Proteomic and gene expression analyses during bolting-related leaf color change in Brassica rapa

Abstract

ABSTRACT. Bolting and flowering are key processes during the growth and development of Chinese cabbage (Brassica rapa L. ssp pekinensis). Understanding the molecular mechanisms underlying bolting and flowering is of significance for improving production of the vegetable. A leaf-color change from bright green to gray-green has been observed following differentiation of the flowering stem and before bolting in the vegetable, and is considered to be a signal for bolting. Proteomics in meristem tissues of an inbred line (C30) were analyzed by two-dimensional electrophoresis during the transition period. We found that some proteins were specifically expressed while others were differentially expressed. Among these, 17 proteins were specifically expressed before the color change, 18 were specifically expressed after the color change, 21 were downregulated during the color change, and 29 were upregulated. Mass spectrometric analysis (MALDI-TOF-TOF/MS) was used to analyze 17 protein spots, and four proteins (subunit E1 of vacuolar-type H + transporter ATPase, the large subunit of Rubicon, S-adenosylmethionine synthetase, and tubulin α-2) were identified. qPCR analysis was conducted to quantify the expression of genes encoding these proteins during the transitional period. The expression of BrVHA-E1, BrSAMS, BrrbcL, and BrTUA6 was significantly different before and after the leaf-color change, suggesting that these genes might be involved in regulating flower differentiation and bolting.

Quantitative Proteomics Analysis of Lettuce (Lactuca sativa L.) Reveals Molecular Basis-Associated Auxin and Photosynthesis with Bolting Induced by High Temperature

“…It was found that sugar beet contains a large CONSTANS -like gene family, independent of the early-bolting ( B ) gene locus [ 5 ]. It was also speculated that the BrVHA-E1 , BrSAMS , BrrbcL , and BrTUA6 genes might be involved in regulating the flower differentiation and bolting of Brassica rapa according to their significantly different expression levels [ 6 ]. S-adenosylmethionine synthetase (SAMS) is a precursor of ethylene [ 7 ].…”

“…Research by Strompen et al shows that VHA-E1 is involved in regulating early embryogenesis in Arabidopsis [ 9 ]. Zhang et al speculated that BrVHA-E1 is only associated with the differentiation of flower buds [ 6 ]. Microtubules exist widely in the cytoskeleton, and are important for cellular morphology, cell division, transportation, energy transfer, and signal transduction, and α-tubulin ( TUA ) is the basic unit of microtubules.…”

“…BrrbcL was up-regulated after color change. It boosts the synthesis of photosynthetic products, leading to an increased C/N ratio, and the subsequent occurrence of bolting and flowering in the plant [ 6 ]. ZCE1 is a cis-cinnamic acid ( Zusammen - cinnamic acid )- Enhanced gene, which encodes a member of the major latex protein-like ( MLPL ) gene family.…”