Arabidopsis ABI5 plays a role in regulating ROS homeostasis by activating CATALASE 1 transcription in seed germination

Abstract

It has been known that ABA INSENSITIVE 5 (ABI5) plays a vital role in regulating seed germination. In the present study, we showed that inhibition of the catalase activity with 3-amino-1,2,4-triazole (3-AT) inhibits seed germination of Col-0, abi5 mutants and ABI5-overexpression transgenic lines. Compared with Col-0, the seeds of abi5 mutants showed more sensitive to 3-AT during seed germination, while the seeds of ABI5-overexpression transgenic lines showed more insensitive. H2O2 showed the same effect on seed germination of Col-0, abi5 mutants and ABI5-overexpression transgenic lines as 3-AT. These results suggest that ROS is involved in the seed germination mediated by ABI5. Further, we observed that T-DNA insertion mutants of the three catalase members in Arabidopsis displayed 3-AT-insensitive or -hypersensitive phenotypes during seed germination, suggesting that these catalase members regulate ROS homeostasis in a highly complex way. ABI5 affects reactive oxygen species (ROS) homeostasis by affecting CATALASE expression and catalase activity. Furthermore, we showed that ABI5 directly binds to the CAT1 promoter and activates CAT1 expression. Genetic evidence supports the idea that CAT1 functions downstream of ABI5 in ROS signaling during seed germination. RNA-sequencing analysis indicates that the transcription of the genes involved in ROS metabolic process or genes responsive to ROS stress is impaired in abi5-1 seeds. Additionally, expression changes in some genes correlative to seed germination were showed due to the change in ABI5 expression under 3-AT treatment. Together, all the findings suggest that ABI5 regulates seed germination at least partly by affecting ROS homeostasis.Electronic supplementary materialThe online version of this article (doi:10.1007/s11103-017-0603-y) contains supplementary material, which is available to authorized users.

Reactive oxygen species in plant development

“…By contrast, mitochondrial thioredoxin O1 (trxo1) mutants exhibit accelerated germination together with increased H₂O₂ levels (Ortiz-Espín et al, 2017). It was also recently shown that, in Arabidopsis thaliana, the transcription factor ABI5 regulates H 2 O 2 homeostasis in addition to its core role in ABAdependent signaling; specifically, ABI5 assists the germination process by binding to the promoter of the CATALASE 1 gene and regulating its expression and hence H 2 O 2 levels (Skubacz et al, 2016;Bi et al, 2017).…”

Heterologous Expression of a Soybean Gene RR34 Conferred Improved Drought Resistance of Transgenic Arabidopsis

“…ABI5 is a basic leucine zipper TF, playing key roles in abiotic stress response through regulating gene expression of various downstream targets [88], whereas, RAB18 is a functional protein (i.e., dehydrin), which is responsible for cellular protection under water deficit conditions [87,89]. Furthermore, a previous study demonstrated that CAT1 could be the downstream gene regulated by ABI5 [90], whereby their expression upon drought treatment were both up-regulated ( Figures 3D and 5D). Taken these results with lower water loss rates (importantly within the first h of dehydration) observed in the transgenic Arabidopsis together, it is suggested that GmRR34 enhances drought resistance of the transgenic plants in an ABA-dependent manner, at least by promoting the closure of stomata under water-deficit condition.…”

Description of a Zostera marina catalase gene involved in responses to temperature stress

“…The expression profile of CAT was a key part of the plant defense system against oxidative stress ( Bi et al, 2017 ). In the present study, Zm CAT appeared to be regulated at the transcriptional level for detoxifying increased H 2 O 2 during cold stress conditions.…”