Poster: Abiotic Stress
Abs #
P10067: The role of Hsa32 in basal thermotolerance in Arabidopsis
|
|
Presenter: |
Wu, Szu-hsien Contact Presenter |
Authors | Wu, Szu-hsien (A) Chi, Wen-tzu (A) Charng, Yee-yung (A) | | Affiliations: |
(A): Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
|
|
|
Hsa32 is a novel heat-shock-induced protein mainly found in land plants. Arabidopsis T-DNA knockout (KO) mutant of Hsa32 has severe defect in acquired thermotolerance after long but not short recovery following an acclimation treatment. Here, we show that AtHsa32 is also required for basal thermotolerance (BT). The Hsa32 KO plants died after a short and severe heat shock (HS) challenge while the wild type remained alive. Since the level of Hsa32 protein in the wild-type seedlings was not detectable by western blot under normal condition or during the heat shock treatment, it raised a question regarding the action mode of Hsa32 on BT. Western blot analysis showed that Hsa32, as well as Hsp101 and sHsp-CI, was dramatically induced one day after the severe HS, suggesting that the post-HS induction of Hsa32 as well as other Hsps is essential if not sufficient for BT. Interestingly, disruption of Hsa32 dramatically retarded the post-HS induction of other Hsps, suggesting that Hsa32 plays a role in regulating post-HS response. Similar situation was observed in the Hsp101 KO line, which suggests a complex interplay between Hsa32 and Hsp101 in BT. Consistenly, inhibiting the synthesis of Hsps by actinomycin D or cycloheximide during recovery diminished the BT level of the wild-type plants. In addition, we show that HsfA1a/1b was required for BT based on the survival rate assay. Suppression of post-HS induction of Hsps was also observed in the double KO mutant of the transcription factor genes, suggesting that HsfA1a/1b play an important role in transcription regulation of the post-HS response. Taken together, we conclude that basal thermotolerance requires the timely induction of Hsp genes during recovery which are under the control of HsfA1a/b.
