Abstract

Organisms can produce heat shock proteins (HSPs) in response to elevated temperatures and other abiotic stresses. However, the function of HSPs, including small heat shock proteins (sHSPs), in stress tolerance is not fully explored. To improve our understanding of sHSPs, we isolated a gene of sHSPs from David lily (Lilium davidii Duchartre) called LimHSP16.45. Results reveal that LimHSP16.45 is a cytosolic class II sHSP. The HSP17.6II of Arabidopsis thaliana belongs to the HSP20 chaperone protein and is similar to Lim16.45HSP of David lily in terms of size and structure. Both genes have a small heat shock-like alpha-crystallin domain (ACD) structure. To further study the function of Lim16.45HSP, we overexpress it in Arabidopsis hsp17.6II mutant. Then, we detect the expression of LimHSP16.45 in transgenic plant under abiotic stresses and analyze the heat tolerance of transgenic plant. In addition, we measure the activity of three antioxidant enzymes (peroxidase, catalase and superoxide dismutase) and the content of soluble sugar and proline in transgenic plants under abiotic stresses.We found that transgenic plant is tolerant to heat and oxidative stresses given its increased survival rate relative to the hsp17.6II and wild type. Moreover, the content of soluble sugar and proline considerably increase in the transgenic plant. These results support the positive role of LimHSP16.45 in response to heat stress in plants. We suspect that LimHSP16.45 enhances plant tolerance to abiotic stresses by stimulating the activity of ROS-scavenging enzymes and other protective enzymes and increasing the synthesis of proline.

中文翻译：

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小热激蛋白LimHSP16.45在拟南芥hsp17.6II突变体中的过表达增强了对非生物胁迫的耐受性

摘要

生物可以响应高温和其他非生物胁迫而产生热激蛋白（HSP）。但是，HSPs，包括小的热激蛋白（sHSPs），在压力耐受性中的功能尚未得到充分研究。为了增进对sHSPs的了解，我们从戴维·莉莉（Lilium davidii Duchartre）分离了一个名为LimHSP16.45的sHSPs基因。结果显示，LimHSP16.45是胞质II类sHSP。拟南芥的HSP17.6II属于HSP20伴侣蛋白，在大小和结构上与David lily的Lim16.45HSP相似。这两个基因都有一个小的热激样α-晶状体结构域（ACD）结构。为了进一步研究Lim16.45HSP的功能，我们在拟南芥hsp17.6II中过表达它突变体。然后，我们检测了LimHSP16.45在非生物胁迫下在转基因植物中的表达，并分析了转基因植物的耐热性。此外，我们还测量了非生物胁迫下转基因植物中三种抗氧化酶（过氧化物酶，过氧化氢酶和超氧化物歧化酶）的活性以及可溶性糖和脯氨酸的含量，发现转基因植物具有较高的生存能力，因此能够耐受热和氧化胁迫相对于hsp17.6II的速率和野生型。此外，转基因植物中可溶性糖和脯氨酸的含量显着增加。这些结果支持了LimHSP16.45在响应植物热胁迫中的积极作用。我们怀疑LimHSP16.45通过刺激ROS清除酶和其他保护性酶的活性并增加脯氨酸的合成来增强植物对非生物胁迫的耐受性。