Xylella fastidiosa’s relationships: the bacterium, the host plants, and the plant microbiome

Abstract

Summary Xylella fastidiosa is the causal agent of important crop diseases and is transmitted by xylem‐sap‐feeding insects. The bacterium colonizes xylem vessels and can persist with a commensal or pathogen lifestyle in more than 500 plant species. In the past decade, reports of X. fastidiosa across the globe have dramatically increased its known occurrence. This raises important questions: How does X. fastidiosa interact with the different host plants? How does the bacterium interact with the plant immune system? How does it influence the host’s microbiome? We discuss recent strain genetic typing and plant transcriptome and microbiome analyses, which have advanced our understanding of factors that are important for X. fastidiosa plant infection.

Xylella fastidiosa Infection Reshapes Microbial Composition and Network Associations in the Xylem of Almond Trees

“…The decrease in the relative abundance of specific microbial taxa detected in our study in X. fastidiosa trees may be explained by: (i) the displacement of the natural xylem microbiota due to niche exclusion ( X. fastidiosa colonizes and occludes xylem vessels forming microcolonies); (ii) the secretion by X. fastidiosa of specific molecules directly or in outer membrane vesicles with antimicrobial, signaling, and cell wall degrading activity ( Feitosa-Junior et al, 2019 ; de Souza et al, 2020 ) can induce a direct modification of the xylem microbiome or induce changes if used as nutrient sources; and/or (iii) the triggering of a series of host physiological responses that result in a decrease in the abundance of specific components of the xylem microbiome. Thus, the interaction between X. fastidiosa and the plant xylem microbiome is bidirectional and there is still a need to unravel the molecular mechanisms underlying these interactions ( Landa et al, 2022 ). These hypotheses emphasize the need to expand our knowledge on the changes that may take place in xylem microbial communities after infection by vascular plant pathogens ( Anguita-Maeso et al, 2021b ).…”

“…morus ) ( Almeida and Nunney, 2015 ). Furthermore, each subspecies consists of multiple genetic lineages, grouped as sequence types (ST), each with different host ranges and virulence, although there is some host overlap and most of them infect several hosts ( Sicard et al, 2018 ; Nunney et al, 2019 ; Landa et al, 2022 ).…”

“…Some studies have described the microbial community structure and composition within xylem vessels and its relationship to plant health and crop productivity (e.g., Deyett et al, 2017 ; Fausto et al, 2018 ; Deyett and Rolshausen, 2019 ; Anguita-Maeso et al, 2020 , 2021a , b ; Zicca et al, 2020 ; Haro et al, 2021 ). However, a very scarce number of studies have focused on the relationships between X. fastidiosa and xylem sap microbiota to assess the level of dysbiosis and the potential role of microbial endophytes in protecting host plants from disease development or stimulating plant immunity ( Lacava et al, 2004 ; Azevedo et al, 2016 ; Deyett et al, 2019 ; Pacifico et al, 2019 ; Giampetruzzi et al, 2020 ; Vergine et al, 2020 ; Landa et al, 2022 ). For instance, Lacava et al (2004) reported in vitro growth stimulation of X. fastidiosa by Methylobacterium extorquens and inhibition by Curtobacterium flaccumfaciens , two plant endophytes ; whereas Deyett et al (2017) found that the two endophytic bacteria Pseudomonas fluorescens and Achromobacter xylosoxidans showed significant negative correlations in their abundance with X. fastidiosa .…”

Thidiazuron: New Trends and Future Perspectives to Fight Xylella fastidiosa in Olive Trees

“…TDZ exhibits both auxin-an cytokinin-like effects on growth and differentiation of cultured explants, although, und Several studies are being carried out to understand the underlying causes of Xf emergence and spread among olive trees. Nevertheless, several important questions regarding Xf remain unsolved, e.g., how it interacts with the different host plants, with the plant immune system and how it influences the host's microbiome [38]. Sanitation of infected olive trees is unfeasible [39], and very few phyto-therapeutics were evaluated to mitigate OQDS disease.…”

CRISPR/Cas Genome Editing Technologies for Plant Improvement against Biotic and Abiotic Stresses: Advances, Limitations, and Future Perspectives

“…Plants produce food, fuel, and feed, which are essential in daily human and animal life for nourishment and growth. In the process of plant growth, they will be affected by a variety of biological stresses (bacteria, viruses, fungi, and insects) and abiotic stresses [ 1 , 2 , 3 , 4 , 5 ]. Due to continuous global climate change and anthropogenic activity, the impact of abiotic stresses on crop growth and development is becoming more serious.…”