Environmental stress alters genes expression and induces ovule abortion: reactive oxygen species appear as ovules commit to abort

Abstract

Environmental stress dramatically reduces plant reproduction. Previous results showed that placing roots in 200 mM NaCl for 12 h caused 90% of the developing Arabidopsis ovules to abort (Sun et al. in Plant Physiol 135:2358-2367, 2004). To discover the molecular responses that occur during ovule abortion, gene expression was monitored using Affymetrix 24k genome arrays. Transcript levels were measured in pistils that were stressed for 6, 12, 18, and 24 h, then compared with the levels in healthy pistils. Over the course of this experiment, a total of 535 salt-responsive genes were identified. Cluster analysis showed that differentially expressed genes exhibited reproducible changes in expression. The expression of 65 transcription factors, some of which are known to be involved in stress responses, were modulated during ovule abortion. In flowers, salt stress led to a 30-fold increase in Na+ ions and modest, but significant, decreases in the accumulation of other ions. The expression of cation exchangers and ion transporters were induced, presumably to reestablish ion homeostasis following salt stress. Genes that encode enzymes that detoxify reactive oxygen species (ROS), including ascorbate peroxidase and peroxidase, were downregulated after ovules committed to abort. These changes in gene expression coincided with the synthesis of ROS in female gametophytes. One day after salt stress, ROS spread from the gametophytes to the maternal chalaza and integuments. In addition, genes encoding proteins that regulate ethylene responses, including ethylene biosynthesis, ethylene signal transduction and ethylene-responsive transcription factors, were upregulated after stress. Hypotheses are proposed on the basis of this expression analysis, which will be evaluated further in future experiments.

Comparative proteomic analysis of longan (Dimocarpus longan Lour.) seed abortion

“…Some researchers showed that a change in cAPX activity is an early event in the PCD process, with a 50% decrease in activity occurring immediately after induction of PCD (Vacca et al 2004;Locato et al 2009). It was also reported that APX genes are down-regulated after ovules commit to abortion (Sun et al 2005). In our study, three protein spots (i.e., spot nos.…”

Flower Development under Drought Stress: Morphological and Transcriptomic Analyses Reveal Acute Responses and Long-Term Acclimation in Arabidopsis

“…Furthermore, Arabidopsis exhibits female reproductive organ abortion because of salt stress (Park et al, 2004;Sun et al, 2004). Another study uncovered altered expression of genes encoding 65 transcription factors in response to salt stress, including 6 ETHYLENE RESPONSE FACTOR (ERF)/AP2-family members and 11 NAC proteins (Sun et al, 2005). However, these studies did not characterize reproductive development.…”

The Silver Lining of a Viral Agent: Increasing Seed Yield and Harvest Index in Arabidopsis by Ectopic Expression of the Potato Leaf Roll Virus Movement Protein

“…4B). Thus, we assume that improved resource allocation during seed set and development might have reduced the frequency of ovule abortion, a process that frequently occurs during reproduction, in particular in response to nutrient limitations and environmental stress (Sun et al, 2004(Sun et al, , 2005.…”