Plant Genomics and Plant Science

Plants have evolved complex molecular, cellular and physiological mechanisms to respond to environmental stressors. Although genetic manipulation has not been largely successful, it represents an important method for improving water deficit tolerance in agricultural crops. Aldehyde dehydrogenases involved in cellular responses to oxidative/electrophilic stress protect against a variety of environmental stressors. In the past, we cloned and characterized moss-unique ALDH21 homologue from Syntrichia caninervis (ScALDH21), an extremely desiccation-tolerant moss found in deserts of Central Asia.  ScALDH21 gene plays important roles in plant responses to abiotic stresses, as overexpression of this gene in tobacco and cotton decreases the sensitivity of these plants to drought and salt stresses, suggesting that the ScALDH21 gene plays a critical role in abiotic stress responses. To test the possibility that transgenic ScALDH21 cotton may be suitable for cultivating under water deficit conditions, the phenotype, physiological response and yield of transgenic ScALDH21 cotton were measured in drought pool and field experiments. We report here that overexpression of ScALDH21 in cotton results in higher net photosynthesis, less cell damage, more cell protective substances and better growth than wild-type cotton under drought stress in drought pool. As compared with none transgenic control, yield of transgenic cotton lines under reduced irrigation condition increased more than yield under normal irrigation conditions. Seed cotton yield in the field increased approximately 10.0% under normal irrigation conditions and increased approximately 21.0% under deficit irrigation conditions compared with control. Furthermore, fiber quality character in transgenic cotton lines increased than that of control under normal and deficit irrigation conditions. These results suggest that transgenic ScALDH21 cotton is a viable candidate material to improve crop yields in water-limited agricultural production systems.