Carnivorous Nutrition in Pitcher Plants (Nepenthes spp.) via an Unusual Complement of Endogenous Enzymes

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• 作者：Linda Lee ; Ye Zhang ; Brittany Ozar ; Christoph W. Sensen ; David C. Schriemer
• 刊名：Journal of Proteome Research
• 出版年：2016
• 出版时间：September 2, 2016
• 年：2016
• 卷：15
• 期：9
• 页码：3108-3117
• 全文大小：559K
• 年卷期：0
• ISSN：1535-3907

文摘

Plants belonging to the genus Nepenthes are carnivorous, using specialized pitfall traps called “pitchers” that attract, capture, and digest insects as a primary source of nutrients. We have used RNA sequencing to generate a cDNA library from the Nepenthes pitchers and applied it to mass spectrometry-based identification of the enzymes secreted into the pitcher fluid using a nonspecific digestion strategy superior to trypsin in this application. This first complete catalog of the pitcher fluid subproteome includes enzymes across a variety of functional classes. The most abundant proteins present in the secreted fluid are proteases, nucleases, peroxidases, chitinases, a phosphatase, and a glucanase. Nitrogen recovery involves a particularly rich complement of proteases. In addition to the two expected aspartic proteases, we discovered three novel nepenthensins, two prolyl endopeptidases that we name neprosins, and a putative serine carboxypeptidase. Additional proteins identified are relevant to pathogen-defense and secretion mechanisms. The full complement of acid-stable enzymes discovered in this study suggests that carnivory in the genus Nepenthes can be sustained by plant-based mechanisms alone and does not absolutely require bacterial symbiosis.