AUTHOR=Yue Jie-yu , Wang Ying-jie , Jiao Jin-lan , Wang Wen-wen , Wang Hua-zhong 

TITLE=The Metacaspase TaMCA-Id Negatively Regulates Salt-Induced Programmed Cell Death and Functionally Links With Autophagy in Wheat

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.904933

DOI=10.3389/fpls.2022.904933

ISSN=1664-462X

ABSTRACT=<p>Metacaspases (MCAs), a family of caspase-like proteins, are important regulators of programmed cell death (PCD) in plant defense response. Autophagy is an important regulator of PCD. This study explored the underlying mechanism of the interaction among PCD, MCAs, and autophagy and their impact on wheat response to salt stress. In this study, the wheat salt-responsive gene <italic>TaMCA-Id</italic> was identified. The open reading frame (ORF) of <italic>TaMCA-Id</italic> was 1,071 bp, coding 356 amino acids. The predicted molecular weight and isoelectric point were 38,337.03 Da and 8.45, respectively. <italic>TaMCA-Id</italic> had classic characteristics of type I MCAs domains, a typical N-terminal pro-domain rich in proline. <italic>TaMCA-Id</italic> was mainly localized in the chloroplast and exhibited nucleocytoplasmictrafficking under NaCl treatment. Increased expression of <italic>TaMCA-Id</italic> in wheat seedling roots and leaves was triggered by 150 mM NaCl treatment. Silencing of <italic>TaMCA-Id</italic> enhanced sensitivity of wheat seedlings to NaCl stress. Under NaCl stress, <italic>TaMCA-Id</italic>-silenced seedlings exhibited a reduction in activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), higher accumulation of H<sub>2</sub>O<sub>2</sub> and <inline-formula><mml:math id="M1" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mtext>O</mml:mtext><mml:mn>2</mml:mn><mml:mrow><mml:mo>.</mml:mo><mml:mo>−</mml:mo></mml:mrow></mml:msubsup></mml:mrow></mml:math></inline-formula>, more serious injury to photosystem II (PSII), increase in PCD level, and autophagy activity in leaves of wheat seedlings. These results indicated that <italic>TaMCA-Id</italic> functioned in PCD through interacting with autophagy under NaCl stress, which could be used to improve the salt tolerance of crop plants.</p>