Gong Benhe, Yi Jin, Wu Jian, Sui Juanjuan, Khan Muhammad Ali, Wu Ze, Zhong Xionghui, Seng Shanshan, He Junna, Yi Mingfang
Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Yuan Mingyuan Western Road 2#, Beijing, 100193, China.
Plant Cell Rep. 2014 Sep;33(9):1519-33. doi: 10.1007/s00299-014-1635-2. Epub 2014 May 30.
A heat stress transcription factor LlHSFA1 in lily and its relationship with LlHSFA2 was investigated, and its function in enhancing thermotolerance was confirmed by analyzing transgenic Arabidopsis thaliana overexpressed LlHSFA1. A large family of heat stress transcription factors that are involved in the heat stress response in plants can induce the expression of multiple genes related to thermotolerance including heat-shock proteins. In this study, a novel class A1 HSF named LlHSFA1 was isolated from leaves of lily (Lilium longiflorum cv. 'White Heaven') using the rapid amplification of cDNA ends technique. Analysis of the deduced amino acid sequence and construction of a phylogenetic tree showed that LlHSFA1 contained five critical domains and motifs and belonged to the A1 family of HSFs. Following the heat treatment of lily leaves, transcription of LlHSFA1 was induced to a varying extent, related to the time of measurement. The induced expression peak of LlHSFA1 occurred prior to that of LlHSFA2, during the early phase of heat stress. Following transient expression of LlHSFA1 in Nicotiana benthamiana, LlHSFA1 was found to be localized in both the nucleus and the cytoplasm. Analysis using bimolecular fluorescence complementation and a yeast two-hybrid assay demonstrated that LlHSFA1 could interact with LlHSFA2. Use of a yeast one-hybrid assay confirmed that LlHSFA1 had transcriptional activation activity. In transgenic Arabidopsis lines overexpressing LlHSFA1 under unstressed conditions, the expression of some putative target genes was up-regulated, in comparison with expression in wild-type plants, and furthermore, the thermotolerance of the transgenic lines was enhanced. Overall, LlHSFA1 was demonstrated to play an important role in the heat stress response of lily and to be a novel candidate gene for application in lily breeding, using genetic modification approaches.
研究了百合中的热胁迫转录因子LlHSFA1及其与LlHSFA2的关系，并通过分析过表达LlHSFA1的转基因拟南芥证实了其在增强耐热性方面的功能。植物中参与热胁迫反应的一大类热胁迫转录因子可诱导包括热休克蛋白在内的多个与耐热性相关基因的表达。在本研究中，利用cDNA末端快速扩增技术从百合（Lilium longiflorum cv. 'White Heaven'）叶片中分离出一个新的A1类热激转录因子LlHSFA1。对推导的氨基酸序列进行分析并构建系统发育树表明，LlHSFA1包含五个关键结构域和基序，属于热激转录因子的A1家族。对百合叶片进行热处理后，LlHSFA1的转录在不同程度上被诱导，这与测量时间有关。LlHSFA1的诱导表达峰值出现在热胁迫早期，早于LlHSFA2的诱导表达峰值。在本氏烟草中瞬时表达LlHSFA1后，发现LlHSFA1定位于细胞核和细胞质中。利用双分子荧光互补和酵母双杂交分析表明，LlHSFA1可以与LlHSFA2相互作用。酵母单杂交分析证实LlHSFA1具有转录激活活性。与野生型植物相比，在非胁迫条件下过表达LlHSFA1的转基因拟南芥株系中，一些假定靶基因的表达上调，此外，转基因株系的耐热性增强。总体而言，LlHSFA1被证明在百合的热胁迫反应中起重要作用，并且是利用基因改造方法应用于百合育种的一个新的候选基因。
