文献类型： 外文期刊

作者： Quan, Jin ¹ ; Zheng, Weiwei ¹ ; Tan, Jingru ¹ ; Li, Zewei ¹ ; Wu, Meifang ¹ ; Hong, Seung-Beom ² ; Zhao, Yanting ³ ; Zhu, Zhujun ¹ ; Zang, Yunxiang ¹ ;

作者机构： 1.Zhejiang A&F Univ, Key Lab Qual & Safety Control Subtrop Fruit & Veg, Coll Hort Sci, Minist Agr & Rural Affairs,Collaborat Innovat Ctr, Hangzhou 311300, Peoples R China

2.Univ Houston Clear Lake, Dept Biotechnol, Houston, TX 77058 USA

3.Zhejiang Acad Agr Sci, Inst Vegetables, Hangzhou 310021, Peoples R China

关键词： glutamic acid; poly-gamma-glutamic acid; Chinese cabbage; heat stress; photosynthesis; antioxidant enzyme activity; biostimulant

期刊名称：INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES （ 影响因子：6.208； 五年影响因子：6.628 ）

ISSN：

年卷期： 2022 年 23 卷 19 期

页码：

收录情况： SCI

摘要： Heat stress is one of the most common agrometeorological risks in crop production in the middle and lower reaches of the Yangtze River in China. This study aimed to investigate whether glutamic acid (Glu) or poly-gamma-glutamic acid (gamma-PGA) biostimulants can improve the thermotolerance of a cool-season Chinese cabbage (Brassica rapa L. ssp. pekinensis) crop. Priming with Glu (2.0 mM) or gamma-PGA (20 mg.L-1) was conducted at the third leaf stage by applying as daily foliar sprays for 5 days before 5 days of heat stress (45 degrees C in 16-h light/35 degrees C in 8-h dark). Coupled with morphophysiological and biochemical analyses, transcriptomes of Glu or gamma-PGA-primed Chinese cabbage under heat stress were examined by RNA-seq analysis. The results showed that the thermotolerance conferred by Glu and gamma-PGA priming was associated with the increased parameters of vegetative growth, gas exchange, and chlorophyll fluorescence. Compared with the control, the dry weights of plants treated with Glu and gamma-PGA increased by 51.52% and 39.39%, respectively. Glu and gamma-PGA application also significantly increased the contents of total chlorophyll by 42.21% and 23.12%, and carotenoid by 32.00% and 24.00%, respectively. In addition, Glu- and gamma-PGA-primed plants markedly inhibited the levels of malondialdehyde, electrolyte leakage, and super-oxide anion radical, which was accompanied by enhanced activity levels of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD). Enrichment analysis of Kyoto Encyclopedia of Genes and Genomes (KEGG) categories within the differentially expressed genes (DEGs) functional clusters of RNA-seq data indicated that the expression levels of the genes for DNA replication, DNA repair system, linoleic acid metabolism, cysteine and methionine metabolism, glutathione metabolism, purine and pyrimidine metabolism, carotenoid biosynthesis, and plantpathogen interaction were commonly up-regulated by both Glu and gamma-PGA priming. Glu treatment enhanced the expression levels of the genes involved in aliphatic glucosinolate and 2-oxocarboxylic acid, while gamma-PGA treatment activated carotenoid cleavage reaction to synthesize abscisic acid. Taken together, both Glu and gamma-PGA have great potential for the preadaptation of Chinese cabbage seedlings to heat stress, with Glu being more effective than gamma-PGA.