Conclusion
Plants adapt to unfavorable environmental conditions by dynamic
development at physiological, biochemical, and morphological levels.
These complex responses involve several signaling, metabolites,
transcription factors, and hormones. Our results strengthen the concept
of stress interaction, pointing out as the combined heat and drought
stress is not merely the combination of the single stresses but rather
the result of a multi-level interaction that involves specialized
metabolites and a complex remodelling of phytohormones. Intriguingly,
the metabolomics signatures were shaped in a coordinated manner with
root and rhizosphere bacterial microbiota, suggesting the complete plant
holobiont should be considered when studying the responses of plants to
abiotic stresses. In fact, a complex series of stress sensors and stress
signaling processes is likely orchestrating the responses at plant and
microbiota levels to mediate plant microbiota assembly and promote a
harmonized modulation of stress mitigation processes.