Evidence for programmed cell death and activation of specific caspase-like enzymes in the tomato fruit heat stress response

Abstract

The tomato (Lycopersicon esculentum) fruit is the best available model to study the stress response of fleshy fruit. Programmed cell death (PCD) plays an important role in stress responses in mammals and plants. In this study, we provide evidence that PCD is triggered in the tomato fruit heat stress response by detection of the sequential diagnostic PCD events, including release of cytochrome c, activation of caspase-like proteases and the presence of TUNEL-positive nuclei. Investigating the time course of these events for 12 h after heat treatment indicated that cytochrome c release and caspase-like protease activation occurred rapidly and were consistent with the onset of DNA fragmentation. In addition, LEHDase and DEVDase enzymes were specifically activated in tomato fruit pericarp during the heat treatment and recovery time. There was no significant activation of YVADase or IETDase proteases. Preincubation of pericarp discs with the broad-spectrum, cell-permeable caspase inhibitor Z-VAD-FMK, suppressed heat-induced cell death measured by trypan blue, accompanied by a decrease in LEHDase and DEVDase activities.

Cell wall metabolism and chilling injury during postharvest cold storage in zucchini fruit

“…The electrolyte leakage was expressed as percentage of total conductivity. Cell death assay was carried out by estimation of trypan blue uptake according to Qu et al (2009) with some modifications. Exocarp was separated with a vegetable peeler and 5 discs were taken from each replicate with an 11 mm diameter stainless-steel cork borer.…”

Lupine embryo axes under salinity stress. I. Ultrastructural response

“…Plant PCD was observed under the influence of abiotic stress factors such as heat shock (Qu et al 2009), cold stress (Koukalová et al 1997), micronutrient deficiency (Koshiba et al 2008), or heavy metals, mainly cadmium Cd 2? treatment (Ma et al 2010).…”

Plantation Forestry under Global Warming: Hybrid Poplars with Improved Thermotolerance Provide New Insights on the in Vivo Function of Small Heat Shock Protein Chaperones

“…To protect cell function, plants have evolved a complex metabolic adjustment process known as the heat shock response (HSR; Kotak et al, 2007;Mittler at al., 2012). Alternatively, programmed cell death is activated in specific cells, resulting in leaf shedding or abortion of reproductive organs (Qu et al, 2009;Blanvillain et al, 2011). Whereas research in forest trees remains scarce, the ubiquitous and conserved HSR has been thoroughly studied in herbaceous plants (Larkindale and Vierling, 2008;Hu et al, 2009;Finka et al, 2011;Mittler et al, 2012).…”