Phenotypic analysis of RNAiUBL5b in root elongation and development.

(A) Growth of RNAiUBL5b#1, RNAiUBL5b#2, and WT. Plants were grown for 7 days. Bar = 5 mm. (B) Root lengths of RNAiUBL5b#1 and RNAiUBL5b#2 plants. (C) Relative expression levels of AtUBL5a and AtUBL5b in RNAiUBL5b#1 and RNAiUBL5b#2 plants were estimated by quantitative real time polymerase chain reaction (qRT-PCR) and compared to that of WT plants. The expression level of each gene was normalized to that of ACTIN 2 (ACT2). (D) Auxin sensitivity of RNAiUBL5b#1. RNAiUBL5b#1 and control WT seedlings were cultivated for 5 days, then transferred to MS media containing different concentrations of 2,4-D (auxin). Bar = 10 mm. (E) The sensitivity of RNAiUBL5b#1 and WT to auxin was assessed by measuring root elongation defects and the number of lateral roots. Values in (B), (C), and (E) represent mean ± standard deviations of 8–10 samples of three independent experiments. Asterisks in (B), (C), and (E) indicate statistical significance according to Student’s t test ***P < 0.000 1, **P < 0.001.