Transcriptomics and metabolomics analyses reveal the growth promoting effects of VOCs released by Clonostachys rosea f. catenulata on Arabidopsis Thaliana

Clonostachys rosea f. catenulate is a well-documented fungus, with extensive research reported on its antagonistic activity and mechanisms as a biocontrol. However, the role of its volatile organic compounds (VOCs) in plants growth regulation remains largely uninvestigated. This study reveals the effects of C. rosea f. catenulata VOCs on the growth of Arabidopsis thaliana and characterizes the VOCs composition using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). In addition, the integrated transcriptomic and metabolomic analyses elucidate the molecular mechanisms underlying plant growth promotion. The results showed that various indicators of A. thaliana, including root system, leaf area, chlorophyll content, biomass, water content, and siliqua number, were significantly enhanced under the influence of VOCs of C. rosea f. catenulata. Among them, the most substantial changes were observed in root-related parameters, with the main root length, number of lateral roots and lateral root length increasing by 137.19%, 178.34%, and 422.20%, respectively. Additionally, leaf area and aboveground fresh weight increased by 64.36% and 26.79%, respectively and the chlorophyll-related indicators increased by more than 15.00%. Alcohols were identified as major components of VOCs in C. rosea f. catenulata. Transcriptome analysis revealed 1,228 differentially expressed genes (DEGs), with 476 being significantly upregulated and 752 downregulated. A considerable proportion of these DEGs were predominantly associated with plant defense responses through phenylpropanoid biosynthesis, plant hormone signal transduction and secondary metabolite biosynthesis was revealed by functional annotation. Metabolome analysis identified 20 differentially expressed metabolites (DEMs), primarily consisting of amino acids, organic acids and flavonoids. This uniquely designed interesting study advances our knowledge regarding the physiological and molecular mechanisms underlying the effect of plant growth-promoting C. rosea f. catenulata VOCs, providing a strong foundation for the sustainable agricultural application of C. rosea f. catenulata VOCs in crop enhancement and resilience.