In response to environmental challenges, plant cells activate several signaling pathways that trigger the expression of transcription factors. Arabidopsis MYB60 was reported to be involved in stomatal regulation under drought conditions. Here, two splice variants of the MYB60 gene are shown to play a crucial role in stomatal movement. This role was demonstrated by over-expressing each variant, resulting in enhanced sensitivity to water deficit stress. The MYB60 splice variants, despite the fact that one of which lacks the first two exons encoding the first MYB DNA binding domain, both localize to the nucleus and promote guard cell deflation in response to water deficit. Moreover, MYB60 expression is increased in response to a low level of ABA and decreased in response to high level of ABA. At initial stage of drought stress, the plant system may modulate the root growth behavior by regulating MYB60 expression, thus promotes root growth for increased water uptake. In contrast, severe drought stress inhibits the expression of the MYB60 gene, resulting in stomatal closure and root growth inhibition. Taken together, these data indicate that MYB60 plays a dual role in abiotic stress responses in Arabidopsis through its involvement in stomatal regulation and root growth.
Bibliographical noteFunding Information:
Acknowledgments This work was supported by a grant from the Korea Research Foundation to Hojoung Lee (2009; Grant #2011-0003726) in part by a grant from the Korea Research Foundation to Suk-Whan Hong (grant #2011-0003259 and #2011-0018393). The authors express their gratitude to Dr. Cominelli for providing seeds of the myb60 knock-out line.
- Arabidopsis thaliana
- Drought stress
- Guard cell
ASJC Scopus subject areas
- Agronomy and Crop Science
- Plant Science