Functional Characterization of Pectin Methylesterase Inhibitor (PMEI) in Wheat

다국어 초록 (Multilingual Abstract)

Pectin, one of the main components of plant cell wall, is deesterified by the pectin methylesterase (PME). PME activity is particularly regulated by inhibitor proteins known as the pectin methylesterase inhibitor (PMEI). The PMEI plays a key role in wounding, osmotic stress, senescence and seed development. However, the role of PMEI in 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. Transcription of the TaPMEI gene was significantly induced in response to each of NaCl, H₂O₂ and SA (salicylic acid) treatment and reduced when plants were treated with ABA (abscisic acid). To elucidate the subcellular localization of the TaPMEI protein, 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 might role in plant defense mechanism via cell wall fortification.

목차 (Table of Contents)

• Introduction = 1
• Materials and methods = 4
• Results = 11
• Discussion = 28
• References = 33