Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Center for Genomics and Biotechnology, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China.
National Engineering Research Center of Sugarcane, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
BMC Plant Biol. 2019 Sep 2;19(1):381. doi: 10.1186/s12870-019-1986-5.
Trehalose-6-phosphate phosphatases (TPPs), which are encoded by members of the TPP gene family, can improve the drought tolerance of plants. However, the molecular mechanisms underlying the dynamic regulation of TPP genes during drought stress remain unclear. In this study, we explored the function of an Arabidopsis TPP gene by conducting comparative analyses of a loss-of-function mutant and overexpression lines.
The loss-of-function mutation of Arabidopsis thaliana TPPF, a member of the TPP gene family, resulted in a drought-sensitive phenotype, while a line overexpressing TPPF showed significantly increased drought tolerance and trehalose accumulation. Compared with wild-type plants, tppf1 mutants accumulated more HO under drought, while AtTPPF-overexpressing plants accumulated less HO under drought. Overexpression of AtTPPF led to increased contents of trehalose, sucrose, and total soluble sugars under drought conditions; these compounds may play a role in scavenging reactive oxygen species. Yeast one-hybrid and luciferase activity assays revealed that DREB1A could bind to the DRE/CRT element within the AtTPPF promoter and activate the expression of AtTPPF. A transcriptome analysis of the TPPF-overexpressing plants revealed that the expression levels of drought-repressed genes involved in electron transport activity and cell wall modification were upregulated, while those of stress-related transcription factors related to water deprivation were downregulated. These results indicate that, as well as its involvement in regulating trehalose and soluble sugars, AtTPPF is involved in regulating the transcription of stress-responsive genes.
AtTPPF functions in regulating levels of trehalose, reactive oxygen species, and sucrose levels during drought stress, and the expression of AtTPPF is activated by DREB1A in Arabidopsis. These findings shed light on the molecular mechanism by which AtTPPF regulates the response to drought stress.
海藻糖-6-磷酸磷酸酶（TPPs）由 TPP 基因家族成员编码，能够提高植物的抗旱能力。然而，在干旱胁迫下 TPP 基因的动态调控的分子机制尚不清楚。在本研究中，我们通过对功能丧失突变体和过表达系进行比较分析，探讨了拟南芥 TPP 基因的功能。
TPP 基因家族成员拟南芥 TPPF 的功能丧失突变导致干旱敏感表型，而过表达 TPPF 的系表现出显著增强的耐旱性和海藻糖积累。与野生型植物相比，tppf1 突变体在干旱下积累更多的 HO，而过表达 AtTPPF 的植物在干旱下积累更少的 HO。过表达 AtTPPF 导致干旱条件下海藻糖、蔗糖和总可溶性糖含量增加；这些化合物可能在清除活性氧中发挥作用。酵母单杂交和荧光素酶活性测定表明，DREB1A 可以结合 AtTPPF 启动子中的 DRE/CRT 元件并激活 AtTPPF 的表达。对过表达 TPPF 的植物进行转录组分析表明，与电子传递活性和细胞壁修饰相关的干旱抑制基因的表达水平上调，而与水分胁迫相关的应激相关转录因子的表达水平下调。这些结果表明，除了参与调节海藻糖和可溶性糖外，AtTPPF 还参与调节应激响应基因的转录。
AtTPPF 在干旱胁迫下调节海藻糖、活性氧和蔗糖水平，DREB1A 激活拟南芥中 AtTPPF 的表达。这些发现揭示了 AtTPPF 调节对干旱胁迫响应的分子机制。
