Xiaoli Shi, Fa Cui, Xinyin Han, Yilin He, Long Zhao, Na Zhang, Haidong Zhu, Zhexin Liu, Bin Ma, Shusong Zheng, Wei Zhang, Jiajia Liu, Xiaoli Fan, Yaoqi Si, Shuiquan Tian, Jianqing Niu, Huilan Wu, Xuemei Liu, Zhuo Chen, Deyuan Meng, Hao Zhang, Xiaoyan Wang, Liqiang Song, Lijing Sun, Jie Han, Hui Zhao, Jun Ji, Zhiguo Wang, Xiaoyu He, Ruilin Li, Xuebin Chi, Chengzhi Liang, Beifang Niu, Jun Xiao, Junming Li, Hong-Qing Ling
Molecular Plant
Abstract：Studying the regulatory mechanisms driving nitrogen use efficiency (NUE) of crops is important for sustaining agriculture and protecting environment. In this study, we generated a high-quality genome assembly for a high-NUE wheat cultivar Kenong 9204 and systematically analyzed the genes related to nitrogen uptake and metabolism. By comparative analysis, we found that the high-affinity nitrate transporter gene family expanded in Triticeae. Further study showed that subsequent functional differentiation endowed the expanded family members with salinity-inducible ability, which provides a genetic basis for improving the adaptability of wheat to nitrogen deficiency in various habitats. To explore the genetic and molecular mechanisms of high NUE, we compared the genomic and transcriptomic data between the high NUE cultivar KN9204 and a low-NUE cultivar Jing 411, and quantified their nitrogen accumulation under high and low nitrogen conditions. Compared with Jing 411, Kenong 9204 absorbed significantly more nitrogen at reproductive stage after shooting and accumulated in its shoots and seeds. Transcriptome data analysis revealed that nitrogen deficiency obviously suppressed the expression of the genes related to cell division in young spike of Jing 411, while such suppressed effect on gene expression was much less in Kenong 9204. In addition, Kenong 9204 maintained a longer time to keep a relative high expression of NPF genes than Jing 411 during seeds maturity. Physiological and transcriptome data revealed that Kenong 9204 was more tolerant to nitrogen deficiency than Jing 411, especially at its reproductive stage. The high NUE of KN9204 is an integrated effect controlled at different levels. Overall, our data obtained in this study provide a new insight to help understand the molecular mechanisms of NUE and a potential gene resource for improving wheat cultivars with higher NUE trait. |
