Increasing temperatures brought about by climate changenegatively affect
crop productivity. To deal with the heat, plants use hormones to grow
larger, developing a bigger surface area they can use to cool down.
However, it has been unclear which hormones do plants use in this
mechanism, and scientists at VIB-UGent Center for Plant Systems Biology
are finding an answer to that question.

The plant hormone jasmonic acid plays an important role in various
stress responses, including wound response, cold, and heat stress. Does
it also play a role in the heat-induced growth of plants? Prof. Ive De
Smet's team, including Ph.D. student Tingting Zhu, first author of the
study, says: "Our starting point was previously published data on the
proteins affected in wheat seedlings exposed to high temperatures. To
explore if jasmonate signaling indeed plays a role in the growth in
response to warmer temperatures, we used both Arabidopsis and wheat as
model plants."

By investigating the gene expression in Arabidopsis seedlings under
different temperature conditions, the researchers find that this leads
to an increased expression of the genes JOXs and ST2a. These
genescontrol the breakdown of jasmonic acid, which normally stops
growth. As the temperature rises, so does the activity of these two
genes. In turn, this lowers the level of jasmonic acid, and lower
jasmonic acid means more growth. The scientists analyzed the growth
ofwheatunder warm temperatures and found the same mechanism at work.

VIB - How plants grow more to deal with heat
[vib.be]