Polyamines and ethylene interact in mediating the effect of nitrogen rates on synthesis of amino acids in rice grains

It is not clear yet about the mechanism underlying how different N rates influence the amino acid contents in rice grains. Our study showed grain free-polyamines and ethylene antagonistically interact in mediating the effect of N rate on grain amino acid biosynthesis of rice. A higher ratio of free-polyamines to 1-aminocylopropane-1-carboxylic acid (a synthesis precursor of ethylene) is beneficial to the synthesis of amino acids in rice grains. AbstractNitrogen (N) is one of the essential factors influencing amino acid synthesis in rice (Oryza sativa L.) grains. Polyamines (PAs) and ethylene (ETH) play vital roles in grain amino acid biosynthesis of rice. However, knowledge is limited about whether and how PAs and ETH mediate the effect of N rate on amino acid biosynthesis. Two rice cultivars were used with three N rates of low (LN), medium (MN), and high (HN) in the study. Levels of free PAs and ETH, activities/gene expressions of key enzymes related to amino acid synthesis in grains, and the amino acid contents in milled rice were investigated. Free spermidine (Spd) and spermine (Spm) concentrations, especially ratios of free PAs to 1-aminocylopropane-1-carboxylic acid (ACC), and total amino acids (TAAs), essential amino acids (EAAs), and non-essential amino acids (NEAAs) contents were increased with N rate, while ethylene evolution rate (EER) and ACC concentration were reduced with N increases. There was relatively little difference in the above parameters between MN and H...

Source: Food and Energy Security - July 19, 2022 Category: Food Science Authors: Yunji Xu, Shupeng Tang, Chaoqun Jian, Yang Liu, Ke Li, Kuanyu Zhu, Weiyang Zhang, Weilu Wang, Zhiqin Wang, Jianchang Yang Tags: ORIGINAL ARTICLE Source Type: research