Nitrogen assimilation and gene regulation of two Kentucky bluegrass cultivars differing in response to nitrate supply
Nitrogen assimilation and gene regulation of two Kentucky bluegrass cultivars differing in response to nitrate supply
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DOI：
10.1016/j.scienta.2021.110315
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发表时间：
2021-10
影响因子：
4.3
通讯作者：
Xiaoyang Sun;Qianjiao Zheng;L. Xiong;Fuchun Xie;Xun Li;Yong Li;Lu Zhang;S. Saud;Zhixin Guo-Z
中科院分区：
文献类型：
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作者：
Xiaoyang Sun;Qianjiao Zheng;L. Xiong;Fuchun Xie;Xun Li;Yong Li;Lu Zhang;S. Saud;Zhixin Guo-Z
肯塔基州早熟禾（Poa pratensisL.）冷季型草坪草是世界上最受欢迎的冷季型草坪草之一，但该物种响应低氮（N）的机制尚不清楚。在这项研究中，我们描述了两个品种'蓝月亮'和'巴林'不同的形态，染色体，生理和分子属性和植物对氮供应的反应。蓝月亮比巴林更耐低氮，表现出更好的草坪质量（TQ），更高的光合能力，氮还原酶和合成酶的活性和氮利用效率（NUE）。基因表达谱分析表明，低氮胁迫下蓝月亮和巴林分别存在838个和10,156个差异表达基因（DEG），这些差异表达基因主要集中在氮代谢、丙酮酸代谢和光合固碳三条途径。这些与碳代谢相关的基因在蓝月亮中高表达，蓝月亮能产生更多的NADPH，因此比巴林更高的氮还原。细胞质PpGS1.3基因可能是导致Balin和Bluemoon对氮反应差异的关键基因。该基因与PpGS1.1具有相似的理化性质，与PpGS 2具有相似的蛋白质三级结构。R2 R3-MYB转录因子与PpGS1.3启动子结合，增强了GS/GOGAT循环的效率。这些结果表明，在提高蓝月亮品种耐低氮和氮利用效率的关键分子调控功能。这一结果有助于阐明肯塔基州早熟禾耐低氮的机制，从而促进氮素利用效率的遗传改良，促进低投入草坪草的管理。
Kentucky bluegrass (Poa pratensisL.) is one of the most popular cool-season turfgrasses worldwide, but mechanisms of this species in response to low nitrogen (N) still remain unclear. In this study, we characterized two cultivars ‘Bluemoon’ and ‘Balin’ differing in morphological, chromosomal, physiological and molecular attributes and in plant response to N supply. Bluemoon was more tolerant to low N than Balin by exhibiting better turf quality (TQ), and higher photosynthetic ability, activities of N reductases and synthetases, and nitrogen use efficiency (NUE). Gene expression profiling showed the existence of 838 and 10,156 differentially expressed genes (DEGs) in Bluemoon and Balin respectively during low N stress, and these DEGs were highly enriched in ‘Nitrogen metabolism’, ‘Pyruvate metabolism’ and ‘Carbon fixation in photosynthetic’ pathways. Those identified genes related to carbon (C) metabolism were highly expressed in Bluemoon, which could generate more NADPH, hence more N reduction than in Balin. CytoplasmicPpGS1.3gene is viewed to likely play a key role in leading to different N responses between Balin and Bluemoon. This gene is detected to have similar physicochemical properties toPpGS1.1, while sharing a similar tertiary structure of protein to PpGS2. Moreover,R2R3-MYBtranscription factors were predicted to bind the promoter ofPpGS1.3to enhance the efficiency of theGS/GOGATcycle. These results suggest the functioning of crucial molecular regulations for improving the varietal tolerance to low N and the NUE in Bluemoon. The findings may help elucidate the low N tolerance mechanisms in Kentucky bluegrass and therefore facilitate genetic improvement of NUE aiming to promote low-input turfgrass management.