Memory Genes Allow Maize to Adapt to Repeated Dehydration Stress

Stress memory is the plants' ability to alter their physiological and transcriptional responses to stresses when pre-exposed to a wide array of abiotic stresses. In Arabidopsis thaliana, plants that have experienced exposures to dehydration exhibit transcriptional behavior that suggests the plants' memory of the earlier stress. Some genes respond to the first stress by changing their transcription but provide a different response to following stresses. These are the 'memory genes'. However, it is still unknown whether these memory responses exist in other angiosperms.

The transcriptional responses of maize (Zea mays L.) plants with repeated exposures to drought stress were compared with the responses of plants exposed to the stress for the first time. Four separate transcription memory response patterns similar to those displayed by A. thaliana were discovered. There is also evidence that monocot and eudicot plants display similar abilities to 'remember' a dehydration stress. Transcription patterns indicate that the behavior of responding genes to repeated stresses is different from the behavior during the initial stress, suggesting that stress memory is a complex phenotype resulting from coordinated responses of multiple-signaling pathways.

These results provide new insights into the knowledge of plants response to multiple dehydration stresses compared to a single exposure. It may serve as a reference for studies on memory genes.

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