Abstract:

‘YY021’ is a hybrid tobacco variety selected for dryland tobacco growing areas. In order to identify the drought tolerance of ‘YY021’, ‘Zhongyan 100’ was used as the control variety, and the drought-rehydration experiment of floating seedling was arranged to investigate wilting index and water content, observe the changes of active oxygen, and measure the content of malonaldehyde, proline and the expression of drought-related gene by qRT-PCR. The results showed that with the prolongation of drought time, the leaf water content of ‘Zhongyan 100’ and ‘YY021’ decreased and the wilting index increased. The content of malonaldehyde increased with the extension of drought time. The expression of osmotin gene decreased first and then increased from 0-7 d of drought. After 7 days of drought, compared with ‘Zhongyan 100’, the leaf moisture content of‘YY021’ increased by 4.31%, the wilting index of ‘YY021’ decreased by 3.97%, and the contents of malondialdehyde decreased by 9.21%, and the contents of proline increased by 84.71%. Compared with ‘Zhongyan 100’, ‘YY021’ had lower levels of reactive oxygen species and malondialdehyde, and the higher osmotin gene expression. The ERD gene responded more rapidly. The drought tolerance of ‘YY021’ was better than that of ‘Zhongyan 100’. Under drought stress, the damage of reactive oxygen species to membrane of ‘YY021’ was reduced by accumulating osmotic adjustment substance proline. ERD and osmotin genes may be candidate genes for drought tolerance of ‘YY021’.

Key words: flue-cured tobacco, ‘YY021’, drought tolerance, drought-rehydration, water content, MDA, proline, gene expression