Abstract
Somatic embryogenesis (SE) is a
versatile model for understanding the mechanisms of plant embryogenesis and
a useful tool for plant propagation. To decipher the intricate molecular
program and potentially to control the parameters affecting the frequency of
SE, a proteomics approach based on two-dimensional gel electrophoresis (2-DE)
combined with MALDI-TOF/TOF was used. A total of 149 unique differentially
expressed proteins (DEPs) were identified at different stages of cotton SE
compared with the initial control (0 h explants). The expression profile and
functional annotation of these DEPs revealed that SE activated stress-related
proteins, including several reactive oxygen species (ROS)-scavenging enzymes.
Proteins implicated in metabolic, developmental and reproductive processes were
also identified. Further experiments were performed to confirm the role ofROS-scavenging
enzymes, suggesting the involvement of ROS homeostasis during SE
in cotton. Suppressing the expression of specifically identified GhAPX proteins
resulted in the inhibition of dedifferentiation. Accelerated redifferentiation
was observed in the suppression lines of GhAPXs or GhGSTL3, in parallel with
the alteration of endogenous ascorbate metabolism and accumulation of
endogenous H2O2 content. Moreover, disrupting endogenous redox homeostasis through
the application of high concentration of DPI, H2O2, BSO or GSH inhibited the
dedifferentiation of cotton explants. Mild oxidation induced through BSO
treatment facilitated the transition from embryogenic calluses (ECs) to somatic embryos.
Meanwhile, auxin homeostasis was altered through the perturbation of ROS homeostasis by
chemical treatments or suppression of ROS-scavenging proteins, along with
the activating/suppressing the transcription of genes related to auxin
transportation and signaling. These results show that stress responses are
activated during SE, and may regulate the ROS homeostasis by
interacting with auxin signaling.
http://www.ncbi.nlm.nih.gov/pubmed/?term=ROS%20homeostasis%20regulates%20somatic%20embryogenesis
pii: mcp.M115.049338. （IF=6.564）
PMID：27073181