High-throughput micro-plate HCI-vanillin assay for screening tannin content in sorghum grain.

Background: The HCI-vanillin assay is a well-accepted method for determining tannin content in sorghum but is limited to small sample sets due to the time-consuming nature of the method. The objective was to develop an accurate and repeatable high-throughput 96-well plate assay for breeders to screen large sample sets of sorghum for tannin content. Validation of the high-throughput assay was tested on 25 sorghums suspected to contain tannin.

Results: Approximately 30 measurements per day were completed using the conventional assay compared to 224 measurements using the 96-well platform. The correlation between the two tannin assays was 0.98. The coefficient of variation (CV) was 3.54% and 3.21% for the 96-well and conventional method, respectively. The 96-well assay exhibited good repeatability, with the inter-plate CV between 2.77% and 4.85%.

Conclusion: The high-throughput 96-well HCI-vanillin assay exhibited an eightfold increase in the number of measurements completed and was as accurate as the conventional HCI-vanillin assay.