diff --git a/jcvi/graphics/base.py b/jcvi/graphics/base.py
index 6e594f66..f1ed271c 100644
--- a/jcvi/graphics/base.py
+++ b/jcvi/graphics/base.py
@@ -3,10 +3,11 @@
 
 import copy
 import os.path as op
-from os import remove
-
+import re
 import sys
 
+from os import remove
+
 from functools import partial
 from typing import Optional, List, Tuple, Union
 
@@ -408,11 +409,14 @@ def fontprop(ax, name, size=12):
     return prop
 
 
-def markup(s):
+def markup(s: str):
+    """
+    Change the string to latex format, and italicize the text between *.
+    """
+    if not rcParams["text.usetex"]:
+        return s
     if "$" in s:
         return s
-    import re
-
     s = latex(s)
     s = re.sub(r"\*(.*)\*", r"\\textit{\1}", s)
     return s
diff --git a/tests/graphics/test_base.py b/tests/graphics/test_base.py
index 88066444..0477bd90 100644
--- a/tests/graphics/test_base.py
+++ b/tests/graphics/test_base.py
@@ -3,6 +3,8 @@
 
 import pytest
 
+from jcvi.graphics.base import latex, markup, rc
+
 
 @pytest.mark.parametrize(
     "s,expected",
@@ -24,15 +26,21 @@ def test_shorten(s, expected):
 @pytest.mark.parametrize(
     "s,expected",
     [
-        ("grape_grape vs peach_peach", "grape\_grape vs peach\_peach"),
+        ("grape_grape vs peach_peach", r"grape\_grape vs peach\_peach"),
     ],
 )
 def test_latex(s, expected):
-    from jcvi.graphics.base import latex
-
     assert latex(s) == expected, "Expect {}".format(expected)
 
 
+def test_markup():
+    rc("text", usetex=True)
+    s = "Prupe_1G289800.1"
+    assert markup(s) == r"Prupe\_1G289800.1"
+    rc("text", usetex=False)
+    assert markup(s) == s
+
+
 @pytest.mark.parametrize(
     "figname,format,expected",
     [