<div>Through crosstalk, FLAGELLIN SENSITIVE 2 (FLS2) and RESPIRATORY BURST
OXIDASE HOMOLOG D (RBOHD) are involved in regulating the homeostasis of
cellular reactive oxygen species (ROS) and are linked to the metabolic
response of plants towards both biotic and abiotic stress. In the
present study, we examined the metabolome of <i>Arabidopsis</i>
seedlings under drought and salt conditions to better understand the
potential role of FLS2 and RBOHD-dependent signaling in the regulation
of abiotic stress response. We identified common metabolites and genes
that are regulated by FLS2 and RBOHD, and are involved in the response
to drought and salt stress. Under drought conditions, D-aspartic acid
(DAA) and the expression of associated genes, such as <i>ASPARAGINE
SYNTHASE 2</i> ( <i>ASN2</i>), increased in both <i>fls2</i> and
<i>robed/f</i> double mutants. The accumulation of amino acids,
carbohydrates, and hormones, such as L-proline, D-ribose, and
indoleacetaldehyde increased in both <i>fls2</i> and <i>rbohd/f</i>
double mutants under salt conditions, as did the expression of related
genes, such as <i>PROLINE IMINOPEPTIDASE</i> ( <i>PIP</i>),
<i>PHOSPHORIBOSYL PYROPHOSPHATE SYNTHASE 5</i> ( <i>PRS5</i>), and
<i>NITRILASE 3</i> ( <i>NIT3</i>). Collectively, these results indicate
that the FLS2-RBOHD module regulates plant response to drought and salt
stress through ROS signaling by adjusting the accumulation of
metabolites and expression of genes related to metabolite synthesis.</div>