Proteomic identification of differentially expressed proteins in the anoxic rice coleoptile

Abstract

Rice is the staple food for more than fifty percent of the world's population, and is therefore an important crop. However, its production is hindered by several biotic and abiotic stresses. Although rice is the only crop that can germinate even in the complete absence of oxygen (i.e. anoxia), flooding (low oxygen) is one of the major causes of reduced rice production. Rice germination under anoxia is characterized by the elongation of the coleoptile, but leaf growth is hampered. In this work, a comparative proteomic approach was used to detect and identify differentially expressed proteins in the anoxic rice coleoptile compared to the aerobic coleoptile. Thirty-one spots were successfully identified by MALDI-TOF MS analysis. The majority of the identified proteins were related to stress responses and redox metabolism. The expression levels of twenty-three proteins and their respective mRNAs were analyzed in a time course experiment.

Tolerance of anaerobic conditions caused by flooding during germination and early growth in rice (Oryza sativa L.)

“…The action of tubulin a-1 chain (TUBA1) and actin depolymerizing factor 4 (ADF4) were suggested to be involved in fast coleoptile elongation under anaerobic conditions, as both genes are upregulated under anoxia during germination in rice (Sadiq et al, 2011). Tubulins are involved in the formation of microtubules and are important for both cell division and elongation, and ADF4 is involved in regulating actin assembly (Mayer and Jürgens, 2002; Augustine et al, 2008; Sadiq et al, 2011); therefore both are speculated to play a role in fast growth of the coleoptiles under low oxygen. However, further studies are required to ascertain the actual roles of these genes in coleoptile growth and tolerance of hypoxia or anoxia.…”

Examination of the leaf proteome during flooding stress and the induction of programmed cell death in maize

“…While proteomic approaches have been effective in characterizing protein expression patterns during stress responses [11], only a few proteomic studies have examined flooding or anoxia stresses in plants, which include tomato [11], rice [12], soybean [13], wheat [14] and maize [15]. Previous studies have indicated that an early rise in cytosolic Ca 2+ , an establishment of ionic homeostasis and root tip death may be essential adaptive changes enabling flood tolerance in maize [16].…”

Water submersion of seeds from three bean cultivars

“…In 25-day-old Vigna, hypoxia induced an increase in the SOD activity, the APX and the GSR in tolerant genotypes (Sairam et al, 2011). In rice coleoptiles under aerobic or anaerobic conditions, the ROS-scavenging enzymes GST, APX cytosolic and putative GST were inhibited (Sadiq et al, 2011), and this response was interpreted as a form of signalling in response to the increasing ROS concentration in anoxic environments (Fukao & Bailey-Serres, 2004). In soybean under hypoxic conditions, there was also a reduction in the APX activity (Shi et al, 2008;Hashiguchi et al, 2009).…”

“…Hypoxia over a period of eight days increased the activities of the ROS-scavenging enzymes superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GSR) activities in tolerant genotypes of 25-day-old Vigna, suggesting the removal of excess ROS associated with flooding stress (Sairam et al, 2011). Furthermore, the ROS-scavenger enzymes glutathione-S-transferase (GST), cytosolic APX and a putative GST were inhibited in rice coleoptiles under anaerobic conditions (Sadiq et al, 2011). Similar results have been reported with APX for soybean under hypoxic conditions (Hashiguchi et al, 2009;Shi et al, 2008).…”

“…Anoxia has been related to protein synthesis inhibition, decrease in the ADH activity in the availability of ATP (Kato-Noguchi, 2001), the activation of pyruvate dehydrogenase, HSPs (heat shock proteins), CBl5 (calcineurin B-like-protein) and USP (universal stress protein) (Sadiq et al, 2011) and further increases in antioxidant enzyme activity during and after the stress release caused by flooding (Sairam et al, 2011). Therefore, biochemical components were analysed in the bean seeds and examined in relation to their performance under submersion.…”