The MdOST1-MdCNGC1C-MdCaM7.1 module fine-tunes cold-induced calcium signaling in apple.
Qiu L, Yang J, Qi Z, Zhang W, Liu H
Plant Signaling
Understanding exactly how apple trees sense and survive freezing could help breeders develop frost-resistant varieties, protecting the apple harvests that stock grocery stores and orchards worldwide — especially as unpredictable late frosts become more common with climate change.
When apple trees get hit by cold, their cells rapidly flood with calcium — think of it as a biological alarm bell. Scientists found three proteins that work as a team to control this alarm: one protein turns the calcium flood on when temperatures drop, another shuts it off, and they physically compete to grab the same spot on the 'door' that lets calcium in. The clever part is that the calcium itself tips the balance — once enough pours in, it helps the off-switch win, automatically stopping the signal before it causes damage.
Key Findings
MdCNGC1C, a calcium channel, is activated by the kinase MdOST1 via phosphorylation at a specific site (Serine-47), directly enhancing calcium influx and freezing tolerance in apple.
The calcium sensor protein MdCaM7.1 competes with MdOST1 for binding to the same region (N-terminus) of MdCNGC1C, and when it wins, it inhibits calcium entry and reduces cold tolerance.
Elevated cytoplasmic calcium concentrations promote MdCaM7.1 binding and suppress MdOST1 activity, revealing a calcium-dependent negative feedback loop that self-limits cold-induced calcium signaling.
chevron_right Technical Summary
Scientists discovered a three-protein molecular switch in apple trees that controls how cells flood with calcium during cold stress — a key early alarm signal that helps the plant survive freezing. The system is self-regulating: it turns on when temperatures drop and automatically dials back once calcium levels get too high.
Abstract Preview
Cold stress limits the entire growth cycle of plants, affecting crop yield, quality, and geographic distribution. The calcium ion (Ca2+) signal, generated by rapid and dynamic changes in cytoplasmi...
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An apple is the round, edible fruit of an apple tree. Fruit trees of the orchard or domestic apple, the most widely grown in the genus, are cultivated worldwide. The tree originated in Central Asia, where its wild ancestor, Malus sieversii, is still found. Apples have been grown for thousands of ...