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Transcripts and low nitrogen tolerance: Regulatory and metabolic pathways in sugarcane under low nitrogen stress

Author:
Yang, Yingying, Gao, Shiwu, Su, Yachun, Lin, Zhaoli, Guo, Jinlong, Li, Mingjie, Wang, Zhoutao, Que, Youxiong, Xu, Liping
Source:
Environmental and experimental botany 2019 v.163 pp. 97-111
ISSN:
0098-8472
Subject:
abscisic acid, biochemical pathways, enzyme activity, gene expression regulation, genes, glutamate-ammonia ligase, indole acetic acid, leaves, nitrogen, photosystem II, roots, sequence analysis, signal transduction, sugarcane, transcription factors
Abstract:
Understanding the molecular regulatory mechanism of physiological characteristics is essential to improve low nitrogen (N) tolerance in sugarcane. We selected sugarcane varieties ROC22 (low N-tolerant variety) and Badila (low N-sensitive variety) as experimental materials, and N sensitivity indexes (NSIs) of plant fresh weight and plant N accumulation in ROC22 was respectively 38.18% and 17.44% lower than that of Badila. Based on the morphological and physiological measurements and the expression of eight key genes in N metabolism, the leaves (6 h) and roots (3 h) of ROC22 and Badila under low N condition (0.6 mM N) were selected for RNA-Seq analysis. In the leaves and roots, the total and up-regulated numbers of differentially expressed genes (DEGs) in ROC22 was significantly higher than that of Badila. The specific DEGs in the ROC22 leaves mainly enriched in photosynthesis and N metabolism, whereas those in the ROC22 roots mainly enriched in N metabolism and the hormone signal transduction pathway. MYB was the largest differentially expressed transcription factor (TF) gene family in both varieties, followed by AP2-EREBP. In the leaves and roots of ROC22, several genes related to IAA and ABA hormone pathways, N assimilation process, and PSI and PSII of the photosynthesis pathways modulated the physiological characteristics under low N stress, correspondingly, IAA concentration increased by 11.47% (leaves) and 9.24% (roots), and glutamine synthetase (GS) enzyme activities increased by 28.13% (leaves) and 36.97% (roots), which may explain the observed differences in low N tolerance between ROC22 and Badila. This study has provided a basis for improvement of sugarcane in adapting to low N conditions.
Agid:
6393140