diff --git a/2025.4/amplicon/passed/seed-environment-conda.yml b/2025.4/amplicon/passed/seed-environment-conda.yml
index 3d1e7954..f2e98c0e 100644
--- a/2025.4/amplicon/passed/seed-environment-conda.yml
+++ b/2025.4/amplicon/passed/seed-environment-conda.yml
@@ -53,6 +53,7 @@ dependencies:
 - sepp=4.5.5
 - unifrac-binaries=1.4
 - unifrac=1.3
+- rpy2=3.5.11
 extras:
   variant_override:
     qiime2_epoch: '2025.4'