Li Zhang,Yizhong Huang,Zhuaquan Xiao,Xuezhen Feng,Ji Zhang,Shangxing Chen,Haohua He,Shengliang Liao,Zongde Wang,Hongyan Si
Rhizoctonia solani ( R. solani ) is a phytopathogen that extensively affects crops, leading to plant diseases and reducing crop yields, which jeopardizes food security. β-pinene is a major component of turpentine oil and serves as a lead compound for developing new fungicides. Herein, β-pinene derivatives containing quaternary ammonium scaffold were synthesized in our laboratory, exhibiting broad-spectrum antifungal activity, especially compound bis-hydronopyl dimethyl ammonium bromide ( b-HDAB ). This study aimed to investigate the potential antifungal mechanism of b-HDAB against R. solani . The b-HDAB displayed promising antifungal activities in vitro (EC 50 = 10.20 mg/L and EC 90 = 18.43 mg/L). Its in vivo curative effects (59.82 %) at a dose of 500 mg/L were as remarkable as those of the positive control of validamycin·bacillus (60.58 %). Mechanistically, b-HDAB altered the normal morphology of R. solani mycelium and disrupted its ultrastructure. Meanwhile, b-HDAB increased the relative electrical conductivity of R. solani mycelium, leading to leakage of nucleic acids and proteins from the mycelium. In addition, b-HDAB inhibited the tricarboxylic acid cycle (TCA)-related enzymes, and b-HDAB might exhibit favorable binding stability, potentially through the formation of a pi-cation interaction with the arginine residue (RP357) of pyruvate dehydrogenase (PDH). Metabolomics analysis demonstrated that the content of unsaturated fatty acids of R. solani increased after treatment with b-HDAB , and transcriptomic analysis indicated that b-HDAB destroyed the energy metabolism. These results might guide the development of b-HDAB as an alternative antifungal agent.
Nanocarrier-mediated delivery of double-stranded RNA (dsRNA) is a promising strategy for plant disease control. Our previous study has shown that the self-assembled ε-poly- l -lysine/carboxymethyl chitosan (ε-PL@CMCS) nanocarrier significantly improves the efficiency of RNA interference (RNAi) against Rhizoctonia solani AG3 TB. However, the molecular mechanisms underlying this enhancement and the potential ecological impacts on phyllosphere microbial communities remain unclear. In this study, we confirmed that ds RsGH1 @ε-PL@CMCS had no adverse effects on the growth and development of plants. Transcriptome analysis revealed that DEGs were significantly enriched in ‘SNARE interactions in vesicular transport’ pathway. Among them, ds RsGH1 @ε-PL@CMCS specifically upregulate the vesicle transport protein SEC22 in Nicotiana tabacum. Surface plasmon resonance (SPR) assay demonstrated that the ds RsGH1 @ε-PL@CMCS binds to SEC22 protein with 7.6-fold higher affinity than that of the naked ds RsGH1 . Silencing SEC22 in the ds RsGH1 @ε-PL@CMCS treatment reduced the silencing efficiency of RsGH1 from 53.3% to 39%, confirming its essential role. Concurrently, high-throughput sequencing revealed that SIGS treatments did not disrupt bacterial community structure but increased fungal diversity and suppressed the pathogen, while enriching beneficial fungi such as Tulasnella . Our findings elucidate a molecular link between nano-bioprotectant ds RsGH1 @ε-PL@CMCS-enhanced RNAi and host vesicle transport, while confirming the biocompatible and microbiome-modulating potential. This provides a dual perspective for developing efficient and sustainable RNAi-based strategies for protecting plants.
危险品化学品经营许可证（带存储）