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Rice shaker potassium channel OsAKT2 positively regulates salt tolerance and grain yield by mediating K + redistribution
Author(s) -
Tian Quanxiang,
Shen Like,
Luan Junxia,
Zhou Zhenzhen,
Guo Dongshu,
Shen Yue,
Jing Wen,
Zhang Baolong,
Zhang Qun,
Zhang Wenhua
Publication year - 2021
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.14101
Subject(s) - phloem , shoot , potassium , chromosomal translocation , mutant , chemistry , redistribution (election) , homeostasis , biophysics , sodium , salt (chemistry) , botany , biology , microbiology and biotechnology , biochemistry , gene , organic chemistry , politics , political science , law
Maintaining Na + /K + homeostasis is a critical feature for plant survival under salt stress, which depends on the operation of Na + and K + transporters. Although some K + transporters mediating root K + uptake have been reported to be essential to the maintenance of Na + /K + homeostasis, the effect of K + long‐distance translocation via phloem on plant salt tolerance remains unclear. Here, we provide physiological and genetic evidence of the involvement of phloem‐localized OsAKT2 in rice salt tolerance. OsAKT2 is a K + channel permeable to K + but not to Na + . Under salt stress, a T‐DNA knock‐out mutant, osakt2 and two CRISPR lines showed a more sensitive phenotype and higher Na + accumulation than wild type. They also contained more K + in shoots but less K + in roots, showing higher Na + /K + ratios. Disruption of OsAKT2 decreases K + concentration in phloem sap and inhibits shoot‐to‐root redistribution of K + . In addition, OsAKT2 also regulates the translocation of K + and sucrose from old leaves to young leaves, and affects grain shape and yield. These results indicate that OsAKT2‐mediated K + redistribution from shoots to roots contributes to maintenance of Na + /K + homeostasis and inhibition of root Na + uptake, providing novel insights into the roles of K + transporters in plant salt tolerance.