The MADS-box genes PaMADS3/4/5 co-regulate multi-pistil formation induced by high temperature in Prunus avium L.

Multi-pistil is a significant physiological disorder that decreases sweet cherry commercial value. Here, we found multi-pistil formation occurred more frequently in the warm region of Shanghai than that in the cool region of Dalian. Previous studies have shown that the MADS-box genes play an important role in regulating pistil development. To characterize the regulatory mechanisms of MADS-box genes underlying multi-pistil formation in sweet cherries, three reported MADS-box genes-PaMADS3/4/5, were cloned in sweet cherry cv 'Van', and identified belonging to class E and class C to regulate carpels. Interestingly, the qRT-PCR expression analysis showed PaMADS3/4/5 was sensitive to high temperature. Moreover, our findings showed PaMADS3 was a heat-inducible transcription factor, and corroborated the interactions between class C-(PaMADS5) and E-(PaMADS3 and PaMADS4) proteins. Collectively, heat induces expression of PaMADS3, and PaMADS3-PaMADS5, PaMADS5-PaMADS4 protein complexes contribute to the multi-pistil formation in sweet cherries.