Effects of enhancing leaf nitrogen output on tiller growth and carbon metabolism in rice

Abstract

<p id="C3">Nitrogen fertilizer application is one of the main cultivation measures to raise the yield, and high nitrogen level has limited contribution to grain yield due to limited nitrogen translocation in rice. To clarify the effects of nitrogen allocation on rice growth, we constructed<italic> pOsSUT1::AtAMT1.2 </italic>transgenic rice, the ammonium transporter gene <italic>AtAMT1.2</italic> specific expression in phloem to promote leaf nitrogen output. The growth and yield of transgenic plants were measured under HN (high nitrogen) and LN (low nitrogen) conditions. Compared to WT plants, more tillers and higher grain yield were detected in transgenic plants in response to HN condition. The sugar output in leaves was increased, and the relative expression levels of the strigolactone pathway related genes<italic> OsTB1</italic> and <italic>OsD14</italic> in tiller buds were down-regulated. Our results indicated that the increase of leaf nitrogen export by overexpressing <italic>AtAMT1.2</italic> gene could promote sugar translocation from leaves to tillering buds, which improved the growth of tiller, increased the effective tiller number and nitrogen use efficiency.