Search

Background: Corynespora leaf spot is a common leaf disease occurring in sesame, and the disease causes leaf yellowing and even shedding, which affects the growth quality of sesame. At present, the mechanism of sesame resistance to this disease is still unclear. Understanding the resistance mechanism of sesame to Corynespora leaf spot is highly important for the control of infection. In this study, the leaves of the sesame resistant variety (R) and the sesame susceptible variety (S) were collected at 0–48 hpi for transcriptome sequencing, and used a combined third-generation long-read and next-generation short-read technology approach to identify some key genes and main pathways related to resistance. Results: The gene expression levels of the two sesame varieties were significantly different at 0, 6, 12, 24, 36 and 48 hpi, indicating that the up-regulation of differentially expressed genes in the R might enhanced the resistance. Moreover, combined with the phenotypic observations of sesame leaves inoculated at different time points, we found that 12 hpi was the key time point leading to the resistance difference between the two sesame varieties at the molecular level. The WGCNA identified two modules significantly associated with disease resistance, and screened out 10 key genes that were highly expressed in R but low expressed in S, which belonged to transcription factors (WRKY, AP2/ERF-ERF, and NAC types) and protein kinases (RLK-Pelle_DLSV, RLK-Pelle_SD-2b, and RLK-Pelle_WAK types). These genes could be the key response factors in the response of sesame to infection by Corynespora cassiicola. GO and KEGG enrichment analysis showed that specific modules could be enriched, which manifested as enrichment in biologically important pathways, such as plant signalling hormone transduction, plant-pathogen interaction, carbon metabolism, phenylpropanoid biosynthesis, glutathione metabolism, MAPK and other stress-related pathways. Conclusions: This study provides an important resource of genes contributing to disease resistance and will deepen our understanding of the regulation of disease resistance, paving the way for further molecular breeding of sesame. [ABSTRACT FROM AUTHOR]

Penicillium sp. 44M-3, previously isolated from soil samples in Sanmenxia City (Henan Province, China), was identified as Penicillium aurantiogriseum Dierckx based on sequence analysis of ITS-rDNA, β-tubulin, and calmodulin. In co-culture assays against 14 pathogenic fungi, the inhibition ratios achieved by isolate 44M-3 ranged from 42.90% to 66.0%. Optimising the culture medium conditions to maximise the production of inhibitory substances increased the average inhibitory activity of the filtrate by 44.25% compared to that of the original culture filtrate. Isolate 44M-3 secreted extracellular enzymes such as protease, cellulase, and β-1,3-glucanase on agar plates. Treatment with a spore suspension of isolate 44M-3 significantly reduced the incidence of Sesame Fusarium wilt (P = 0.036) in pot experiments, achieving a maximum control efficacy of 75.88%, which did not differ significantly from carbendazim treatment (P = 0.292). Treatment with isolate 44M-3 spore suspension increased the root length of wheat and dry weight of whole sesame, maize, and tobacco plants, likely due to the isolate's ability to dissolve insoluble inorganic phosphorus and secrete siderophores and indole acetic acid. Consequently, isolate 44M-3 provides a promising candidate for plant growth promotion and prevention of sesame Fusarium wilt disease. [ABSTRACT FROM AUTHOR]

• Isolate 47M-1 from rhizosphere soil of tobacco was identified as Penicillium bilaiae. • 47M-1 inhibited growth of F. oxysporum and showed broad-spectrum antibiotic activity. • 47M-1 reduced disease incidence of Fusarium wilt of sesame with 50% control efficacy. • 47M-1 induced the defense genes in sesame against Fusarium wilt. • 47M-1 promoted plant growth by producing IAA, siderophore and dissolving phosphorus. The purpose of the present study was to explore the control of Fusarium wilt of sesame caused by Fusarium oxysporum via Penicillium sp. 47M-1. Isolate 47M-1 was isolated from rhizosphere soil samples of tobacco and identified as Penicillium bilaiae based on morphological characteristics and ITS-rDNA, β-tubulin and calmodulin sequences. Isolate 47M-1 inhibited the mycelial growth of F. oxysporum by 81.3% and overgrew the colonies of F. oxysporum in co-cultures. In a potting test, the control efficiency of isolate 47M-1 against Fusarium wilt of sesame was 50%, which was superior to that of Bacillus subtilis (P = 0.022). There was no significant difference (P = 0.068) in the control of Fusarium wilt between treatment with the fungicide carbendazim and treatment with isolate 47M-1. The results also showed that isolate 47M-1 and its culture filtrate significantly promoted the growth of sesame. Quantitative real time-PCR detection showed that the response-related genes NPR1 , Coi1 , PR1 , PR2 and PR3 were significantly upregulated under the combined stimulation of isolate 47M-1 and F. oxysporum compared to their expression under F. oxysporum treatment alone. In conclusion, isolate 47M-1 can control Fusarium wilt of sesame via multiple mechanisms, including competition, production of inhibitory substances, promotion of plant growth and induction of disease resistance. [ABSTRACT FROM AUTHOR]