Influence of Host Nectar in Sarracenia purpurea on its Microbiome
Mentor 1
Erica Young
Start Date
28-4-2023 12:00 AM
Description
The carnivorous pitcher plant Sarracenia purpurea secretes extrafloral nectar to attract insect prey which may fall into modified leaf pitchers. Rainwater collects and a diverse microbiome grows inside the pitcher. Microbial communities secrete hydrolytic enzymes critical for host plant nutrient acquisition from degraded insects. In new pitchers, before insect capture, resources are scarce for microbes. Our hypothesis is that nectar may wash in with rainfall, supporting bacterial growth. However, whether this happens, and effect on microbes is unknown. Nectar samples were collected from 50 pitcher plants located at the Cedarburg Bog using cotton swabs dipped in sterile water. The pitchers were swabbed separately on the inside and outside of the pitcher lip roll to determine possibility for washing into the pitcher. Microplate assays were developed to determine nectar sugar and amino acid content. Anthrone colorimetric assay quantified carbohydrate content and compared with sucrose standards. Total free amino acid concentration was determined with OPAME fluorometric assays, compared with leucine standards. Nectar concentrations were similar on the inside and outside of the pitcher lip suggesting rain could wash nectar sugars and amino acids into the pitcher community. To test the effect of this, an artificial nectar was formulated with sucrose, leucine, methionine, valine, and glutamate based on measured content of S. purpurea nectar. Water collected from field pitchers was filtered and artificial nectar was added. Bacterial growth was examined as changes in optical density. After 7 days, there was significantly more growth in higher nectar addition treatments, but none in the controls. The nectar addition effect saturated at ~100 μL suggesting very little nectar can contribute to early bacterial growth in pitcher plant communities. Nectar sugars and amino acid subsidies could be a mechanism for the host plant to support microbiome growth critical for carnivorous nutrient acquisition in S. purpurea.
Influence of Host Nectar in Sarracenia purpurea on its Microbiome
The carnivorous pitcher plant Sarracenia purpurea secretes extrafloral nectar to attract insect prey which may fall into modified leaf pitchers. Rainwater collects and a diverse microbiome grows inside the pitcher. Microbial communities secrete hydrolytic enzymes critical for host plant nutrient acquisition from degraded insects. In new pitchers, before insect capture, resources are scarce for microbes. Our hypothesis is that nectar may wash in with rainfall, supporting bacterial growth. However, whether this happens, and effect on microbes is unknown. Nectar samples were collected from 50 pitcher plants located at the Cedarburg Bog using cotton swabs dipped in sterile water. The pitchers were swabbed separately on the inside and outside of the pitcher lip roll to determine possibility for washing into the pitcher. Microplate assays were developed to determine nectar sugar and amino acid content. Anthrone colorimetric assay quantified carbohydrate content and compared with sucrose standards. Total free amino acid concentration was determined with OPAME fluorometric assays, compared with leucine standards. Nectar concentrations were similar on the inside and outside of the pitcher lip suggesting rain could wash nectar sugars and amino acids into the pitcher community. To test the effect of this, an artificial nectar was formulated with sucrose, leucine, methionine, valine, and glutamate based on measured content of S. purpurea nectar. Water collected from field pitchers was filtered and artificial nectar was added. Bacterial growth was examined as changes in optical density. After 7 days, there was significantly more growth in higher nectar addition treatments, but none in the controls. The nectar addition effect saturated at ~100 μL suggesting very little nectar can contribute to early bacterial growth in pitcher plant communities. Nectar sugars and amino acid subsidies could be a mechanism for the host plant to support microbiome growth critical for carnivorous nutrient acquisition in S. purpurea.
