1,721,045 research outputs found
Is the ascorbate system involved in the induction of the oxidative burst by oligogalacturonides and salicylic acid?
No full textBologn
How do pectin methylesterases and their inhibitors affect the spreading of tobamovirus?
Full text linkAfter replication in the cytoplasm, viruses spread from the infected cell into the neighboring cells through plasmodesmata, membranous channels embedded by the cell wall. As obligate parasites, viruses have acquired the ability to utilize host factors that unwillingly cooperate for the viral infection process. For example, the viral movement proteins (MP) interacts with the host pectin methylesterase (PME) and both proteins cooperate to sustain the viral spread. However, how and where PMEs interact with MPs and how the PME/MP complexes favor the viral translocation is not well understood. Recently, we demonstrated that the overexpression of PME inhibitors (PMEIs) in tobacco and Arabidopsis plants limits the movement of Tobacco mosaic virus and Turnip vein clearing virus and reduces plant susceptibility to these viruses. Here we discuss how overexpression of PMEI may reduce tobamovirus spreading
Transgenic Expression of Pectin Methylesterase Inhibitors in Arabidopsis and Tobacco limits Tobamovirus spreading
No full textViral infection is a complex process influenced by the balance of virus-encoded proteins and host factors which support virus replication, cell-to-cell and long distance movement through the plant. Virus-encoded movement proteins (MPs) are necessary to allow cell-to-cell spread through plasmodesmata (PD). The interaction of MP with plant pectin methylesterase (PME) is required for Tobacco mosaic virus (TMV) local spreading in tobacco.
The viral exit out of the vascular system is also partly PME-dependent. Pectin demethylation directed by PME is likely to be a source of methanol that has been recently found to facilitate TMV spreading by triggering PD dilation. We here report that the expression of a PME inhibitor from Actinidia chinensis (AcPMEI) in Nicotiana tabacum decreases the overall PME activity and increases the level of pectin methylesterification of the wall without affecting plant morphology and development. After inoculation with TMV the transformed plants expressing AcPMEI exhibited a significant delay of viral spreading. A reduced susceptibility against Turnip vein clearing virus (TVCV) infection was also observed in Arabidopsis plants overexpressing the AtPMEI-2 inhibitor. Overall, our results indicate PMEIs as efficient tools to limit Tobamovirus infection
Polygalacturonases, polygalacturonase-inhibiting proteins and pectic oligomers in plant-pathogen interactions
No full textPolygalacturonases (PGs) are produced by fungal pathogens during early plant infection and are believed to be important pathogenicity
factors. Polygalacturonase-inhibiting proteins (PGIPs) are plant defense proteins which reduce the hydrolytic activity of endoPGs and favor
the accumulation of long-chain oligogalacturonides (OGs) which are elicitors of a variety of defense responses. PGIPs belong to the
superfamily of leucine reach repeat (LRR) proteins which also include the products of several plant resistance genes. A number of evidence
demonstrates that PGIPs efficiently inhibit fungal invasion
Pectin methylesterases affect plant resistance to pathogens
No full textPectin is synthesized in a highly methyl esterified form and is de-esterified in muro by pectin methyl esterases (PMEs). The degree and pattern of methyl esterification affect the cell wall structure and properties with consequences on their resistance to pathogens. We show that PME is required for the initial plant tissue colonization by fungal and bacterial necrotrophs, making pectin more susceptible to the action of the hydrolytic enzymes of the pathogens. We have reduced the susceptibility of plants to pathogens by increasing the methyl esterification of pectin through the overexpression of PME inhibitors (PMEI). A natural Arabidopsis ecotype, showing a higher pectin esterification and lower homogalacturonan content than the reference ecotype Col-0 is more resistant to necrotrophic fungal and bacterial pathogens. PME is also required for viral cell-to-cell and long-distance movement of plant virus. Our results support the notion that PME activity affects the mechanical properties of cell wall and plant resistance against pathogens
PECTIN METHYLESTERASE INHIBITORS LIMIT TOBAMOVIRUS SPREADING IN TOBACCO AND ARABIDOPSIS
No full textPlant infection by a virus is a complex process influenced by virus-encoded factors and host components that support replication and movement. Critical factors for a successful infection are the movement proteins (MPs) that modify the size exclusion limit of plasmodesmata during the cell-to-cell movement. Pectin methylesterases (PMEs) was shown to interact in vitro with the MP of different viruses and this interaction was proposed to be necessary for Tobacco mosaic virus (TMV) spreading as well as for its systemic movement through the host vasculature. Here we report that the ectopic expression of a PME inhibitor from Actinidia chinensis in Nicotiana tabacum significantly delays the TMV cell-to-cell and systemic spreading. A reduced susceptibility against Turnip vein clearing virus was also observed in Arabidopsis plants overexpressing a PME inhibitor from Arabidopsis. Overall, our results strongly support the important roles of PMEs in viral movement and indicate PME inhibitors as a useful tool to limit virus infection
Host pectin methylesterase plays a role in the susceptibility to necrotrophic pathogens
No full textThe host cell wall is a primary target during growth of
necrotrophic pathogens. During the first stages of infection,
pectin, one of the main components of the plant cell wall, is degraded
by pectinolytic enzymes produced by the majority of fungal
and bacterial pathogens. Some evidence indicates that variation
of the pectin structure and composition may cause an altered
disease response upon infection with pathogens. Pectin is synthesized
and secreted into the cell wall in a highly methylesterified
form and, soon thereafter, deesterified in muro by pectin
methylesterases (PMEs). The action of PME makes pectin susceptible
to degradation by enzymes such as endo-polygalacturonases
(PGs) and pectate lyases (PELs). Endogenous PME activity
is controlled through the interaction with the pectin
methylesterase inhibitor (PMEI). PMEI over-expression and
PME knockout have been used to stably increase pectin
methylesterification in Arabidopsis plants. We have shown that
the increase of pectin methylesterification and the lack of a specific
PME activity correlate to a decreased susceptibility of Arabidopsis
to the necrotrophic pathogens Pectobacterium carotovorum
and Botrytis cinerea. The reduced symptoms of transformed
plants have been related to the inability of the pathogens to take
advantage of host PMEs and to their impaired ability to grow on
methylesterified pectins
- …
