TOND1, a Novel Gene Improves Tolerance to Nitrogen Deficiency in Rice

Nitrogen (N), the most important mineral nutrient for plants, is critical to agricultural production systems. An N deficiency could severely affect rice growth and decrease rice yields. However, the excessive use of N fertilizer has caused severe pollution to the agricultural and ecological environments. Breeding crops that require less input of N fertilizer has been called for in the ‘Second Green Revolution’. Here, we identified a major quantitative trait locus on chromosome 12, Tolerance Of Nitrogen Deficiency 1 (TOND1), which confers tolerance to N deficiencies in rice of the indica cultivar Teqing. Sequence verification of 150 rice cultivars (75 indica and 75 japonica cultivars) from 18 countries and regions demonstrates that only 27.3% cultivars (41 indica cultivars) contain TOND1 whereas 72.7% cultivars, including the remaining 34 indica cultivars and all 75 japonica cultivars, did not harbor the TOND1 allele. Over-expression of TOND1 has increased the tolerance to N deficiency in the TOND1-deficient rice cultivars. The identification of TOND1 provides a molecular basis for breeding rice varieties that improve grain yield with decreased N fertilizer input.