Reactive Oxygen Species as Mediators of Gametophyte Development and Double Fertilization in Flowering Plants

Abstract

Reactive oxygen species (ROS) are toxic by-products of aerobic metabolism. In plants, they also function as important signaling molecules that regulate biotic and abiotic stress responses as well as plant growth and development. Recent studies have implicated ROS in various aspects of plant reproduction. In male gametophytes, ROS are associated with germline development as well as the developmentally associated programmed cell death of tapetal cells necessary for microspore development. ROS have a role in regulation of female gametophyte patterning and maintenance of embryo sac polarity. During pollination, ROS play roles in the generation of self-incompatibility response during pollen-pistil interaction, pollen tube growth, pollen tube burst for sperm release and fertilization. In this mini review, we provide an overview of ROS production and signaling in the context of plant reproductive development, from female and male gametophyte development to fertilization.

cROStalk for Life: Uncovering ROS Signaling in Plants and Animal Systems, from Gametogenesis to Early Embryonic Development

“…The role of mitochondrial ROS for proper embryo sac development in female gametophyte development has been demonstrated in several works. This link has been shown in multiple Arabidopsis mutants and excellent reviews are available [ 214 ]. Interestingly, a potential role of oxidative stress in the balance between sexual megasporogenesis and apomixis program in facultative apomictic plants also has been proposed recently [ 215 , 216 ].…”

“…Referring to the pollen–pistil interaction, it has been suggested that the ROS signals originating at the pollen grains mediate the interaction with the stigma by controlling the expression of the inward shaker K + channel SPIK in pollen [ 227 ]. Pollen–stigma signaling is involved in the different mechanisms of self-incompatibility in multiple plant species [ 214 , 228 ]. ROS regulation is important for the control of self-incompatibility processes in plants, as reported in many species, although specific strategies might differ between plant systems and developmental stages, including defense functions, signaling, and senescence [ 229 ].…”

“…The decreased ROS levels in kale stigma exposed to exogenous flavonoid treatment had a negative impact on the attachment and successive germination of the compatible pollen. In recent years, multiple works have investigated ROS signaling in pollen–stigma communication—we apologize for not discussing them because of space limitations [ 212 , 214 , 229 , 231 ].…”

ROS and Ions in Cell Signaling during Sexual Plant Reproduction

“…Endogenous mechanisms maintaining the polar growth are conveniently studied in vitro, but female sporophyte tissues produce a number of their own molecules that can influence tube growth by enhancing, directing, or blocking it. In particular, the direction of tube growth can be affected by [Ca 2+ ], NO, and ROS in pistil tissues, and the latter can both support growth and stop it if fertilization is undesirable [ 7 , 50 , 51 ].…”

“…Signals that determine pollen tube growth direction include sporophyte-derived ROS, NO, polyamines, and peptides [ 6 , 77 , 78 ]; in many of these cases, ROS are also involved in signal perception [ 50 ].…”