Background
High temperature is a major environmental stress that limits plant growth and agriculture productivity. Mitogen-activated protein kinases (MAPKs) are highly conserved serine and threonine protein kinases that participate in response to diverse environmental stresses in plants. A total of 16 putative
SlMAPK
genes are identified in tomato, and
SlMAPK3
is one of the most extensively studied
SlMAPKs
. However, the role of
SlMAPK3
in response to heat stress is not clearly understood in tomato plants. In this study, we performed functional analysis of
SlMAPK3
for its possible role in response to heat stress.
Results
qRT-PCR analyses revealed that
SlMAPK3
relative expression was depressed by heat stress. Here, wild-type (WT) tomato plants and CRISPR/Cas9-mediated
slmapk3
mutant lines (L8 and L13) were used to investigate the function of
SlMAPK3
in response to heat stress. Compared with WT plants,
slmapk3
mutants exhibited less severe wilting and less membrane damage, showed lower reactive oxygen species (ROS) contents, and presented higher both activities and transcript levels of antioxidant enzymes, as well as elevated expressions of genes encoding heat stress transcription factors (
HSFs
) and heat shock proteins (
HSPs
).
Conclusions
CRISPR/Cas9-mediated
slmapk3
mutants exhibited more tolerance to heat stress than WT plants, suggesting that
SlMAPK3
was a negative regulator of thermotolerance. Moreover, antioxidant enzymes and
HSPs
/
HSFs
genes expression were involved in
SlMAPK3
-mediated heat stress response in tomato plants.
Electronic supplementary material
The online version of this article (10.1186/s12870-019-1939-z) contains supplementary material, which is available to authorized users.