Transgenic soybeans expressing betaine aldehyde dehydrogenase from Atriplex canescens show increased drought tolerance

Betaine aldehyde dehydrogenase (BADH) catalyses the oxidation of betaine aldehyde to glycine betaine. To test whether BADH can increase drought tolerance in soybean (Glycine max), BADH from the drought‐tolerant plant Atriplex canescens (AcBADH) was introduced into the soybean cultivar ‘Jinong 17’ by Agrobacterium‐mediated cotyledon transformation. Eight independent AcBADH transgenic lines were subjected to drought stress. As expected, AcBADH was expressed in transgenic soybean leaves and not in the control. In transgenic plants, AcBADH expression increased following drought treatment. Under osmotic stress, the germination index was 6%–17% higher in the transgenic lines than in the control. Using a randomized block design, we measured drought‐related physiological indices and yield traits. The proline content in AcBADH transgenic soybeans increased by 12.5%–16.6%, peroxidase activity increased by 1%–7%, dry weight of plant increased by 15%–20% and malondialdehyde contents decreased by 1.5%–13%, compared to the control. Under drought conditions, two of the eight transgenic soybean lines had higher yields than the control, with increases of 7.59%–8.84%. Therefore, transgenic expression of AcBADH may provide a promising strategy to engineer drought tolerance without adverse consequences.