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Hydrogen peroxide mediates abscisic acid‐induced HSP 70 accumulation and heat tolerance in grafted cucumber plants
Author(s) -
LI HAO,
LIU SHANSHAN,
YI CHANGYU,
WANG FENG,
ZHOU JIE,
XIA XIAOJIAN,
SHI KAI,
ZHOU YANHONG,
YU JINGQUAN
Publication year - 2014
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.12360
Subject(s) - abscisic acid , hydrogen peroxide , chemistry , microbiology and biotechnology , biochemistry , biology , gene
Root–shoot communications play important roles in plant stress responses. Here, we examined the roles of root‐sourced signals in the shoot response to heat in cucumber plants. Cucumber plants grafted onto their own roots and luffa roots were exposed to aerial and root‐zone heat to examine their tolerance by assessing the levels of oxidative stress, PSII photoinhibition, accumulation of abscisic acid ( ABA ), H 2 O 2 and heat shock protein ( HSP ) 70 using immunoblotting, chlorophyll fluorescence, immunoassay, CeCl 3 staining and Western blotting, respectively. Grafting onto the luffa rootstock enhanced the shoot tolerance to the heat. This enhanced tolerance was associated with increased accumulation of ABA and apoplastic H 2 O 2 , RBOH transcripts and HSP 70 expression and a decrease in oxidative stress in the shoots. The increases in the ABA and H 2 O 2 concentrations in the shoots were attributed to an increase in ABA transport from roots and an increase in ABA biosynthesis in the shoots when the root‐zone and shoots were heat stressed, respectively. Inhibition of H 2 O 2 accumulation compromised luffa rootstock‐induced HSP 70 expression and heat tolerance. These results suggest that, under heat stress, ABA triggers the expression of HSP 70 in an apoplastic H 2 O 2 ‐dependent manner, implicating the role of an ABA ‐dependent H 2 O 2 ‐driven mechanism in a systemic response involving root–shoot communication.