State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, 271018, China.
College of Life Sciences, Zaozhuang University, Zaozhuang, 277000, China.
J Integr Plant Biol. 2020 May;62(5):631-651. doi: 10.1111/jipb.12842. Epub 2019 Oct 18.
U-box E3 ubiquitin ligases play important roles in the ubiquitin/26S proteasome machinery and in abiotic stress responses. TaPUB1-overexpressing wheat (Triticum aestivum L.) were generated to evaluate its function in salt tolerance. These plants had more salt stress tolerance during seedling and flowering stages, whereas the TaPUB1-RNA interference (RNAi)-mediated knock-down transgenic wheat showed more salt stress sensitivity than the wild type (WT). TaPUB1 overexpression upregulated the expression of genes related to ion channels and increased the net root Na efflux, but decreased the net K efflux and H influx, thereby maintaining a low cytosolic Na /K ratio, compared with the WT. However, RNAi-mediated knock-down plants showed the opposite response to salt stress. TaPUB1 could induce the expression of some genes that improved the antioxidant capacity of plants under salt stress. TaPUB1 also interacted with TaMP (Triticum aestivum α-mannosidase protein), a regulator playing an important role in salt response in yeast and in plants. Thus, low cytosolic Na /K ratios and better antioxidant enzyme activities could be maintained in wheat with overexpression of TaPUB1 under salt stress. Therefore, we conclude that the U-box E3 ubiquitin ligase TaPUB1 positively regulates salt stress tolerance in wheat.
U-box E3 泛素连接酶在泛素/26S 蛋白酶体机制和非生物胁迫反应中发挥重要作用。为了评估 TaPUB1 在耐盐性中的功能，我们生成了 TaPUB1 过表达的小麦（Triticum aestivum L.）。这些植物在幼苗期和花期具有更高的耐盐性，而 TaPUB1-RNA 干扰（RNAi）介导的敲低转基因小麦比野生型（WT）对盐更敏感。TaPUB1 过表达上调了与离子通道相关的基因的表达，并增加了根净 Na 外排，但降低了根净 K 外排和 H 内流，从而维持了低胞质 Na /K 比值，与 WT 相比。然而，RNAi 介导的敲低植物对盐胁迫表现出相反的反应。TaPUB1 可以诱导一些基因的表达，这些基因可以提高植物在盐胁迫下的抗氧化能力。TaPUB1 还与 TaMP（小麦 α-甘露糖苷酶蛋白）相互作用，TaMP 是酵母和植物中盐响应的重要调节因子。因此，在盐胁迫下，过表达 TaPUB1 的小麦可以维持较低的胞质 Na /K 比值和更好的抗氧化酶活性。因此，我们得出结论，U-box E3 泛素连接酶 TaPUB1 正向调节小麦的耐盐性。
