AUTHOR=Xu Juanjuan , Du Ni , Dong Tianci , Zhang Han , Xue Tao , Zhao Fei , Zhao Fenglan , Duan Yongbo , Xue Jianping 

TITLE=A novel Pinellia ternata catalase gene PtCAT2 regulates drought tolerance in Arabidopsis by modulating ROS balance

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1206798

DOI=10.3389/fpls.2023.1206798

ISSN=1664-462X

ABSTRACT=<p>Drought is one of the major abiotic stresses limiting agricultural production, particularly for shallow-rooted plants like <italic>Pinellia ternata</italic>. It damages plants via oxidative burst, but this effect could be mitigated by catalase (CAT). However, no studies have been reported on CAT homologs in <italic>P. ternata</italic>, a drought-sensitive plant species. In the present study, a novel CAT gene, <italic>PtCAT2</italic>, was functionally characterized via overexpression in <italic>Arabidopsis</italic> and analysis of cis-elements in its promoter. The isolated CAT gene was 1479 bp and encoded a protein containing 242 amino acids. The protein contains the CAT activity motif and the heme-binding site of a typical CAT, and the subcellular analysis indicated that the protein localizes at the cytoplasm and membrane. Moreover, the quantitative real-time reverse transcription PCR indicated that <italic>PtCAT2</italic> is expressed ubiquitously in <italic>P. ternata</italic> and is strongly induced by drought stress and abscisic acid (ABA) signals. <italic>PtCAT2</italic> overexpression enhanced the drought tolerance of <italic>Arabidopsis</italic>, as shown by the 30% increase in plant survival and a five-fold- increase in CAT activity. Moreover, <italic>PtCAT2</italic>-transgenic plants increased superoxide dismutase and peroxidase activities and reduced malondialdehyde, membrane leakage, and hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) (<italic>P</italic>&lt;0.05). Furthermore, <italic>PtCAT2</italic>-transgenic plants showed higher tolerance to oxidative stress caused by exogenous H<sub>2</sub>O<sub>2</sub> and retained higher chlorophyll and water contents than the WT. The mitochondria function was better maintained as presented by the higher oxygen consumption rate in transgenics under drought stress (<italic>P</italic>&lt;0.05). The endogenous <italic>CATs</italic> and drought response-related genes were also upregulated in transgenic lines under drought stress, indicating that <italic>PtCAT2</italic> confers drought stress tolerance by enhancing the H<sub>2</sub>O<sub>2</sub> scavenging ability of plants to maintain their membrane integrity. These results improve our understanding of the drought response mechanisms and provide a potential breeding strategy for <italic>P. ternata</italic> genetic improvement.</p>