添加胜肽對毛狀根生物鹼含量之影響

Abstract

愈來愈多的植物胜肽分子被發現會參與植物防禦，藉由啟動茉莉酸訊息傳遞路徑，促進次級代謝物生產。然而這些胜肽在毛狀根累積次級代謝物中扮演怎樣的角色仍所知甚少。本研究中我們首先建立番茄毛狀根。接著利用菸草毛狀根作為研究材料，測試多種胜肽對尼古丁含量之影響，並參考菸草毛狀根之操作程序測並測試胜肽對番茄毛狀根累積番茄鹼能力之影響。研究結果顯示，在菸草毛狀根中，0.1 μM茉莉酸甲酯能刺激尼古丁累積，但添加菸草或番茄系統素後，原本0.1 μM茉莉酸甲酯所能累積之番茄鹼含量受到顯著抑制。而在番茄毛狀根中，同時添加0.1 μM茉莉酸甲酯及番茄系統素或flg22，番茄鹼含量相較只有0.1 μM茉莉酸甲酯的處理下降20%。本研究結果顯示，無論在煙草或是番茄毛狀根中，特定胜肽會抑制0.1 μM茉莉酸甲酯累積代謝物之能力，暗示著與0.1 μM 茉莉酸甲酯及特定胜肽間存在著拮抗關係。

More and more signaling peptides have been discovered to participate in plant defense through stimulating jasmonate (JA) signaling pathway that activates defense genes and enhances the production of secondary metabolites. However, little is known pertaining to the role of peptides in hairy root cultures accumulating secondary metabolites. In this study, tomato hairy roots were first established. Afterwards, tobacco hairy roots were used as the study model to screen out peptides that could affect nicotine content. Based on the screening procedure established in tobacco hairy roots, a screening procedure for the tomato hairy root targeting its metabolite, tomatine, was subsequently developed. Through this process, we found nicotine content elevated by 0.1 µM MeJA but decreased significantly after the addition of tobacco or tomato systemin. Tomatine content decreased by 20% in comparison with that in 0.1 µM MeJA after the addition of tomato systemin or flg22. These results demonstrate that in both tobacco and tomato hairy root cultures, the addition of specific peptides gave rise to a negative effect of 0.1 µM MeJA on accumulating secondary metabolites, suggesting an antagonistic effect between 0.1 µM MeJA and peptides.