Mitochondrial Biogenesis in Diverse Cauliflower

The early generative phase of cauliflower (Brassica oleracea var. botrytis) curd ripening is 21 sensitive to the water deficit. Mitochondrial responses under drought within Brassica genus are 22 poorly understood. The main goal of this study was to investigate the mitochondrial biogenesis of 23 three cauliflower cultivars varying with drought tolerance. Diverse quantitative changes 24 (down-regulations mostly) in the mitochondrial proteome were assayed by 2D PAGE coupled with 25 LC-MS/MS. Respiratory (e.g. CII, CIV and ATP synthase subunits), transporter (including diverse 26 porin isoforms) and matrix multifunctional proteins (e.g. components of RNA editing machinery) 27 appeared diversely affected in their abundance under two drought levels. Western immunoassays 28 showed also cultivar-specific responses of selected mitochondrial proteins. Dehydrin-related 29 tryptic peptides found in few 2D spots that appeared immunopositive with dehydrin-specific 30 antisera highlighted the relevance of mitochondrial dehydrin-like proteins for the drought 31 response. The level of selected messengers participating in drought response was also determined. 32 We conclude that the mitochondrial biogenesis was strongly, but diversely affected in various 33 cauliflower cultivars and associated with drought tolerance on the proteomic and functional levels. 34 However, transcriptomic and proteomic regulations were largely uncoordinated due to the 35 suggested altered availability of messengers for translation, mRNA/ribosome interactions and/or 36 miRNA impact on transcript abundance and translation. 37