囊泡运输在植物对非生物胁迫的耐受性中起着重要作用。然而,囊泡形成相关蛋白CaSec16(COPII外壳组装蛋白Sec16样)在辣椒对盐胁迫的耐受性中的贡献尚不清楚。在这项研究中,我们报道了盐胁迫上调CaSec16的表达。与对照相比,CaSec16沉默的胡椒的耐盐性受到损害,由相应的表型和生理指标显示,比如生长点的死亡,严重的叶子枯萎,相对漏电(REL)的增量越高,总叶绿素含量较低,死亡细胞的积累越多,H2O2、丙二醛(MDA)、和脯氨酸(Pro),以及抑制耐盐标记基因的诱导和囊泡运输。相比之下,CaSec16的瞬时过表达增强了辣椒的耐盐性。此外,异源诱导的CaSec16蛋白不能增强大肠杆菌的耐盐性,缺乏囊泡运输系统的有机体。通过酵母双杂交方法,一种锚蛋白,CaANK2B,被鉴定为CaSec16的相互作用蛋白。盐胁迫过程中CaANK2B的表达量呈下降趋势。与对照相比,瞬时过表达CaANK2B的辣椒植物表现出增加的耐盐性,而CaANK2B沉默的那些表现出降低的耐盐性。一起来看,囊泡形成相关蛋白CaSec16及其相互作用伴侣CaANK2B均能提高辣椒对盐胁迫的耐受性。
Vesicle transport plays important roles in plant tolerance against abiotic stresses. However, the contribution of a vesicle formation related protein CaSec16 (COPII coat assembly protein Sec16-like) in pepper tolerance to salt stress remains unclear. In this study, we report that the expression of CaSec16 was upregulated by salt stress. Compared to the control, the salt tolerance of pepper with CaSec16-silenced was compromised, which was shown by the corresponding phenotypes and physiological indexes, such as the death of growing point, the aggravated leaf wilting, the higher increment of relative electric leakage (REL), the lower content of total chlorophyll, the higher accumulation of dead cells, H2O2, malonaldehyde (MDA), and proline (Pro), and the inhibited induction of marker genes for salt-tolerance and vesicle transport. In contrast, the salt tolerance of pepper was enhanced by the transient overexpression of CaSec16. In addition, heterogeneously induced CaSec16 protein did not enhance the salt tolerance of Escherichia coli, an organism lacking the vesicle transport system. By yeast two-hybrid method, an ankyrin protein, CaANK2B, was identified as the interacting protein of CaSec16. The expression of CaANK2B showed a downward trend during the process of salt stress. Compared with the control, pepper plants with transient-overexpression of CaANK2B displayed increased salt tolerance, whereas those with CaANK2B-silenced exhibited reduced salt tolerance. Taken together, both the vesicle formation related protein CaSec16 and its interaction partner CaANK2B can improve the pepper tolerance to salt stress.