Effect of vernalization on tuberization and flowering in the Tibetan turnip is associated with changes in the expression of FLC homologues  

作　　者：Yan Zheng Landi Luo Yuanyuan Liu Yunqiang Yang Chuntao Wang Xiangxiang Kong Yongping Yang 

机构地区：[1]Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China [2]Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China [3]University of Chinese Academy of Sciences, Beijing 100049, China [4]School of Ecology and Environmental Science, Yunnan University, Kunming 650504, China

出　　处：《Plant Diversity》2018年第2期50-56,共7页植物多样性（英文版）

基　　金：supported by the National Science Foundation of China(No.31500221,31590823 and 31601999);the West Light Foundation of the Chinese Academy of Sciences by XXK

摘　　要：The turnip(Brassica rapa var. rapa) is a biennial crop that is planted in late summer/early fall and forms fleshy tubers for food in temperate regions. The harvested tubers then overwinter and are planted again the next spring for flowering and seeds. FLOWERING LOCUS C(FLC) is a MADS-box transcription factor that acts as a major repressor of floral transition by suppressing the flowering promoters FT and SOC1. Here we show that vernalization effectively represses tuber formation and promotes flowering in Tibetan turnip. We functionally characterized four FLC homologues(BrrFLC1,FLC2, FLC3, and FLC5), and found that BrrFLC2 and BrrFLC1 play a major role in repressing flowering in turnip and in transgenic Arabidopsis. In contrast, tuber formation was correlated with BrrFLC1 expression in the hypocotyl and was repressed under cold treatment following the quantitative downregulation of BrrFLC1. Grafting experiments of non-vernalized and vernalized turnips revealed that vernalization independently suppressed tuberization in the tuber or hypocotyl of the rootstock or scion, which occurred in parallel with the reduction in BrrFLC1 activity. Together, our results demonstrate that the Tibetan turnip is highly responsive to cold exposure, which is associated with the expression levels of BrrFLC genes.The turnip （Brassica rapa var. rapa） is a biennial crop that is planted in late summer/early fall and forms fleshy tubers for food in temperate regions. The harvested tubers then overwinter and are planted again the next spring for flowering and seeds. FLOWERING LOCUS C （FLC） is a MADS-box transcription factor that acts as a major repressor of floral transition by suppressing the flowering promoters FF and SOC1. Here we show that vernalization effectively represses tuber formation and promotes flowering in Tibetan turnip. We functionally characterized four FLC homologues （BrrFLCI, FLC2, FLC3, and FLCS）, and found that BrrFLC2 and BrrFLC1 play a major role in repressing flowering in turnip and in transgenic Arabidopsis. In contrast, tuber formation was correlated with BrrFLCI expression in the hypocotyl and was repressed under cold treatment following the quantitative downregulation of BrrFLCI. Grafting experiments of non-vernalized and vernalized turnips revealed that vernalization independently suppressed tuberization in the tuber or hypocotyl of the rootstock or scion, which occurred in parallel with the reduction in BrrFLCI activity. Together, our results demonstrate that the Tibetan turnip is highly responsive to cold exposure, which is associated with the expression levels of BrrFLC genes.

关 键 词：Tibetan turnip TUBERIZATION FLOWERING BrrFLC genes VERNALIZATION 

分 类 号：Q[生物学]