Caffeine-Induced Premature Chromosome Condensation Results in the Apoptosis-Like Programmed Cell Death in Root Meristems of Vicia faba

Abstract

We have demonstrated that the activation of apoptosis-like programmed cell death (AL-PCD) was a secondary result of caffeine (CF) induced premature chromosome condensation (PCC) in hydroxyurea-synchronized Vicia faba root meristem cells. Initiation of the apoptotic-like cell degradation pathway seemed to be the result of DNA damage generated by treatment with hydroxyurea (HU) [double-stranded breaks (DSBs) mostly] and co-treatment with HU/CF [single-stranded breaks (SSBs) mainly]. A single chromosome comet assay was successfully used to study different types of DNA damage (neutral variant–DSBs versus alkaline–DSBs or SSBs). The immunocytochemical detection of H2AXS139Ph and PARP-2 were used as markers for DSBs and SSBs, respectively. Acridine orange and ethidium bromide (AO/EB) were applied for quantitative immunofluorescence measurements of dead, dying and living cells. Apoptotic-type DNA fragmentation and positive TUNEL reaction finally proved that CF triggers AL-PCD in stressed V. faba root meristem cells. In addition, the results obtained under transmission electron microscopy (TEM) further revealed apoptotic-like features at the ultrastructural level of PCC-type cells: (i) extensive vacuolization; (ii) abnormal chromatin condensation, its marginalization and concomitant degradation; (iii) formation of autophagy-like vesicles (iv) protoplast shrinkage (v) fragmentation of cell nuclei and (vi) extensive degeneration of the cells. The results obtained have been discussed with respect to the vacuolar/autolytic type of plant-specific AL-PCD.

Influence of Exogenously Supplemented Caffeine on Cell Division, Germination, and Growth of Economically Important Plants

“…Vicia faba [21]. Interestingly, Friedman and Waller [22] reported repression of mitosis and cell plate formation in coffee seeds exposed to 10 mM caffeine, while Valster and Hepler [23] observed that caffeine allows initiation of the cell plate formation but prevents its completion in living Tradescantia stamen hair cells.…”

Normal and Abortive Buds Transcriptomic Profiling of Broccoli ogu Cytoplasmic Male Sterile Line and Its Maintainer

“…Programmed cell death (PCD) is an important physiological process in single cells and penetrates the whole plant life cycle, which can help plants to control and organize the destruction of non-functional or redundant damaged cells [ 13 , 14 , 15 ]. Although PCD is a natural result of ageing, it may be switched on by environmental stress or irregular development in plants [ 15 ]. Increases in caspase-like proteases [ 16 ] and ROS [ 17 , 18 ] activities of metacaspase gene family related genes [ 19 ] are the important features of PCD.…”

The Relationship between Terminal Bud Death and Programmed Cell Death in Paulownia spp.

“…The apoptosis was first observed in the epidermal cells and later in the cotyledons and hypocotyls [28]. The results obtained under transmission electron microscopy (TEM) further revealed apoptotic-like features at the ultrastructural level of PCD-type cells: extensive vacuolization, abnormal chromatin condensation, its marginalization and concomitant degradation, formation of autophagylike vesicles, protoplast shrinkage, fragmentation of cell nuclei, and extensive degeneration of the cells [29]. Wang found that heat stress induced PCD in maize seedling leaves, which was characterized by chromatin DNA laddering and DNA strand breaks detected by a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) test [30].…”

“…DAPI staining was performed according to [7]. Terminal bud DNA was extracted by the CTAB method [8].…”