Israeli Scientists Discover Seed Salt Tolerance Mechanism

Researchers at the Hebrew University of Jerusalem have identified how seeds maintain mineral balance in saline soil, enabling successful germination. Soil salinization, a global challenge exacerbated by irrigation, renders vast agricultural lands unusable due to salt accumulation. Understanding plants' molecular responses to salt stress could allow for the reclamation of moderately saline fields.

Excess salt hinders water absorption and disrupts the mineral balance crucial for growth. Through studies on the model plant Arabidopsis thaliana, scientists observed how seeds retain essential potassium while blocking toxic sodium. This balance is facilitated by calcium acting through three proteins: CAMTA6, PP2C49, and HKT1;1. CAMTA6, responsive to calcium signals, regulates the other genes, with the plant tailoring its salt defense to specific organs like cotyledons and roots for precise control.

The findings, published in The Plant Journal, shed light on the critical germination stage. "Germination is an extremely vulnerable stage in a plant's life. Salt can disrupt the mineral balance needed by a young plant even before it germinates," stated co-author Dr. Doron Shkolnik. "What we are beginning to uncover is the control system behind this plant response to salt."

Biologists demonstrated that sanguinarine, a natural plant alkaloid, aids seed germination under salinity. With sanguinarine, seed germination rates increased from 76% to 92% under moderate salt stress and from 3% to 37% under high salinity, though its effect is limited to germination. This identified molecular system is part of a larger genetic network, with future research aiming to uncover additional genes that can help crops thrive on saline soils, ultimately aiding farmers in combating soil salinization and restoring land for agriculture.