Exploring the miRNA-mediated response to combined stress conditions in
melon plants.
Abstract
Climate change has been associated with a higher incidence of combined
adverse environmental conditions that can promote a significant decrease
in crop productivity. However, knowledge on how a combination of
stresses might affect plant development is still scarce. MicroRNAs
(miRNAs) have been proposed as potential targets for improving
crop-productivity. Here, we have combined deep-sequencing, computational
characterization of responsive miRNAs and validation of their regulatory
role in a comprehensive analysis of melon’s response to several
combinations of four stresses (cold, salinity, short day, and infection
with a fungus). Twenty-two miRNA families responding to double and/or
triple stresses were identified. The regulatory role of the
differentially expressed miRNAs was validated by quantitative
measurements of the expression of the corresponding target genes. A high
proportion (ca. 60%) of these families (mainly highly conserved miRNAs
targeting transcription factors) showed a non-additive response to
multiple stresses in comparison with that observed under each one of the
stresses individually. Among those miRNAs showing non-additive response
to stress-combinations, most interactions were negative suggesting the
existence of functional convergence in the miRNA-mediated response to
combined stresses. Taken together, our results provide compelling
evidences that the response to combined stresses cannot be easily
predicted from the study individual stresses.