胜肽在植物病害保護之研究

Abstract

植物病害為全球嚴重問題，而使用友善環境的病害防治策略十分重要。抗菌胜肽 (antimicrobial peptides，簡稱AMPs) 能透過直接與病原菌作用而抑制病原微生物，而防禦訊息胜肽 (defense signaling peptides，簡稱DSPs) 則是能誘導不同物種自身的免疫機制而達到對抗病原微生物之效果。針對中研院生化所的陳佩燁博士團隊新設計之多種AMPs，我們在多種培養基中以minimal inhibitory concentration (MIC) 與minimal lethal concentration (MLC) 測試所得結果顯示，多種AMPs對許多重要病原細菌與真菌具有抑制效果，而AMPs之帶正電胺基酸含量比例越高與α螺旋結構傾向越低對AMPs抑菌效果越好，並且在特定酸鹼度時之特殊構型跟AMPs抑制微生物效果有關連性。這些AMPs之抑菌效果與其造成病原菌細胞膜損傷相關，而具有脂肪酸鏈修飾可能是它們有效之原因。此外，AMPs之疏水性胺基酸種類不同與脂肪酸修飾之長度不同皆會影響其抑菌效果。其中一些AMPs在番茄、阿拉伯芥及圓葉菸草上具有減緩Botrytis cinerea (Bc) 與 Pectobacterium carotovorum subsp. carotovorum (Pcc) 所引起病害之效。除此之外，我們也發現DSPs 類 AtPep1與AtPep3在番茄與阿拉伯芥上具有減緩Bc與Pcc所引起病害之效，顯示其新功能。這些結果對於AMPs之後續改良提供了重要的可能方向，預期將有助於新穎廣效抗菌胜肽之基礎研究與應用研發。

Plant diseases are important issues worldwide, and thus the development of environmetally friendly means for disease control is certainly important and highly desired. Antimicrobial peptides (AMPs) and defense signaling peptides (DSPs) can benefit plant protection. Through the collaboration with Dr. Rita Pei-Yeh Chen (Institute of Biological Chemistry, Academia Sinica), a group of AMPs were de-novo designed and a group of AMPs showed efficacy on suppressing the growth of a wide range of economically important bacterial and fungal pathogens by determining the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) in various media. High content of positive-charged amino acids and low α–helix structural propensity tend to promote the efficacy, and the formation of this structure under specific pH seems to correlate with the efficacy. In addition, modifications with lipid chains and replacements with hydrophobic amino acids affect the efficacy as well. The AMPs-caused disruption on the microbial cell membrane appears is a key for the antimicrobial activity. The efficacy of a few AMPs and DSPs on lessening diseases caused by Botrytis cinerea (Bc) and Pectobacterium carotovorum subsp. carotovorum (Pcc) was further revealed on tomato and Arabidopsis. These results are projected to benefit the development of peptide-based disease control means.