Inhibition of gibberellin accumulation by water deficiency promotes fast and long‐term ‘drought avoidance’ responses in tomato

What is it about?

Plants protect themselves from dehydration by rapid stomatal closure and inhibition of growth, both reducing water loss. These responses, termed ‘drought avoidance’, are regulated primarily by the stress hormone abscisic acid (ABA). Here we show in tomato, that drought-induced reduction in the growth promoting hormone gibberellin (GA) also contributes to drought avoidance. Water deficiency induced GA deactivation in guard cells. Mutants with reduced GA deactivation exhibited delayed stomatal closure in response to soil dehydration and as a result, faster wilting. Drought also inhibited GA synthesis in leaves, leading to growth suppression and restriction of transpiration area. Together, drought-inhibition of GA accumulation promotes rapid physiological and long-term developmental responses that reduce transpiration and improve adaptation to water deficiency.

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