An aerobic, Gram-stain-negative, rod-shaped, DDT-resistant bacterium, designated strain CC-ALB-2(T), was isolated from the Arabidopsis thaliana rhizosphere. Strain CC-ALB-2(T) was able to grow at 25-37 �XC, at pH 5.0-8.0, with 1.0% (w/v) NaCl and tolerate up to 200 mg l(-1) DDT. 16S rRNA gene sequence analysis of strain CC-ALB-2(T) showed highest sequence similarity to Novosphingobium stygium KCTC 2891(T) (97.1%) and Novosphingobium soli DSM 22821(T) (96.8%), and lower levels of similarity (<97.0%) to other species of the genus Novosphingobium. The major fatty acid profile consisted of C14 : 0 2-OH (13.1%), C16 : 0 (10.0%), C(15 : 0) iso 3-OH (5.8%), C(16: 1)�s7c/C(16 :1)�s6c (summed feature 3, 24.7%) and C(18 : 1)�s7c/C(18 : 1)�s6c (summed feature 8, 42.4%). The polar lipid profile constitutes sphingoglycolipid, glycolipid, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidyldimethylethanolamine, phosphatidylglycerol and phosphatidylcholine. The polyamine pattern showed a predominance of spermidine as the major polyamine. The predominant quinone system was ubiquinone (Q-10). The DNA G+C content was 68.9 �� 0.1 mol%. Based on the phylogenetic, phenotypic and chemotaxonomic features, strain CC-ALB-2(T) is proposed to represent a novel species of the genus Novosphingobium for which the name Novosphingobium arabidopsis sp. nov. is proposed. The type strain is CC-ALB-2(T) (= BCRC 80571(T) = JCM 18896(T)).