Dong Dan, Li Maoying, Zhang Taotao, Niu Zhenfeng, Xue Guoping, Bai Hongmei, Zhao Wenyu, Yu Jiajia, Jiang Wei, Wu Huiling
Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Key Laboratory of Environment Friendly Management on Fruit and Vegetable Pests in North China (Co-Construction by Ministry and Province), Ministry of Agriculture and Rural Affairs, Beijing 100097, China.
National Watermelon and Melon Improvement Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China.
Plants (Basel). 2023 Nov 8;12(22):3796. doi: 10.3390/plants12223796.
strain 11F has inhibitory effects on many phytopathogenic fungi and improves the establishment and biomass yield of switchgrass. However, the antagonistic effects of strain 11F on wilt of watermelon and its secondary metabolites that contribute to its biocontrol activity are poorly understood. We evaluated the antagonistic and growth-promoting effects of strain 11F and conducted a transcriptome analysis to identify the metabolites contributing to antifungal activity. Strain 11F had marked inhibitory effects on six fungal pathogens. The incidence of wilt of watermelon seedlings was decreased by 46.02%, while watermelon seedling growth was promoted, as indicated by plant height (8.7%), fresh weight (23.1%), and dry weight (60.0%). Clean RNA-sequencing data were annotated with 7553 functional genes. The 2582 differentially expressed genes (DEGs) detected in the Control vs. Case 2 comparison were divided into 42 subcategories of the biological process, cellular component, and molecular function Gene Ontology categories. Seven hundred and forty functional genes (55.47% of the DEGs) were assigned to Kyoto Encyclopedia of Genes and Genomes metabolic pathways, reflecting the complexity of the strain 11F metabolic regulatory system. The expression level of the gene , which encodes an enzyme essential for phenazine-1-carboxylic acid (PCA) synthesis, was downregulated 3.7-fold between the 24 h and 48 h fermentation time points, suggesting that strain 11F can produce phenazine compounds. A phenazine compound from 11F was isolated and identified as phenazine-1-carboxamide (PCN), which contributed to the antagonistic activity against f. sp. . PCA was speculated to be the synthetic precursor of PCN. The downregulation in expression might be associated with the decrease in PCA accumulation and the increase in PCN synthesis in strain 11F from 24 to 48 h. 11F protects watermelon seedlings from wilt of watermelon and promotes seedling growth. The transcriptome analysis of strain 11F provides insights into the synthesis of PCN, which has antifungal activity against f. sp. of watermelon.
菌株11F对多种植物病原真菌具有抑制作用，并能促进柳枝稷的定植和生物量产量。然而，菌株11F对西瓜枯萎病的拮抗作用及其有助于生物防治活性的次生代谢产物尚不清楚。我们评估了菌株11F的拮抗和促生长作用，并进行了转录组分析，以确定有助于抗真菌活性的代谢产物。菌株11F对六种真菌病原体具有显著的抑制作用。西瓜幼苗枯萎病的发病率降低了46.02%，同时西瓜幼苗生长得到促进，如株高（8.7%）、鲜重（23.1%）和干重（60.0%）所示。干净的RNA测序数据用7553个功能基因进行了注释。在对照与病例2比较中检测到的2582个差异表达基因（DEG）被分为生物过程、细胞成分和分子功能基因本体论类别的42个子类别。740个功能基因（占DEG的55.47%）被分配到京都基因与基因组百科全书代谢途径，反映了菌株11F代谢调控系统的复杂性。编码吩嗪-1-羧酸（PCA）合成必需酶的基因在24小时和48小时发酵时间点之间表达水平下调了3.7倍，表明菌株11F可以产生吩嗪化合物。从11F中分离出一种吩嗪化合物并鉴定为吩嗪-1-甲酰胺（PCN），它有助于对西瓜枯萎病菌的拮抗活性。推测PCA是PCN的合成前体。基因表达的下调可能与24至48小时菌株11F中PCA积累的减少和PCN合成的增加有关。11F保护西瓜幼苗免受西瓜枯萎病侵害并促进幼苗生长。菌株11F的转录组分析为PCN的合成提供了见解，PCN对西瓜枯萎病菌具有抗真菌活性。
