Loss of Arabidopsis Halotolerance 2-like (AHL), a 3′-phosphoadenosine-5′-phosphate phosphatase, suppresses insensitive response of Arabidopsis thaliana ring zinc finger 1 (atrzf1) mutant to abiotic stress
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Destruction of PAP phosphatase AHL suppresses atrzf1 phenotype in abiotic stress responses. AHL plays an intermediate role in the regulation of proline accumulation by PAP nucleotidase.
Proline (Pro) metabolism is important for environmental responses, plant development, and growth. However, the role of Pro in abiotic stress process is unclear. Using atrzf1 (Arabidopsis thaliana ring zinc finger 1) mutant as a parental line for T-DNA tagging mutagenesis, we identified a suppressor mutant designated as proline content alterative 17 (pca17) that suppressed insensitivity of atrzf1 to abiotic stresses during early seedling growth. Pro content of pca17 was lower than that in both wild type (WT) and atrzf1 while complementary lines were less sensitive to abscisic acid (ABA) and abiotic stresses compared to WT. Thermal Asymmetric Interlaced (TAIL)-PCR of pca17 showed that T-DNA was inserted at site of At5g54390 (AHL for Arabidopsis Halotolerance 2-like) encoding 3′-phosphoadenosine-5′-phosphate (PAP) phosphatase. Under drought stress condition, products of sulfate metabolism such as PAP and adenosine monophosphate were significantly lower in pca17 than those in WT and atrzf1. Furthermore, pca17 showed significantly higher levels of several important drought parameters including malondialdehyde, ion leakage, and water loss than WT and atrzf1. Fluorescence signal of green fluorescent protein (GFP)-tagged AHL was quite strong in nuclei of the root and guard cells of transgenic seedlings. Additionally, AHL promoter-β-glucuronidase (GUS) construct revealed substantial gene expression in vasculature tissues and pollen. Collectively, these findings demonstrate that pca17 acts as a dominant suppressor mutant of atrzf1 in abiotic stress response by modulating proline and sulfate metabolism.
KeywordsAbiotic stress response Adenosine monophosphate AtRZF1 PAP pathway pca mutant Proline
Green fluorescent protein
Quantitative real-time polymerase chain reaction
This work was supported in part by a grant to C.S.K. from the Next-Generation BioGreen21 program (SSAC, PJ013171) funded by the Rural Development Administration and by the Basic Science Research Program funded by the Ministry of Education, Science and Technology of Korea (2018R1D1A1B07045242).
We thank Dr. Y-MK for technical assistance with HPLC analysis. CSK designed experiments and interpreted results. DJS, JHM, and TVN carried out experiments and interpreted the results.
Compliance with ethical standards
Conflict of interest
The authors have no conflicts of interest relevant to this study to disclose.
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