Submitted to: Plant Biology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/7/2007
Publication Date: 7/11/2007
Citation: Chen, J., Xin, Z., Burke, J.J. 2007. FtsH11 Proteases play a critical role in high temperature stress tolerance in plants [abstract]. Plant Biology and Botany 2007 Joint Congress, July 7-11, 2007, Chicago, Illinois. CD-ROM
Technical Abstract: FtsHs (Filamentous temperature sensitive H), ATP-dependent zinc metalloproteases of the AAA-superfamily, play essential roles in the turn over of thylakoid proteins damaged by high light stress during photosynthesis. Here, we show that FtsH11, one of the 12 FtsH members in Arabidopsis, plays critical roles in the thermostability of photosynthetic systems as well as in the early stages of chloroplast biogenesis. Using positional cloning, we identified a thermosentive locus, atts405, as AtFtsH11. Subsequently, we demonstrated the mutations within this gene, including knockout mutation by T-DNA insertion, rendered mutant plants sensitive to mild thermal stress (30°C) and impeded the ability to acquire thermotolerance. Prolonged exposure at or above 30°C resulted in cessation of plant growth and development, and eventually death. However, all the ftsh11 mutants displayed normal response to high light stresses. Photosynthetic capabilities were greatly reduced in ftsh11 mutants after an exposure to 30oC but not to high light, which set FtsH11 apart from all other characterized Arabidopsis FtsH proteases. The loss of thermotolerance in ftsh11 mutants is not associated with expression of major heat shock proteins. Furthermore, we demonstrated that overexpression of a pea ortholog, PsFtsH11, in Arabidopsis ftsh11 mutants could complement the thermosentive phenotype. Our results provide the first direct evidence that FtsH11 protease plays an essential role in plant thermotolerance.