Metabolism of reactive oxygen species in cotton cytoplasmic male sterility and its restoration

Abstract

To elucidate reactive oxygen species (ROS) metabolism of cotton cytoplasmic male sterility and the effects of restorer gene on the metabolism of ROS, the metabolism changes in the production and scavenging of ROS and gene expression related to ROS-scavenging enzymes were investigated in the anther mitochondria of CMS line, maintainer line and hybrid F(1). During the abortion preliminary stage (sporogenous cell division stage), anthers of CMS line had a little higher superoxide (O(2)(-)) production rate and hydrogen peroxide (H(2)O(2)) and malondialdehyde (MDA) contents than those of maintainer or hybrid F(1. )Simultaneously, a little higher ROS contents might serve as a signal to increase the activity of superoxide dismutase (SOD) in anthers of CMS line to reduce the ROS damage to the anther development. But at the abortion peak (pollen mother cell meiosis stage), anthers of CMS line had extraordinarily higher ROS contents and lower ROS-scavenging enzymic activities compared with the hybrid F(1), during which the ROS contents and ROS-scavenging enzymic activities in hybrid F(1) were approximate to those of maintainer line. The expression of Mn-sod and apx mRNA in anther of CMS line was obviously inhibited when ROS produced with a great deal during anther abortion, however the gene expression in hybrid F(1) kept normal with the maintainer. Excessive accumulation of O(2)(*-) , H(2)O(2 )and MDA, significant reduction of ROS-scavenging enzymic activities and lower gene expression level of ROS-scavenging enzyme were coinstantaneous with male cells death in anthers of CMS line. But when the restorer gene was transferred into CMS line, excessive production of ROS could be eliminated in the anthers of hybrid F(1). The restorer gene likely plays an important role in keeping the dynamic balance between the production and elimination of ROS.

The Cell Death in CMS Plants

“…Microsporogenesis in restored maize CMS-T (A239 Rf) plants is quite different from the male sterile plants, while it is not significantly different from that in normal plants [20]. Similar PCD pathways are blocked by matching nuclear restorer genes in cotton cytoplasmic male sterility and maize CMS-S [21], [22].…”

“…The generation rate of ROS, e.g. O2-, H 2 O 2 , in sterile line is higher than that in maintainer line [21], [26], [32].…”

“…The decrease of L-ascorbic acid attenuates the activities of APX, GR, DHAR, MDHAR and GSH. Therefore, the expression of APX, GR, DHAR, MDHAR and SOD are down-regulated during the development of microspores in CMS line [21], [32].…”

“…In order to repress mitochondrial cell-death signaling pathways in all except anthers, regulators of ROS-mediated signaling triggered cell death [5]. Numerous studies suggested that pollen abortion of the sterile plants is associated with PCD, such as PET1-CMS in sunflower, Honglian (HL)-CMS line of rice, cotton cytoplasmic male sterility, CMS-T and CMS-S of maize [15], [16], [21], [22], [26]. Most PCD is related with excessive production of ROS and lower ROS-scavenging enzymic activities in CMS plants at the abortion peak.…”

THE RELATIONSHIP BETWEEN MALE STERILITY AND MEMBRANE LIPID PEROXIDATION AND ANTIOXIDANT ENZYMES IN WHEAT (Triticum aestivum L.)

“…In the process of plant growth and development, antioxidant enzymes play an important role not only in the biochemical signs but also in male sterility (Deng et al, 2012;Jiang et al, 2007). Reactive oxygen species (ROS) is a by-product in the process of aerobic metabolism.…”