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Article|30 Aug 2022|OPEN
Glutamine synthetase gene PpGS1.1 negatively regulates the powdery mildew resistance in Kentucky bluegrass
Xiaoyang Sun1 , Fuchun Xie1 , , Yajun Chen1,2 , , Zhixin Guo2 , Lili Dong2 , Ligang Qin1 , Zhenjie Shi2,3 , Liangbing Xiong2 and Runli Yuan2 , Wenjing Deng2 , Yiwei Jiang,4
1College of Animal Science and Technology, Northeast Agricultural University, Harbin, China
2College of Horticulture, Northeast Agricultural University, Harbin, China
3College of Horticulture, Nanjing Agricultural University, Nanjing, China
4Department of Agronomy, Purdue University, West Lafayette, IN, USA
*Corresponding author. E-mail: xfc204309@neau.edu.cn,chenyajun622@neau.edu.cn

Horticulture Research 9,
Article number: uhac196 (2022)
doi: https://doi.org/10.1093/hr/uhac196
Views: 226

Received: 03 Jan 2022
Accepted: 26 Aug 2022
Published online: 30 Aug 2022

Abstract

Excessive nitrogen (N) application may induce powdery mildew (PM) in perennial grasses, but the resistance mechanisms to PM remain unclear. This study evaluated the physiological and molecular mechanisms of PM resistance affected by N supplies in Kentucky bluegrass (Poa pratensis L.). Cultivar ‘Bluemoon’ (N tolerant) and ‘Balin’ (N sensitive) were treated with low N (0.5 mM), normal N (15 mM), and high N (30 mM) for 21 d in a greenhouse. With increasing N levels, the disease growth was more severe in ‘Balin’ than in ‘Bluemoon’. RNA-seq and weighted gene coexpression network analysis revealed that the PpGS1.1 gene encoding glutamine synthetase was a potential hub gene for PM resistance after comparisons across cultivars and N treatments. The N metabolism pathway was connected with the plant–pathogen interaction pathway via PpGS1.1. The expression of PpGS1.1 in rice protoplasts indicated that the protein was located in the nucleus and cytoplasm. Overexpression of PpGS1.1 in wild-type Kentucky bluegrass increased carbon and N contents, and the transgenic plants became more susceptible to PM with a lower wax density. The most differentially expressed genes (DEGs) for N metabolism were upregulated and DEGs for fatty acid metabolism pathway were downregulated in the overexpression lines. The results elucidated mechanisms of PM resistance in relation to N metabolism in Kentucky bluegrass.