Production and Scavenging of Reactive Oxygen Species and Redox Signaling during Leaf and Flower Senescence: Similar But Different

Abstract

ORCID IDs: 0000-0003-3830-5857 (H.R.); 0000-0001-6523-6848 (S.M.-B.).Reactive oxygen species (ROS) play a key role in the regulation of many developmental processes, including senescence, and in plant responses to biotic and abiotic stresses. Several mechanisms of ROS generation and scavenging are similar, but others differ between senescing leaves and petals, despite these organs sharing a common evolutionary origin. Photosynthesis-derived ROS, nutrient remobilization, and reversibility of senescence are necessarily distinct features of the progression of senescence in the two organs. Furthermore, recent studies have revealed specific redox signaling processes that act in concert with phytohormones and transcription factors to regulate senescence-associated genes in leaves and petals. Here, we review some of the recent advances in our understanding of the mechanisms underpinning the production and elimination of ROS in these two organs. We focus on unveiling common and differential aspects of redox signaling in leaf and petal senescence, with the aim of linking physiological, biochemical, and molecular processes. We conclude that the spatiotemporal impact of ROS in senescing tissues differs between leaves and flowers, mainly due to the specific functionalities of these organs.

Singlet Oxygen Plays an Essential Role in the Root’s Response to Osmotic Stress

“…PCD is one means by which plants can remobilize essential nutrients to benefit surviving tissue (Munne-Bosch and Alegre, 2004;Rogers and Munné-Bosch, 2016). In the root tip, PCD can be viewed as an adaptive mechanism promoting lateral root development (Huh et al, 2002;Ji et al, 2014).…”

Photo-Oxidative Stress during Leaf, Flower and Fruit Development

“…Excessive levels of light in chloroplasts, caused by drought, salinity, extreme temperatures, high levels of light, or a combination of these factors, lead to photoinhibition and photooxidative stress, thus potentially causing photoinhibitory damage to the photosynthetic apparatus (Box 1). Although it is generally assumed that mitochondria, peroxisomes, and the apoplast are the main sources of ROS in flowers and fruits (Qin et al, 2009b;Rogers and Munné-Bosch, 2016), flower corollas and fruit exocarps in several species also accumulate excessive levels of light during the early developmental stages, generally until organ maturation is reached. Thus, photoinhibition and photooxidative stress also can occur in these organs (Arrom and Munné-Bosch, 2010;Hengari et al, 2014;Naschitz et al, 2015;Gang et al, 2016).…”

“…Here, we aim to go beyond our previous comparative analysis of ROS production and elimination in leaves and flowers (Rogers and Munné-Bosch, 2016) by providing a new conceptual framework for chloroplasts as central players in redox signaling in leaf, flower, and fruit development. This review will discuss recent advances in our understanding of photooxidative stress and redox signaling in leaves, flowers, and fruits, focusing on key spatiotemporal processes that determine specific responses in each organ.…”

Recent Progress in Understanding the Role of Reactive Oxygen Species in Plant Cell Signaling

“…Our most detailed knowledge of ROS functions still comes from work with photosynthesizing leaves; therefore, the majority of reports in this special issue focus on leaf processes. Other contributions address ROS-dependent regulation of flower senescence (Rogers and Munné-Bosch, 2016), polar growth of pollen and root hairs (Mangano et al, 2016), and other root processes, including root architecture formation (Evans et al, 2016;Liu et al, 2016).…”