Ralstonia solanacearum Differentially Colonizes Roots of Resistant and Susceptible Tomato Plants

Abstract

Ralstonia solanacearum is the causal agent of bacterial wilt and infects over 200 plant species in 50 families. The soilborne bacterium is lethal to many solanaceous species, including tomato. Although resistant plants can carry high pathogen loads (between 10 and 10 CFU/g fresh weight), the disease is best controlled by the use of resistant cultivars, particularly resistant rootstocks. How these plants have latent infections yet maintain resistance is not clear. R. solanacearum first infects the plant through the root system and, thus, early root colonization events may be key to understanding resistance. We hypothesized that the distribution and timing of bacterial invasion differed in roots of resistant and susceptible tomato cultivars. Here, we use a combination of scanning electron microscopy and light microscopy to investigate R. solanacearum colonization in roots of soil-grown resistant and susceptible tomato cultivars at multiple time points after inoculation. Our results show that colonization of the root vascular cylinder is delayed in resistant 'Hawaii7996' and that, once bacteria enter the root vascular tissues, colonization in the vasculature is spatially restricted. Our data suggest that resistance is due, in part, to the ability of the resistant cultivar to restrict bacterial root colonization in space and time.

Design, synthesis and antibacterial activities against Xanthomonas oryzae pv. oryzae, Xanthomonas axonopodis pv. Citri and Ralstonia solanacearum of novel myricetin derivatives containing sulfonamide moiety

“…o ., a bacteria that can cause damage at any stage of the life cycle, resulting in a serious decline in the crop yield . One of the main diseases affecting tobacco plants in tropical and subtropical regions (tobacco wilt) is caused by Ralstonia solanacearum . Prevention of these diseases mainly relies on antibiotics (i.e.…”

“…1,2 One of the main diseases affecting tobacco plants in tropical and subtropical regions (tobacco wilt) is caused by Ralstonia solanacearum. 3 Prevention of these diseases mainly relies on antibiotics (i.e. streptomycin sulfate) and chemical preservatives (i.e.…”

The critical role of biofilms in bacterial vascular plant pathogenesis

“…Incipient biofilms are formed with active cell growth and division (Khokhani et al , ). This process leads to the formation of thicker mats in the late stages that eventually clog the sap flow in the xylem (Caldwell et al , ).…”

“…Incipient biofilms are formed with active cell growth and division (Khokhani et al, 2017). This process leads to the formation of thicker mats in the late stages that eventually clog the sap flow in the xylem (Caldwell et al, 2017). Colonization at the initial stage is facilitated by fimbrial and non-fimbrial adhesins as well as by lectins, hemagglutinins and other molecules that enable bacterial cell attachment to plant tissues.…”

“…The biofilm can grow to the point of clogging the entire xylem and obstructing sap flow. This mechanism is the major cause of xylem occlusion in R. solanacearum (Caldwell et al, 2017) and X. fastidiosa (Killiny et al, 2013). Leaves may be severely damaged, which eventually leads to the impairment of the whole plant and its death (Yadeta & J Thomma, 2013).…”