Biotech Updates

Potassium Transport Gene in Soybean Enhances Its Resistance to Soybean Mosaic Virus

June 11, 2014

Potassium is the most abundant inorganic solute in plant cells and is involved in plant responses to abiotic and biotic stresses. Previous studies have shown that altering the level of potassium can reduce the spread of viral diseases. Thus, potassium transporters are leading targets for breeding for virus resistance, including  soybean mosaic virus (SMV), the most prevalent viral disease in soybean.

Addition of potassium fertilizer was found to significantly reduce SMV incidence. Upon analysis, the gene GmAKT2 was significantly induced by SMV inoculation in resistant varieties but not in susceptible varieties. Transgenic soybean overexpressing GmAKT2 were also generated and evaluated. Significant increase in potassium concentrations was observed in young leaves of the transgenic soybean. Meanwhile, potassium concentrations in the old leaves of the transgenic plants were lower than in wildtype plants. These indicate that GmAKT2 acted as a potassium transporter and affected the distribution of potassium in soybean plants.

Wildtype plants exhibited severe mosaic symptoms while transgenic plants showed no symptoms of SMV, suggesting that virus development was significantly retarded in the transgenic soybean plants. Overexpression of GmAKT2 enhanced SMV resistance in soybean. Hence, manipulation of potassium transporter expression is a novel molecular approach for enhancing SMV resistance.

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