:DNA Primers; D004791:Enzyme Inhibitors / Q000737:chemistry*; D018506:Gene Expression Regulation, Plant; D007700:Kinetics; D008969:Molecular Sequence Data; D010368:Pectins / Q000378:metabolism*; D018515:Plant Leaves / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics; D018547:Plant Stems / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014908:Triticum / Q000235:genetics* / Q000378:metabolism
D017931:DNA Primers; D004791:Enzyme Inhibitors; D010940:Plant Proteins; D018749:RNA, Plant; D011994:Recombinant Proteins; D010368:Pectins; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase