Department of Plant and Soil Sciences, Private Bag X20, Hatfield, Pretoria, 0001, South Africa; Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.
Department of Plant and Soil Sciences, Private Bag X20, Hatfield, Pretoria, 0001, South Africa; Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa.
Plant Physiol Biochem. 2020 Apr;149:286-293. doi: 10.1016/j.plaphy.2020.02.007. Epub 2020 Feb 15.
Serine protease inhibitors (SPIs) play an important role in cell survival, development and host defense. In plants, serine protease inhibitors such as the Kunitz-type inhibitor (KTI) and the Bowman-Birk inhibitor (BBI) have been shown to be induced in response to abiotic stress such as salinity and drought resulting in tolerance to these stresses. In this study, Arabidopsis thaliana (T3) plants overexpressing the BBI gene from maize were generated and subjected to drought stress in order to study the role of BBI protease inhibitor in drought tolerance. Drought treatment of four-week-old Arabidopsis plants was performed by withholding water from plants for nine days and harvested plant material was used for physiological and biochemical analysis. The transgenic lines exhibited normal growth after nine days of drought as compared to the wild-type. The results also showed a higher leaf relative water content (RWC) in transgenic lines when compared to the wild-type (WT), with line 2 having the highest RWC of 72% and the WT having the lowest RWC of 32%. Trypsin-inhibitor activity indicated that the total protein of the positive transgenic plants had stronger protease inhibitory activity than the wild-type. Transgenic lines overexpressing BBI also showed reduced lipid peroxidation (MDA content) as well as enhanced activity of antioxidants glutathione-s-transferase (GST) and ascorbate peroxidase (APX). These results suggest that BBI protease inhibitor leads to drought tolerance associated with reduction in drought-induced oxidative stress.
丝氨酸蛋白酶抑制剂 (SPIs) 在细胞存活、发育和宿主防御中发挥着重要作用。在植物中，丝氨酸蛋白酶抑制剂，如 Kunitz 型抑制剂 (KTI) 和 Bowman-Birk 抑制剂 (BBI)，已被证明可响应非生物胁迫（如盐度和干旱）而被诱导，从而产生对这些胁迫的耐受性。在这项研究中，生成了拟南芥 (T3) 植物过表达来自玉米的 BBI 基因，并对其进行干旱胁迫处理，以研究 BBI 蛋白酶抑制剂在耐旱性中的作用。通过将植物停水 9 天来对四叶期拟南芥植物进行干旱处理，并采集植物材料进行生理生化分析。与野生型相比，经过 9 天干旱处理后，转基因系表现出正常的生长。结果还表明，与野生型 (WT) 相比，转基因系的叶片相对含水量 (RWC) 更高，其中 2 号系的 RWC 最高，为 72%，而 WT 的 RWC 最低，为 32%。胰蛋白酶抑制剂活性表明，阳性转基因植物的总蛋白具有比野生型更强的蛋白酶抑制活性。过表达 BBI 的转基因系也表现出脂质过氧化（MDA 含量）减少以及抗氧化剂谷胱甘肽-S-转移酶 (GST) 和抗坏血酸过氧化物酶 (APX) 活性增强。这些结果表明，BBI 蛋白酶抑制剂导致与减少干旱诱导的氧化应激相关的耐旱性。
