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Study on Vernalization-related Genes in Brassica Campestris ssp. Chinensis L.var. Utilis Tsen et Lee (Purple Flowering Stalk) and Molecular Mechanism of Its Flowering Early

Author: LiYong
Tutor: ChenGuoPing
School: Chongqing University
Course: Microbiology
Keywords: Red Kale Chinese cabbage Natural early flowering mutant FLOWERING LOCUS C (FLC) Vernalization
CLC: S634.6
Type: Master's thesis
Year: 2009
Downloads: 127
Quote: 5
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Abstract

Red Kale has extensive acreage in southern China, for nearly a thousand years of cultural history. And other brassica vegetable crops are winter annual species (such as cabbage, kale, etc.), the red moss does not require vernalization on flowering earlier. Red Kale and cabbage have similar physiological and genetic characteristics, a variant of the cabbage. But compared with the cabbage, red moss of vernalization demand but showed a huge difference. The subject of the research is based on a natural early flowering mutant physiology, molecular biology characteristics based study focusing on the key genes that control plant flowering FLC. FLC is a MADS-box transcription factor by vernalization inhibition and suppression by inhibiting the expression of related genes downstream flowering plant flowering. FLC low level of expression and function in the absence of vernalization of Arabidopsis, cabbage and other main plant early flowering. Red Kale as research material, in-depth study of the molecular mechanism of the the red moss early flowering mutant, and the vernalization gene related research. Main results are as follows: (1) Red Cabbage cloned different BrpFLC1 two cleavage products, were named as of BrpFLC1-1 and BrpFLC1-2. In BrpFLC1-1, the sixth intron is not completely cut off, resulting in the amino acids encoded BrpFLC1-1 early termination. In BrpFLC1-2, since the sixth exon is cut off, resulting BrpFLC1-2 encoding amino acid deletion of 14 amino acids. The speculated two cleavage products encoding the amino acid are not functional. (2) was cloned from the Red Cabbage Further the two FLC homologous gene, respectively the named BrpFLC2 and BrpFLC3 contains a 591 bp and a 618 bp open reading frame respectively. The coding region of BrpFLC2 BrpFLC3 the encoding 196 and 197 amino acid residues, the molecular weights were 21.91 and 21.67kD isoelectric point of 8.84 and 9.08, respectively. In the BrpFLC2, BrpFLC3 Arabidopsis AtFLC (NP ₁ 96576), respectively 84%, 82% homology. From Red Kale the FLC gene cloning and cabbage FLC has high homology. The red moss FLC compared with cabbage FLC gene, only a few nucleotide differences. (3) of the nucleotide BrpFLC2 and BrpFLC3 sequence and its encoded amino acid residue sequence bioinformatic predictions found, BrpFLC2 BrpFLC3 encoded protein has the structural characteristics of the MADS-box transcription factor, have a number of the most likely phosphorylation sites, did not find a possible O-glycosylation sites. The BrpFLC2, BrpFLC3 genes encoding proteins with Arabidopsis and cabbage FLC similar are transmembrane secondary structure prediction BrpFLC typical MADS-box protein secondary structure the, BrpFLC2, BrpFLC3 mainly localized in the nucleus as a transcriptional factors are involved in the regulation of gene expression. (4) BrpFLC gene expression patterns research, BrpFLC1, BrpFLC2, have higher levels of expression in red moss roots, stems, leaves and cotyledons. BrpFLC3 have higher levels of expression in the stems, leaves, cotyledons, lower expression in the root. The BrpFLC1, BrpFLC2 BrpFLC3 the expression suppressed by vernalization, 15 days the vernalized can BrpFLC expression have dropped to a very low level. Vernalization red moss of the vernalization the relevant gene BrpSOC1 and BrpVIN3 the elevated expression levels did not change significantly, BrpFRI. (5) Red Kale flowering time, studies have shown that red moss is a natural early flowering mutant with earlier flowering time than cabbage. The transition does not require vernalization the red moss into flowers, but the red moss the vernalization response, the vernalization treatment can shorten the time of flowering. (6) BrpFLC1 shear mode change is mainly due to early flowering red moss. Compared with late flowering cabbage, BrpFLC1 cut two transcripts function. The speculated BrpFLC1 shear a function BrpFLC1 is the main reason for early flowering red moss. Speculated FLC1 sixth intron of the first nucleotide G to A change may cause FLC1 shear disorder, leading to early flowering Red Cabbage. (7) the BrpFLC The promoter and intron I, BrpFLC2 promoter, with cabbage BrFLC2 of promoter has a similar length, sequence homology. The bioinformatics software the BrpFLC2 promoter analysis, BrpFLC2 promoter contains multiple TATA-box, CAAT-box and other cis-acting elements. The intron I BrpFLC1 and BrpFLC2 having a similar length, sequence homology with the the cabbage BrFLC1 and BrFLC2 of intron I respectively. No early flowering BrpFLC genes in these regions with red moss natural mutations related reasons. Cloned from the red moss of a region near the start codon of the FLC upstream gene the homologous gene BrpFRI the FRI in Arabidopsis mutations frequently lead to early flowering region not lead in the Red Cabbage loss of function mutations. (8) The analysis of FLC expression patterns in Red Kale and cabbage found in the red moss BrpFLC has a lower level of expression. Red Kale early flowering mutant has a certain relationship with BrpFLC lower level of expression. (9) from the Red Cabbage cloned VIN3 homologous gene BrpVIN3 period including of VIN3 the PHD and FNIII region sequences and according to the requirements of the siRNA sequence design constructed a BrpVIN3 gene RNAi vector. Laid the foundation for the production of genetically modified vegetables and brassica genus VIN3 function.

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