Zhang Jing, Li Qing-Fei, Huang Wei-Wei, Xu Xiao-Yong, Zhang Xin-Ling, Hui Mai-Xia, Zhang Ming-Ke, Zhang Lu-Gang
College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China.
Int J Mol Sci. 2013 Jun 27;14(7):13346-59. doi: 10.3390/ijms140713346.
Radish floral bud abortion (FBA) is an adverse biological phenomenon that occurs during reproduction. Although FBA is a frequent occurrence, its molecular mechanism remains unknown. A transcript-derived fragment (TDF72), which was obtained by cDNA amplified fragment length polymorphism (cDNA-AFLP), was up-regulated in the aborted buds and exhibited 89% sequence homology with the AtγVPE gene. In this study, TDF72 was used to clarify the role of VPE in FBA by isolation of the VPE gene RsVPE1 from radish flower buds. The full-length genomic DNA was 2346 bp including nine exons and eight introns. The full-length cDNA was 1825 bp, containing a complete open reading frame (ORF) of 1470 bp, which encoded a predicted protein containing 489 amino acid residues, with a calculated molecular mass of 53.735 kDa. Expression analysis demonstrated that RsVPE1 was expressed in all tested organs of radish at different levels. Highest expression was detected in aborted flower buds, suggesting that RsVPE1 has a role in FBA. In order to analyze the role of RsVPE1 in FBA, RsVPE1 was overexpressed in transgenic Arabidopsis thaliana plants. Aborted flower buds appeared in transgenic plants subjected to heat stress. In addition, RsVPE1 expression in the transgenic plants reached a maximum when subjected to heat stress for 24 h and increased by 2.1-fold to 2.8-fold in three homozygous transgenic lines. These results indicated that RsVPE1 led to FBA when its expression levels exceeded a particular threshold, and provided evidence for the involvement of RsVPE1 in promoting FBA under heat stress.
萝卜花芽败育（FBA）是一种在生殖过程中出现的不良生物学现象。尽管FBA经常发生，但其分子机制仍不清楚。通过cDNA扩增片段长度多态性（cDNA-AFLP）获得的一个转录本衍生片段（TDF72）在败育芽中上调，并且与AtγVPE基因具有89%的序列同源性。在本研究中，通过从萝卜花芽中分离VPE基因RsVPE1，利用TDF72来阐明VPE在FBA中的作用。基因组DNA全长2346 bp，包括9个外显子和8个内含子。cDNA全长1825 bp，包含一个1470 bp的完整开放阅读框（ORF），编码一个预测的含有489个氨基酸残基的蛋白质，计算分子量为53.735 kDa。表达分析表明，RsVPE1在萝卜所有测试器官中均有不同水平的表达。在败育花芽中检测到最高表达，表明RsVPE1在FBA中起作用。为了分析RsVPE1在FBA中的作用，在转基因拟南芥植物中过表达RsVPE1。遭受热胁迫的转基因植物出现了败育花芽。此外，转基因植物在热胁迫24 h时RsVPE1表达达到最大值，并且在三个纯合转基因株系中增加了2.1倍至2.8倍。这些结果表明，当RsVPE1的表达水平超过特定阈值时会导致FBA，并为RsVPE1在热胁迫下促进FBA中的作用提供了证据。
