Comparative Proteomic Analysis Provides New Insights into Chilling Stress Responses in Rice

Abstract

Low temperature is one of the major abiotic stresses limiting the productivity and the geographical distribution of many important crops. To gain a better understanding of chilling stress responses in rice (Oryza sativa L. cv. Nipponbare), we carried out a comparative proteomic analysis. Three-week-old rice seedlings were treated at 6°C for 6 or 24 h and then recovered for 24 h. Chilling treatment resulted in stress phenotypes of rolling leaves, increased relative electrolyte leakage, and decreased net photosynthetic rate. The temporal changes of total proteins in rice leaves were examined using two-dimensional electrophoresis. Among ϳ1,000 protein spots reproducibly detected on each gel, 31 protein spots were downregulated, and 65 were up-regulated at least at one time point. Mass spectrometry analysis allowed the identification of 85 differentially expressed proteins, including well known and novel cold-responsive proteins. Several proteins showed enhanced degradation during chilling stress, especially the photosynthetic proteins such as Rubisco large subunit of which 19 fragments were detected. The identified proteins are involved in several processes, i.e. Among various abiotic stresses, low temperature (chilling and freezing temperature) is a major stress that limits the productivity and the geographical distribution of many important crops such as rice and maize. Chilling temperatures that range from 0 to 12°C are common during the growing season in temperate regions and can substantially decrease plant productivity (1). To defend against the stress, plants use several strategies, one of which is regulation of gene expression.

A proteomic approach in analyzing heat‐responsive proteins in rice leaves

“…The down-regulation of these key enzymes shows a clear indication that carbon fixation or assimilation is highly disturbed when rice leaves are exposed to heat stress. Similar to our results, photosynthesis-related enzymes such as Rubisco, Rubisco activase, or PRK, have also been identified as down-regulated proteins in several environmental stresses, including heat treatment [5,19,41,42]. Heat-induced changes of Rubisco subunits have also been monitored in heat-sensitive and tolerant rice seedlings and it has been suggested that high temperature (over 407C), for prolonged periods (after 2 h) significantly inhibited the activity and quantity of Rubisco subunits [41].…”

“…A relative, electrolyte leakage analysis was conducted according to the protocol of Yan et al [19] with some modifications. One gram of leaf disks (1 cm diameter) were placed in 50 mL falcon tubes containing 25 mL of Milli-Q water and incubated at 287C under light for 2 h. The electrical conductivity of the bathing solution (L t ) was measured after 2 h using a conductivity meter (Model 162; Thermo Orion, MA).…”

“…In addition, cell membrane thermostability was also examined in order to evaluate the effects of heat stress on membranes. Several abiotic stresses, including heat [5] or cold [19], are able to increase the electrolyte leakage of cell membranes, which is commonly considered as an index of membrane damage or deterioration. In the present experiment, the relative electrolyte leakage of rice leaf tissues, following exposure to heat stress, increased in accordance with the time of the treatments.…”

Proteomic and metabolomic responses in hepatopancreas of Mytilus galloprovincialis challenged by Micrococcus luteus and Vibrio anguillarum

“…6). The disparity between mRNA and corresponding protein expressions was not surprising [61], since mRNA expression means the tendency of the corresponding encoded protein which does not always happen due to the posttranscriptional and posttranslational modifications [61,62].…”

Responses of Mytilus galloprovincialis to bacterial challenges by metabolomics and proteomics

“…However, the results indicated that mRNA expressions did not correlate well with the protein abundances (data not shown). The disparity between mRNA and corresponding protein expressions was not surprising [49], since mRNA expression means the tendency of the corresponding encoded protein which does not always happen due to the posttranscriptional and posttranslational modifications [49,50].…”