Proteomics of heat-stress and ethylene-mediated thermotolerance mechanisms in tomato pollen grains

Sridharan Jegadeesan, Palak Chaturvedi, Arindam Ghatak, Etan Pressman, Shimon Meir, Adi Faigenboim, Nicholas Rutley, Avital Beery, Arye Harel, Wolfram Weckwerth, Nurit Firon

Heat stress is a major cause for yield loss in many crops, including vegetable crops. Even short waves of high temperature, becoming more frequent during recent years, can be detrimental. Pollen development is most heat-sensitive, being the main cause for reduced productivity under heat-stress across a wide range of crops. The molecular mechanisms involved in pollen heat-stress response and thermotolerance are however, not fully understood. Recently, we have demonstrated that ethylene, a gaseous plant hormone, plays a role in tomato (Solanum lycopersicum) pollen thermotolerance. These results were substantiated in the current work showing that increasing ethylene levels by using an ethylene-releasing substance, ethephon, prior to heat-stress exposure, increased pollen quality. A proteomic approach was undertaken, to unravel the mechanisms underlying pollen heat-stress response and ethylene-mediated pollen thermotolerance in developing pollen grains. Proteins were extracted and analyzed by means of a gel LC-MS fractionation protocol, and a total of 1,355 proteins were identified. A dataset of 721 proteins, detected in three biological replicates of at least one of the applied treatments, was used for all analyses. Quantitative analysis was performed based on peptide count. The analysis revealed that heat-stress affected the developmental program of pollen, including protein homeostasis (components of the translational and degradation machinery), carbohydrate, and energy metabolism. Ethephon-pre-treatment shifted the heat-stressed pollen proteome closer to the proteome under non-stressful conditions, namely, by showing higher abundance of proteins involved in protein synthesis, degradation, tricarboxylic acid cycle, and RNA regulation. Furthermore, up-regulation of protective mechanisms against oxidative stress was observed following ethephon-treatment (including higher abundance of glutathione-disulfide reductase, glutaredoxin, and protein disulfide isomerase). Taken together, the findings identified systemic and fundamental components of pollen thermotolerance, and serve as a valuable quantitative protein database for further research.

Research Platform Vienna Metabolomics Center, Large-Instrument Facility for Mass Spectrometry in Life Sciences
External organisation(s)
Agricultural Research Organization of Israel, Hebrew University Jerusalem
Frontiers in Plant Science
Publication date
Peer reviewed
Austrian Fields of Science 2012
106037 Proteomics, 106044 Systems biology, 106002 Biochemistry
ASJC Scopus subject areas
Control and Systems Engineering, Computer Science(all)
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