Beijing Key Laboratory of Development and Quality Control of Ornamental Crops, College of Horticulture, China Agricultural University, Beijing 100193, China.
Key Laboratory of East China Urban Agriculture, Ministry of Agriculture and Rural Affairs, Institute of Leisure Agriculture, Shandong Academy of Agricultural Sciences, Jinan 250100, China.
Int J Mol Sci. 2022 Jan 5;23(1):572. doi: 10.3390/ijms23010572.
Heat stress severely affects the annual agricultural production. Heat stress transcription factors (HSFs) represent a critical regulatory juncture in the heat stress response (HSR) of plants. The HsfA1-dependent pathway has been explored well, but the regulatory mechanism of the HsfA1-independent pathway is still under-investigated. In the present research, HsfA4, an important gene of the HsfA1-independent pathway, was isolated from lilies () using the RACE method, which encodes 435 amino acids. LlHsfA4 contains a typical domain of HSFs and belongs to the HSF A4 family, according to homology comparisons and phylogenetic analysis. was mainly expressed in leaves and was induced by heat stress and HO using qRT-PCR and GUS staining in transgenic . LlHsfA4 had transactivation activity and was located in the nucleus and cytoplasm through a yeast one hybrid system and through transient expression in lily protoplasts. Over expressing in enhanced its basic thermotolerance, but acquired thermotolerance was not achieved. Further research found that heat stress could increase HO content in lily leaves and reduced HO accumulation in transgenic plants, which was consistent with the up-regulation of HSR downstream genes such as (), Galactinol synthase1 (), (), () and the ROS-scavenging enzyme (). In conclusion, these results indicate that LlHsfA4 plays important roles in heat stress response through regulating the ROS metabolism in lilies.
热应激严重影响着农业的年度生产。热应激转录因子（HSFs）在植物的热应激反应（HSR）中是一个关键的调控环节。HsfA1 依赖的途径已经得到了很好的研究，但 HsfA1 非依赖途径的调控机制仍未被充分研究。在本研究中，通过 RACE 方法从百合中分离出 HsfA4，这是 HsfA1 非依赖途径中的一个重要基因，编码 435 个氨基酸。LlHsfA4 含有 HSFs 的典型结构域，根据同源性比较和系统发育分析，属于 HSF A4 家族。qRT-PCR 和 GUS 染色显示，在转基因百合中，LlHsfA4 主要在叶片中表达，并受到热应激和 HO 的诱导。LlHsfA4 具有转录激活活性，通过酵母单杂交系统和在百合原生质体中的瞬时表达，定位在细胞核和细胞质中。在 中过量表达 增强了其基础耐热性，但未获得耐热性。进一步的研究发现，热应激可以增加百合叶片中的 HO 含量，并减少转基因植物中 HO 的积累，这与 HSR 下游基因如 ()、半乳糖醇合酶 1 ()、()、()和 ROS 清除酶 ()的上调一致。综上所述，这些结果表明，LlHsfA4 通过调节百合中 ROS 代谢在热应激反应中发挥重要作用。
