Remodelling of lace plant leaves: antioxidants and ROS are key regulators of programmed cell death

Abstract

Main conclusion Antioxidants and reactive oxygen species are integral for programmed cell death signaling during perforation formation in the lace plant ( Aponogeton madagascariensis ). The lace plant is an excellent model system for studying developmentally regulated programmed cell death (PCD). During early lace plant leaf development, PCD systematically deletes cells resulting in a perforated leaf morphology that is unique in planta. A distinct feature in young lace plant leaves is an abundance of anthocyanins, which have antioxidant properties. The first sign of PCD induction is the loss of anthocyanin pigmentation in cells that are targeted for destruction, which results in a visible gradient of cell death. The cellular dynamics and time course of lace plant PCD are well documented; however, the signals involved in the pathway remain elusive. This study investigates the roles of antioxidants and ROS in developmental PCD signaling during lace plant perforation formation. The involvement of antioxidants and ROS in the pathway was determined using a variety of techniques including pharmacological whole plant experimentation, long-term live cell imaging, the 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid anti-radical activity assay, and western blot analysis. Results indicate that antioxidants and ROS are key regulators of PCD during the remodelling of lace plant leaves.Electronic supplementary materialThe online version of this article (doi:10.1007/s00425-017-2683-y) contains supplementary material, which is available to authorized users.

The role of auxin in developmentally regulated programmed cell death in lace plant

“…The anthocyanin extraction protocol was similar to the techniques described by Dauphinee et al. (), adapted from that of Li et al. ().…”

“…Window‐stage leaves were histochemically stained to detect superoxides (a type of ROS) in accordance with the method of Dauphinee et al. (), modified from that of Grellet Bournonville and Díaz‐Ricci (). Leaves from control and NPA‐treated plants were cut into 5 mm 2 sections and submerged in nitro blue tetrazolium (NBT) stain consisting of 50 mM potassium phosphate buffer (pH 7.8), 10 mM sodium azide, and 0.1% NBT (Sigma‐Aldrich).…”

“…Sample preparation for SDS‐PAGE and western blotting were done as described by Dauphinee et al. (). The nitrocellulose membrane was stained with Ponceau (0.5% w/v Ponceau S, 1% v/v acetic acid) for 5 min with mild shaking, and then rinsed for 2 min in TBS‐T (Tris‐buffered saline with Tween 20: 0.1% v/v Tween 20, 50 mM Tris‐HCl, 150 mM NaCl).…”

“…Pre‐perforation‐stage leaves emerge from the corm tightly furled, and vascular tissue formation and vein patterning are nearly complete. The cells of pre‐perforated leaves contain a pink pigmentation due to the abundance of anthocyanin, a powerful antioxidant (Gunawardena et al., ; Dauphinee et al., ). Light and scanning electron microscopy observations provide no morphological indications that PCD is occurring in pre‐perforated leaves (Gunawardena et al., ).…”

Chemical Defoliant Promotes Leaf Abscission by Altering ROS Metabolism and Photosynthetic Efficiency in Gossypium hirsutum

“…ROS play an important role in plant growth and development, especially in stress tolerance [38]. In plants, ROS regulate many developmental processes such as cell proliferation and differentiation, seed germination, programmed cell death, senescence [39][40][41][42][43]. ROS include H 2 O 2 , O 2− , singlet oxygen, and the hydroxyl radical [13,44].…”