The Life and Death of a Plant Cell

Abstract

Like all eukaryotic organisms, plants possess an innate program for controlled cellular demise termed programmed cell death (PCD). Despite the functional conservation of PCD across broad evolutionary distances, an understanding of the molecular machinery underpinning this fundamental program in plants remains largely elusive. As in mammalian PCD, the regulation of plant PCD is critical to development, homeostasis, and proper responses to stress. Evidence is emerging that autophagy is key to the regulation of PCD in plants and that it can dictate the outcomes of PCD execution under various scenarios. Here, we provide a broad and comparative overview of PCD processes in plants, with an emphasis on stress-induced PCD. We also discuss the implications of the paradox that is functional conservation of apoptotic hallmarks in plants in the absence of core mammalian apoptosis regulators, what that means, and whether an equivalent form of death occurs in plants.

Subtilisin‐like proteases in plant defence: the past, the present and beyond

“…This specific group of subtilases can be divided into two subgroups, saspases and phytaspases, that are distinguished by their substrate specificity and role in PCD [reviewed in Kabbage et al . () and Vartapetian et al . ()].…”

“…Considering their caspase specificity, phytaspases have preference for peptide recognition patterns such as VEID, IETD, LEHD and VDVAD [reviewed in Kabbage et al . () and Vartapetian et al . ()].…”

“…These proteases, displaying amino acid sequence similarity to subtilases and containing an active-site Ser residue, exhibit caspase specificity Coffeen and Wolpert, 2004). This specific group of subtilases can be divided into two subgroups, saspases and phytaspases, that are distinguished by their substrate specificity and role in PCD [reviewed in Kabbage et al (2017) and Vartapetian et al (2011)]. Saspases are extracellular proteins responsible for RuBisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) proteolysis in PCD, and prefer the peptide recognition pattern of caspases, such as IETD and LEHD.…”

Sorghum stem aerenchyma formation is regulated by SbNAC_D during internode development

“…Programmed cell death plays an important role in plant development in response to pathogens and abiotic stress (Kabbage, Kessens, Bartholomay, & Williams, ; Van Hautegem, Waters, Goodrich, & Nowack, ). The accumulation of aerenchyma in stem pith parenchyma cells provides a way to remobilize nutrients from these cells to support rapid growth of stems and leaves during the vegetative phase.…”

Vacuolar processing enzyme activates programmed cell death in the apical meristem inducing loss of apical dominance

“…We previously proposed that programmed cell death (PCD) in the tuber apical meristem (TAM) is one of the mechanisms regulating AD (Teper‐Bamnolker et al, ). PCD plays an important role in various stages of plant development, such as embryogenesis, self‐incompatibility, xylogenesis, and senescence, and in the response to biotic or abiotic stresses (Gunawardena & McCabe, ; Kabbage, Kessens, Bartholomay, & Williams, ; Van Hautegem, Waters, Goodrich, & Nowack, ). Hallmarks of PCD identified in the TAM during normal growth were more extensive when AD was lost following either extended cold storage or BE treatment (Eshel & Teper‐Bamnolker, ).…”