The cytoskeleton enhances gene expression in the response to the Harpin elicitor in grapevine

Abstract

The cytoskeleton undergoes dramatic reorganization during plant defence. This response is generally interpreted as part of the cellular repolarization establishing physical barriers against the invading pathogen. To gain insight into the functional significance of cytoskeletal responses for defence, two Vitis cell cultures that differ in their microtubular dynamics were used, and the cytoskeletal response to the elicitor Harpin in parallel to alkalinization of the medium as a fast response, and the activation of defence-related genes were followed. In one cell line derived from the grapevine cultivar ‘Pinot Noir’, microtubules contained mostly tyrosinylated α-tubulin, indicating high microtubular turnover, whereas in another cell line derived from the wild grapevine V. rupestris, the α-tubulin was strongly detyrosinated, indicating low microtubular turnover. The cortical microtubules were disrupted and actin filaments were bundled in both cell lines, but the responses were elevated in V. rupestris as compared with V. vinifera cv. ‘Pinot Noir’. The cytoskeletal responsiveness correlated with elicitor-induced alkalinization and the expression of defence genes. Using resveratrol synthase and stilbene synthase as examples, it could be shown that pharmacological manipulation of microtubules could induce gene expression in the absence of elicitor. These findings are discussed with respect to a role for microtubules as positive regulators of defence-induced gene expression.

Response of Vitis vinifera cell cultures to Eutypa lata and Trichoderma atroviride culture filtrates: expression of defence-related genes and phenotypes

“…A switch from flavonoid synthesis to stilbene synthesis signifies a shift to defence metabolism. Similar results were also obtained with grapevine cell culture elicited by the bacterial effector Harpin (Qiao et al 2010) and in grapevine leaves elicited by Plasmopara (Pl.) viticola (causal organism of downy mildew) (Vannozzi et al 2012).…”

“…Comparative studies of the response of cell lines of susceptible V. vinifera and generally resistant V. rupestris to a bacterial effector, Harpin elicitor, also eluded to similar conclusions. Both Vitis species responded with an increased STS transcription, but levels were lower in susceptible V. vinifera compared to V. rupestris and resveratrol accumulation in the cells followed a similar pattern as the transcription (Qiao et al 2010;Chang et al 2011).…”

ACTIN DEPOLYMERIZING FACTOR4 Regulates Actin Dynamics during Innate Immune Signaling in Arabidopsis

“…Significantly, overexpression of AC or treatment with actin disrupting drugs facilitates the invasion of plant tissues by several fungal and bacterial species (Miklis et al, 2007;Porter et al, 2012;Henty-Ridilla et al, 2013a). In contrast with increased actin abundance during host-microbe interactions, certain signals from pathogenic fungi like the Verticillium dahlia toxin or the bacterial Harpin elicitor can stimulate the dose-dependent destruction of cortical actin filaments (Yuan et al, 2006;Qiao et al, 2010). Moreover, a study with flg22 treatment of tobacco (Nicotiana tabacum) Bright Yellow-2 cells failed to demonstrate any quantitative changes in actin organization, perhaps due to cell type-specific signaling cascades (Guan et al, 2013).…”

Expression of cytoskeletal and molt-related genes is temporally scheduled in the hypodermis of the crayfish Procambarus clarkii during premolt

“…Depolymerization of both actin and microtubules affects the expression of specific genes in specific cells of the retinal tissue (Oren et al, 1999). In grapevines, cytoskeleton rearrangement affects the expression of specific genes in relation to pathogen-defense mechanisms (Qiao et al, 2010). A variety of effectors of the expression of cytoskeletal genes are also well documented (e.g.…”