Flowering time is a very important agronomic trait in Brassica crops and regulation of the time is one of major factor in the breeding program. To understand the control of flowering time in Brassica rapa, we have carried out Br300K microarray with two contrasting Brassica inbred lines, Rapid Cycling B. rapa (RCBr) as rapid cycling type and B. rapa ssp. pekinensis inbred line Chiifu as slow flowering phenotype. Reproductive process-related genes were specifically expressed in RCBr, whereas environmental stimuli-responsive genes in Chiifu. Flowering stimulating genes, such as BrFT and BrSOC1, were preferentially expressed in RCBr, while flowering repressing genes, such as BrFLC and BrMAF4, expressed in Chiifu. Several paralogues present in B. rapa, BrFLCs and BrCOLs, were expressed with paralog-specific pattern depending on flowering phenotypes: i.e., BrFLC1 and BrFLC2, major floral repressors, were expressed in Chiifu, BrFLCL/BrFLC5 in RCBr and BrFLC3 in both plants. The expression of several flowering repressing genes was gradually decreased in RCBr growth, but increased in Chiifu growth. However, the expression of genes involved in photoperiodic flowering was no difference between these two plants under LD and SD conditions, indicating photoperiodic pathway is not major factor to distinguish fast vs. slow flowering in B. rapa. The mechanism underlined in the rapid or fast flowering of RCBr would be further elucidated in association with the controlling mechanism of its short life span.

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• Homeologs of Brassica SOC1, a central regulator of flowering time, are differentially regulated due to partitioning of evolutionarily conserved transcription factor binding sites in promoters
  Tanu Sri, Bharat Gupta, Shikha Tyagi, Anandita Singh
  Molecular Phylogenetics and Evolution.2020; 147: 106777.     CrossRef
• Genome-wide analysis of spatiotemporal gene expression patterns during floral organ development in Brassica rapa
  Soo In Lee, Muthusamy Muthusamy, Muhammad Amjad Nawaz, Joon Ki Hong, Myung-Ho Lim, Jin A. Kim, Mi-Jeong Jeong
  Molecular Genetics and Genomics.2019; 294(6): 1403.     CrossRef
• Genome-wide identification of flowering time genes associated with vernalization and the regulatory flowering networks in Chinese cabbage
  Won Yong Jung, Areum Lee, Jae Sun Moon, Youn-Sung Kim, Hye Sun Cho
  Plant Biotechnology Reports.2018; 12(5): 347.     CrossRef
• Genome-wide analysis of gene expression to distinguish photoperiod-dependent and -independent flowering in Brassicaceae
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  Genes & Genomics.2017; 39(2): 207.     CrossRef

Grafting has widely used in the agriculture of fruit-bearing crops and trees because rootstocks have a profound influence on many aspects of scion development and scion responses to the environmental changes including biotic and abiotic stress tolerance. These effects appear to result from the change of gene expression on scion, but only limited numbers of papers have been published demonstrating it. To identify altered expression of genes in Chinese cabbage, Chiifu(Brassica rapa ssp. pekinensis, inbred line) shoot was grafted on three Brassica rootstocks: mustard, turnip and broccoli. After head formation, Br300K microarray experiment was conducted using total RNAs from scion leaves collected in two different seasons, spring (June) and fall (October). A large number of differentially expressed genes (DEGs) were identified both in two seasonal samples, but DEGs were more notable in June sample than in October sample. However, the number of DEGs by three rootstocks were high in October with respect to up-regulation, but high in June for down-regulation. Categories of DEGs included metal ion binding, response to hormonal stimuli, response to endogenous stimuli, regulation of transcription, oxidation reduction and response to stress. Up-regulated genes in both June and October samples were similar in mustard and turnip rootstocks, but different in broccoli rootstock. Two genes were found to respond to all experimental conditions: Brapa_ESTC049008 (hypothetical protein) as an up-regulated gene and Brapa_ESTC016027 (CNGC12) as a down-regulated gene. Together with the previous reports, these results suggest that grafting-induced gene expression depends on the species involved.

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• Transcriptome analysis reveals the effects of grafting on sweetpotato scions during the full blooming stages
  Changhe Wei, Ming Li, Jia Qin, Yunfan Xu, Yizheng Zhang, Haiyan Wang
  Genes & Genomics.2019; 41(8): 895.     CrossRef
• Heterografting induced DNA methylation polymorphisms in Hevea brasiliensis
  Thomas K. Uthup, Rekha Karumamkandathil, Minimol Ravindran, Thakurdas Saha
  Planta.2018; 248(3): 579.     CrossRef