Study on the interaction mechanism between Crocus sativus and Fusarium oxysporum based on dual RNA-seq

A Dual RNA-Seq Analysis Revealed Dynamic Arms Race during the Infestation of Wheat by the English Grain Aphid (Sitobion avenae)

Sitobion avenae is an important pest that threatens the safety of wheat production in China. However, the resistance mechanisms of wheat to S. avenae are not well understood at present. In this study, we investigated the mechanisms of interaction between wheat and S. avenae at four infestation time points (6, 24, 48, and 72 hpi) using a high-resolution time series dual transcriptomic analysis. The results showed that plant hormone signal transduction, phenylpropanoid biosynthesis, and flavonoid biosynthesis pathways were significantly activated in the wheat spike of Lunxuan144 during S. avenae infestation. Meanwhile, the functional analysis of the S. avenae transcriptome revealed that some secretory proteins participated in wheat-S. avenae interaction. This study sheds light on the arms race process between S. avenae and wheat, laying the foundation for the green prevention of S. avenae and providing a theoretical basis for mining the key functional genes in both wheat and S. avenae.

The Ubiquitous Wilt-Inducing Pathogen Fusarium oxysporum-A Review of Genes Studied with Mutant Analysis

Fusarium oxysporum is one of the most economically important plant fungal pathogens, causing devastating Fusarium wilt diseases on a diverse range of hosts, including many key crop plants. Consequently, F. oxysporum has been the subject of extensive research to help develop and improve crop protection strategies. The sequencing of the F. oxysporum genome 14 years ago has greatly accelerated the discovery and characterization of key genes contributing to F. oxysporum biology and virulence. In this review, we summarize important findings on the molecular mechanisms of F. oxysporum growth, reproduction, and virulence. In particular, we focus on genes studied through mutant analysis, covering genes involved in diverse processes such as metabolism, stress tolerance, sporulation, and pathogenicity, as well as the signaling pathways that regulate them. In doing so, we hope to present a comprehensive review of the molecular understanding of F. oxysporum that will aid the future study of this and related species.

Molecular warfare between pathogenic Fusarium oxysporum R1 and host Crocus sativus L. unraveled by dual transcriptomics

KEY MESSAGE

Phenylpropanoid biosynthesis and plant-pathogen interaction pathways in saffron and cell wall degrading enzymes in Fusarium oxysporum R1 are key players involved in the interaction. Fusarium oxysporum causes corm rot in saffron (Crocus sativus L.), which is one of the most devastating fungal diseases impacting saffron yield globally. Though the corm rot agent and its symptoms are known widely, little is known about the defense mechanism of saffron in response to Fusarium oxysporum infection at molecular level. Therefore, the current study reports saffron-Fusarium oxysporum R1 (Fox R1) interaction at the molecular level using dual a transcriptomics approach. The results indicated the activation of various defense related pathways such as the mitogen activated protein kinase pathway (MAPK), plant-hormone signaling pathways, plant-pathogen interaction pathway, phenylpropanoid biosynthesis pathway and PR protein synthesis in the host during the interaction. The activation of pathways is involved in the hypersensitive response, production of various secondary metabolites, strengthening of the host cell wall, systemic acquired resistance etc. Concurrently, in the pathogen, 60 genes reported to be linked to pathogenicity and virulence has been identified during the invasion. The expression of genes encoding plant cell wall degrading enzymes, various transcription factors and effector proteins indicated the strong pathogenicity of Fusarium oxysporum R1. Based on the results obtained, the putative molecular mechanism of the saffron-Fox R1 interaction was identified. As saffron is a male sterile plant, and can only be improved by genetic manipulation, this work will serve as a foundation for identifying genes that can be used to create saffron varieties, resistant to Fusarium oxysporum infection.

Isolation, Identification, and Determination of the Virulence of the Causal Agents of Corm Rot of Saffron (Crocus sativus L.) in Valle de Uco, Argentina

Saffron (Crocus sativus L.) presents an attractive opportunity for diversifying production and adding value, particularly for small-scale growers and family-based agriculture. However, the agamic propagation of the crop through corms raises concerns regarding disease dispersion. During the summers of 2013 and 2015, symptoms of corm rot were observed in saffron crops in La Consulta, Valle de Uco, Argentina. These symptoms manifested in the form of wilting plants and red-coloured areas on the surface of the corms, in some cases affecting deeper regions. This study aimed to isolate and identify the causal agent responsible for saffron corm rot while also comparing the virulence of four strains isolated on saffron plants. Consistent isolation of Fusarium spp. colonies from affected corms confirmed its association with the disease. The obtained isolates were inoculated into healthy corms, and the reproduction of symptoms was confirmed, as well as subsequent pathogen re-isolation. Morphological and molecular characterisation of the strains was performed using rDNA gene sequencing. Furthermore, disease progression was assessed with fitting epidemiological models to empirical data, which served as estimators of fungal strain aggressiveness. The results conclusively identified Fusarium oxysporum Schltdl. as the causal agent of corm rot, and variations in virulence were observed among the strains on the host plant. After basic molecular and pathological studies, it is postulated that the fungal strains possibly belong to the forma specialis gladioli, but further studies are necessary to confirm that. The present study provides findings that highlight the importance of early detection and the preservation of pathogen-free fields to sustain saffron cultivation. These findings may constitute the initial step for future projects aimed at understanding the epidemiology of the disease better, determining the species/races of the pathogen, and developing effective management strategies.