Nitrogen fertilizers, such as nitrate (NO3-) or ammonium (NH4 +), improve grain yield, but the use of great amounts of nitrogen leads to water and air pollution. The main cereals (such as rice and wheat) utilize only about 40% of the applied fertilizer – the rest is lost to the air, water and soil microbes. The production of nitrogen fertilizers also uses fossil fuels. In many cases, nitrogen fertilizers slow down flowering, leaving the cultivars vulnerable to cold weather at the end of the season. A recent study on rice (Oryza sativa) identified a nitrate transporter (NRT), which can provide a solution to the problem of nitrogen utilization and delayed flowering. A study by Wang et al., published in The Plant Cell, shows that the rice gene OsNRT1.1A can affect both nitrogen use and flowering time. Mutant lines lacking this transporter show reduced utilization of nitrate and ammonium. To improve yield and time of flowering, the authors developed rice lines that produce extra OsNRT1.1A. Plants overexpressing OsNRT1.1A become higher, greener and produce more biomass than regular rice grown on the same amount of nitrogen. These plants also utilize more nitrate and ammonium from the environment in experiments conducted in hydroponic conditions. The manipulation of the expression of OsNRT1.1A has the potential to increase yields and accelerate flowering, two of the most important traits desired in the breeding of many plant species.
Source: SeedQuest
