Overexpression of the Arabidopsis 14-3-3 protein GF14λ in cotton leads to a Stay-Green phenotype and improves stress tolerance under moderate drought conditions

The Arabidopsis gene GF14lambda that encodes a 14-3-3 protein was introduced into cotton plants to explore the physiological roles that GF14lambda might play in plants. The expression level of GF14lambda under the control of the cauliflower mosaic virus 35S promoter varied in transgenic cotton plants, and lines that expressed GF14lambda demonstrated a stay-green phenotype and improved water-stress tolerance. These lines wilted less and maintained higher photosynthesis than segregated non-transgenic control plants under water-deficit conditions. Stomatal conductance appears to be the major factor for the observed higher photosynthetic rates under water-deficit conditions. The stomatal aperture of transgenic plants might be regulated by GF14lambda through some transporters such as H+-ATPase whose activities are controlled by their interaction with 14-3-3 proteins. However, since 14-3-3 proteins interact with numerous proteins in plant cells, many metabolic processes could be affected by the GF14lambda overexpression. Whatever the mechanisms, the traits observed in the GF14lambda-expressing cotton plants are beneficial to crops under certain water-deficit conditions.