연사 : 윤대진 교수(경상대학교 생명과학부)
연제 : Cross-talks between the control of flowering time and the response to salinity stress in Arabidopsis
일시 : 2015년 9월 18일 (금) 오후 4시
장소 : 하나과학관 A동 109호
초청교수 : 유상동 교수
Abstract
The Salt Overly Sensitive (SOS)
signaling pathway that in Arabidopsiscomprises the sodium transport protein SOS1, the protein kinase SOS2, and the
calcium-dependent interacting proteins SOS3 and CBL10, has been shown to play a
critical role in cellular signaling under salt stress. The SOS pathway
maintains cellular ion homeostasis by mediating sodium extrusion at the root
and the long distance transport of sodium ions from roots to shoots, thereby
imparting salt tolerance to all plant species that have been genetically
tested. Environmental challenges, including salinity, typically entail
retardation of vegetative growth and delay or cessation of flowering. The
flowering time regulator GIGANTEA (GI) is a key component in the photoperiodic
control pathway of flowering. In Arabidopsis,
GI is predominantly associated with the promotion of flowering in long-day
growth. Recently, our group discovered a molecular link between GI and
adaptation to salt stress that is mechanistically based on GI degradation under
saline conditions, thereby retarding flowering (Kim et al., 2013). GI and the
salt tolerance-related protein kinase SOS2 interact physically. In the absence
of stress, the GI:SOS2 complex prevents SOS2-based activation of SOS1, the
major plant Na/H antiporter mediating adaptation to salinity. GI-overexpressing, rapidly flowering
plants show greater salt sensitivity, whereas gi mutants exhibit delayed flowering and enhanced salt tolerance,
in correspondence with the physical status of SOS2. Salt-induced degradation of
GI confers salt tolerance by the release of the SOS2 kinase. The GI?SOS2
interaction introduces a higher order regulatory circuit that can explain in
molecular terms, the long observed connection between floral transition and
adaptive environmental stress tolerance in Arabidopsis.