diff --git a/docs/dev/datasource-prometheus.md b/docs/dev/datasource-prometheus.md
index 8b07e4dc58b..047da8b5689 100644
--- a/docs/dev/datasource-prometheus.md
+++ b/docs/dev/datasource-prometheus.md
@@ -175,7 +175,7 @@ Since we don't have column names similar to relational databases, `@timestamp` a
 
 ### Passthrough PromQL Support.
 * PromQL is easy to use powerful language over metrics and we want to support promQL queries from catalogs with prometheus connectors.
-* Function signature: source = ``promcatalog.nativeQuery(`promQLCommand`, startTime = "{{startTime}}", endTime="{{endTime}", step="{{resolution}}")``
+* Function signature: source = ``promcatalog.nativeQuery(`promQLCommand`, startTime = "{{startTime}}", endTime="{{endTime}}", step="{{resolution}}")``