Carnivorous plants from the order Caryophyllales co-opted plant phytohormones from a group of jasmonates to regulate digestive enzyme activity. However, not all genera of carnivorous plants have been thoroughly explored, and the digestive physiology of Australian carnivorous rainbow plants of the genus Byblis (order Lamiales) is poorly understood. Here, we investigated the composition of digestive enzymes in the secreted fluid of Byblis filifolia using LC/MS, measured enzyme activity, and analysed tissue phytohormone levels after experimental feeding with fruit flies and coronatine application. Several hydrolytic digestive enzymes were identified in the secreted digestive fluid, the levels of which clearly increased in the presence of insect prey. However, in contrast to the sundew Drosera capensis, endogenous jasmonates do not accumulate, and coronatine, a molecular mimic of jasmonates, is unable to trigger enzyme secretion. Our results showed that B. filifolia is fully carnivorous, with its own digestive enzyme repertoire. However, in contrast to carnivorous genera from the Caryophyllales order, these enzymes are not regulated by jasmonates. This indicates that jasmonates have not been repeatedly co-opted to regulate digestive enzyme activity during the evolution of carnivorous plants.

• Keywords
• Byblis, Carnivorous plant, Drosera, digestive enzyme, jasmonic acid, phytohormones, sundew,
• MeSH
• Amino Acids metabolism   pharmacology   MeSH
• Caryophyllales * enzymology   physiology   metabolism   MeSH
• Cyclopentanes * metabolism   MeSH
• Drosera physiology   MeSH
• Indenes metabolism   pharmacology   MeSH
• Carnivorous Plant * enzymology   physiology   metabolism   MeSH
• Oxylipins * metabolism   MeSH
• Plant Growth Regulators * metabolism   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Amino Acids MeSH
• coronatine MeSH Browser
• Cyclopentanes * MeSH
• Indenes MeSH
• jasmonic acid MeSH Browser
• Oxylipins * MeSH
• Plant Growth Regulators * MeSH

The carnivorous plants in the order Caryophyllales co-opted jasmonate signalling from plant defence to botanical carnivory. However, carnivorous plants have at least 11 independent origins, and here we ask whether jasmonate signalling has been co-opted repeatedly in different evolutionary lineages. We experimentally wounded and fed the carnivorous plants Sarracenia purpurea (order Ericales), Cephalotus follicularis (order Oxalidales), Drosophyllum lusitanicum (order Caryophyllales), and measured electrical signals, phytohormone tissue level, and digestive enzymes activity. Coronatine was added exogenously to confirm the role of jasmonates in the induction of digestive process. Immunodetection of aspartic protease and proteomic analysis of digestive fluid was also performed. We found that prey capture induced accumulation of endogenous jasmonates only in D. lusitanicum, in accordance with increased enzyme activity after insect prey or coronatine application. In C. follicularis, the enzyme activity was constitutive while in S. purpurea was regulated by multiple factors. Several classes of digestive enzymes were identified in the digestive fluid of D. lusitanicum. Although carnivorous plants from different evolutionary lineages use the same digestive enzymes, the mechanism of their regulation differs. All investigated genera use jasmonates for their ancient role, defence, but jasmonate signalling has been co-opted for botanical carnivory only in some of them.

• Keywords
• Aspartic protease, carnivorous plant, digestive enzymes, electrical signal, jasmonic acid, phytohormone, plant defence, wounding,
• MeSH
• Carnivory * MeSH
• Carnivorous Plant * MeSH
• Proteomics MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• coronatine MeSH Browser
• jasmonic acid MeSH Browser