EPFL peptide signalling ensures robust self‐pollination success under cool temperature stress by aligning the length of the stamen and pistil

Abstract Successful sexual reproduction of plants requires temperature‐sensitive processes, and temperature stress sometimes causes developmental asynchrony between male and female reproductive tissues. In Arabidopsis thaliana , self‐pollination occurs when the stamen and pistil lengths are aligned in a single flower so that pollens at the stamen tip are delivered to the stigma at the pistil tip. Although intercellular signalling acts in several reproduction steps, how signalling molecules, including secreted peptides, contribute to the synchronous growth of reproductive tissues remains limited. Here, we show that the mutant of the secreted peptide EPIDERMAL PATTERNING FACTOR LIKE 6 ( EPFL6 ), which shows no phenotypes at a moderate temperature, fails in fruit production at a cool temperature due to insufficient elongation of stamens. EPFL6 is expressed in stamen filaments and promotes filament elongation to achieve the alignment of stamen and pistil lengths at a cool temperature. We also found that, at a moderate temperature, all EPFL6 ‐subfamily genes are required for stamen elongation. Furthermore, we showed that ERECTA (ER), known as a common receptor for EPFL‐family peptides, mediates the stamen–pistil growth coordination. Lastly, we provided evidence that modulation of ER activity rescues the reproduction failure caused by insufficient stamen elongation by realigning the stamen and pistil lengths.