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Melatonin improves rice salinity stress tolerance by NADPH oxidase‐dependent control of the plasma membrane K + transporters and K + homeostasis
Author(s) -
Liu Juan,
Shabala Sergey,
Zhang Jing,
Ma Guohui,
Chen Dandan,
Shabala Lana,
Zeng Fanrong,
Chen ZhongHua,
Zhou Meixue,
Venkataraman Gayatri,
Zhao Quanzhi
Publication year - 2020
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.13759
Subject(s) - melatonin , nadph oxidase , chemistry , transporter , efflux , biochemistry , microbiology and biotechnology , biophysics , biology , oxidative stress , endocrinology , gene
This study aimed to reveal the mechanistic basis of the melatonin‐mediated amelioration of salinity stress in plants. Electrophysiological experiments revealed that melatonin decreased salt‐induced K + efflux (a critical determinant of plant salt tolerance) in a dose‐ and time‐dependent manner and reduced sensitivity of the plasma membrane K + ‐permeable channels to hydroxyl radicals. These beneficial effects of melatonin were abolished by NADPH oxidase blocker DPI. Transcriptome analyses revealed that melatonin induced 585 (448 up‐ and 137 down‐regulated) and 59 (54 up‐ and 5 down‐regulated) differentially expressed genes (DEGs) in the root tip and mature zone, respectively. The most noticeable changes in the root tip were melatonin‐induced increase in the expression of several DEGs encoding respiratory burst NADPH oxidases ( OsRBOHA and OsRBOHF ), calcineurin B‐like/calcineurin B‐like‐interacting protein kinase ( OsCBL / OsCIPK ), and calcium‐dependent protein kinase ( OsCDPK ) under salt stress. Melatonin also enhanced the expression of potassium transporter genes ( OsAKT1 , OsHAK1 , and OsHAK5 ). Taken together, these results indicate that melatonin improves salt tolerance in rice by enabling K + retention in roots, and that the latter process is conferred by melatonin scavenging of hydroxyl radicals and a concurrent OsRBOHF ‐dependent ROS signalling required to activate stress‐responsive genes and increase the expression of K + uptake transporters in the root tip.