Cloning of Lactate dehydrogenase Gene and Effect on the Waterlogging Tolerance of Brassica napus L

To investigate the mechanism on waterlogging tolerance in Brassica napus, 12 B. napus cultivars with different waterlogging tolerance were used in the research and Waterlogging Tolerance Index (WTI) was calculated by multiplying relative percentage germination and the relative seedling height. The results indicated that Lactate Dehydrogenase (LDH) enzyme activity rapidly increased at 24 h after waterlogging treatment and reached peak between 48-72 h. WTI was correlated with LDH enzyme activity at 24 h after water logging treatment and the correlation coefficient between them was 0.84. Transcription level of the BnLDH had significant difference in the 12 lines after waterlogging treatment. BnLDH expression level was very low before waterlogging treatment and induced by waterlogging treatment and arrived at peak at 48 h. Correlation analysis indicated correlation coefficient between WTI and BnLDH expression at 24 and 48 h after waterlogging treatment was 0.56 and 0.72, respectively. An LDH gene, denoted BnLDH-1, was cloned from oilseeds by the Rapid Amplification of CDNA Ends (RACE) from 12 materials and the results indicated all of them had same protein sequence.