Comparative proteomic analysis of cauliflower under high temperature and flooding stresses

- Cauliflower cultivars H41 and H69 are tolerant to high temperature and flooding, respectively.
- Physiological and proteomic responses of cauliflower genotypes to flood stress at 40 °C were determined.
- Comparative proteomic analysis identified 85 protein peaks during different time periods in all genotypes.
- Differentially regulated proteins predominantly functioned in photosynthesis and metabolism.

High-temperature and waterlogging are major abiotic stresses that affect the yield and quality of cauliflower. Cauliflower cultivars 'H41' and 'H69' are tolerant to high temperature and flooding, respectively; however, 'H71' is sensitive to both stresses. The objectives of this study were to identify the proteins that were differentially regulated and the physiological changes that occurred during different time periods in 'H41', 'H69', and 'H71' when responding to treatments of flooding, 40 °C, and both stresses combined. Changes in the leaf proteome were analyzed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and identified by Mascot peptide mass fingerprint (PMF) and database searching. Stress treatments caused significant reductions in electrolyte leakage, chlorophyll fluorescence Fv/Fm, chlorophyll content, and water potential as stress times were prolonged. By the comparative proteomic analysis, 85 protein peaks that were differentially expressed in response to combination treatments at 0, 6, and 24 h, 69 (33 in 'H41', 29 in 'H69', and 9 in 'H71') were identified, of which were cultivar specific. Differentially regulated proteins predominantly functioned in photosynthesis and to a lesser extent in energy metabolism, cellular homeostasis, transcription and translation, signal transduction, and protein biosynthesis. This is the first report that utilizes proteomics to discover changes in the protein expression profile of cauliflower in response to heat and flooding.

Identified protein peaks (231, 232, 241, 251, 252, and 253) of cauliflower 'H41' plants by the ProteomeLab PF-2D Protein Fractionation System (Beckman Coulter) in comparing FH and NFC at 24 h.