College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, University of East, Hohhot, 01000, Inner Mongolia, China.
Planta. 2024 Aug 31;260(4):84. doi: 10.1007/s00425-024-04509-9.
The PcHsp70-5 enhances drought stress tolerance in transgenic Arabidopsis thaliana by upregulating stress tolerance genes and antioxidant enzyme activities. Heat shock proteins (HSPs) constitute a class of evolutionarily conserved proteins synthesized by organisms in response to various adverse environmental stimuli such as elevated temperatures, drought, hormonal fluctuations, high salt concentrations, and mechanical stress. However, research on HSPs has predominantly focused on model plants and crops, whereas their functions in desert plants have not been well investigated. This study analyzed the transcriptome of Pugionium cornutum and identified the complete ORFs of 25 genes of the PcHsp70 family genes. Their expression levels under drought stress were investigated using existing RNA-seq data. PcHsp70-5 genes exhibited high expression levels in both roots and leaves under drought stress. Consequently, the PcHsp70-5 genes were cloned and transformed into Arabidopsis thaliana for further analysis of their roles in drought stress response. Real-time fluorescence quantitative PCR (qRT-PCR) analysis demonstrated that both, drought stress and ABA, induced PcHsp70-5 expression. Under drought conditions, transgenic Arabidopsis plants exhibited markedly enhanced growth compared to wild-type plants, as evidenced by improved survival rates, root length, fresh weight, chlorophyll content, and reduced levels of malondialdehyde (MDA) and hydrogen peroxide (HO) in leaves, indicating that PcHsp70-5 overexpression mitigated growth inhibition and oxidative damage induced by drought stress. Subsequent research revealed that PcHsp70-5 overexpression significantly augmented the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and increased the proline content in transgenic Arabidopsis under drought conditions, alongside a significant increase in the expression levels of genes related to stress tolerance. This suggests that PcHsp70-5 enhances drought stress tolerance in transgenic Arabidopsis by upregulating stress tolerance genes and antioxidant enzyme activities.
PcHsp70-5 通过上调应激耐受基因和抗氧化酶活性增强转基因拟南芥的耐旱性。热休克蛋白（HSPs）是一类在生物体中合成的进化上保守的蛋白质，它们对各种环境应激如高温、干旱、激素波动、高盐浓度和机械应激等作出响应。然而，关于 HSPs 的研究主要集中在模式植物和作物上，而它们在沙漠植物中的功能尚未得到很好的研究。本研究分析了沙芥的转录组，鉴定了 25 个 PcHsp70 家族基因的完整开放阅读框。利用现有的 RNA-seq 数据，研究了它们在干旱胁迫下的表达水平。PcHsp70-5 基因在干旱胁迫下根部和叶片中的表达水平均较高。因此，克隆了 PcHsp70-5 基因并转化到拟南芥中，以进一步分析它们在干旱胁迫响应中的作用。实时荧光定量 PCR（qRT-PCR）分析表明，干旱胁迫和 ABA 均诱导 PcHsp70-5 的表达。在干旱条件下，与野生型植物相比，转基因拟南芥植物的生长明显增强，表现在存活率、根长、鲜重、叶绿素含量的提高以及叶片中丙二醛（MDA）和过氧化氢（HO）水平的降低，表明 PcHsp70-5 的过表达减轻了干旱胁迫引起的生长抑制和氧化损伤。进一步的研究表明，PcHsp70-5 的过表达显著提高了 SOD、POD、CAT 的活性，并在干旱条件下增加了转基因拟南芥中的脯氨酸含量，同时与应激耐受相关的基因表达水平也显著提高。这表明 PcHsp70-5 通过上调应激耐受基因和抗氧化酶活性增强转基因拟南芥的耐旱性。
