Trans-Zeatin induce regulation the biosynthesis of 2-acetyl-1-pyrroline in fragrant rice (Oryza sativa L.) seedlings
Pipeng Xing, Haowen Luo, Zhenzhen He, Longxin He, Hua Zhao, Xiangru Tang, Meiyang Duan
Abstract
Abstract Background In plants, cytokinin is activated into trans-zeatin to fight abiotic stresses. However, the mechanism of the effect of trans-zeatin on 2-acetyl-1-pyrroline (2-AP) biosynthesis in fragrant rice has yet to be studied. The present study was conducted to explore the effects of exogenous trans-zeatin on enzymes activities, genes expression, and precursors involved in 2-AP biosynthesis and 2-AP contents as well as the seedling quality of a fragrant rice cultivar viz., Meixiangzhan2. Four concentrations of trans-zeatin solutions at 20, 40, and 80 μmol L − 1 (ZT1, ZT2, and ZT3) were sprayed onto rice seedlings. Results Compared to the control, trans-zeatin treatments showed significantly higher 2-AP contents of fragrant rice seedlings. Increased plant height and stem width were observed due to trans-zeatin treatments. The trans-zeatin application increased 1-pyrroline, methylglyoxal, proline, and P5C contents, enhanced P5CS and OAT activities, and reduced glutamic acid contents. In addition, expressions of ProDH , P5CS2 , and DAO4 were comparatively higher under trans-zeatin treatments than CK in fragrant rice seedlings. Conclusions Overall, up-regulation of P5C, 1-pyrroline, and proline and down-regulation of glutamic acid under appropriate trans-zeatin concentrations (20 and 40 μmol L − 1 ) resulted in enhanced 2-AP biosynthesis in fragrant rice seedlings and 20–40 μmol L − 1 was considered as the suggested concentrations of trans-zeatin application in fragrant rice seedling.