Tobacco alpha-expansin EXPA4 plays a role in Nicotiana benthamiana defence against Tobacco mosaic virus
Tobacco alpha-expansin EXPA4 plays a role in Nicotiana benthamiana defence against Tobacco mosaic virus
复制标题
烟草α-扩展蛋白 EXPA4 在本塞姆氏烟草防御烟草花叶病毒中发挥作用
DOI：
10.1007/s00425-017-2785-6
复制
发表时间：
2018-02-01
期刊：
影响因子：
4.3
通讯作者：
Xi, De-Hui
中科院分区：
文献类型：
--
作者：
Chen, Li-Juan;Zou, Wen-Shan;Xi, De-Hui
烟草EXPA4在烟草抵御病毒攻击中起作用，并影响烟草的抗氧化代谢和植物激素介导的免疫反应。Expansins是一种细胞壁松弛蛋白，因其在植物生长过程中对细胞壁的伸展具有内源功能而闻名。膨胀素对植物生长、发育过程和环境胁迫响应的影响已经得到了广泛的研究。然而，Expansins在植物抗病毒方面的研究报道很少。本研究通过病毒诱导的基因沉默(VIGS)和农杆菌介导的瞬时过表达技术，研究了烟草α-膨胀素4(EXPA4)基因在调控烟草对烟草花叶病毒(TMV-GFP)抗性中的作用。结果表明，沉默EXPA4降低了本氏拟青霉对TMV-GFP的敏感性，EXPA4过表达促进了病毒在烟草上的繁殖。此外，我们的数据表明，病毒积累对EXPA4表达水平的响应可能进一步影响病毒接种诱导的烟草体内的抗氧化代谢和植物激素相关途径。带有TMV-GFP的EXPA4沉默植株具有增强抗氧化酶活性的作用，而在接种病毒的35S：EXPA4植株中，这些抗氧化酶活性被下调。在EXPA4沉默的植株中，TMV-GFP诱导的水杨酸积累和SA介导的防御基因表达上调，而在35S：EXPA4植株中表达下调。此外，VIGS方法与外源植物激素处理相结合，表明EXPA4对不同的植物激素有不同的反应。综上所述，这些结果表明EXPA4在烟草对病毒病原体的防御中发挥作用。
Tobacco EXPA4 plays a role in Nicotiana benthamiana defence against virus attack and affects antioxidative metabolism and phytohormone-mediated immunity responses in tobacco.Expansins are cell wall-loosening proteins known for their endogenous functions in cell wall extensibility during plant growth. The effects of expansins on plant growth, developmental processes and environment stress responses have been well studied. However, the exploration of expansins in plant virus resistance is rarely reported. In the present study, virus-induced gene silencing (VIGS) and Agrobacterium-mediated transient overexpression were conducted to investigate the role of Nicotiana tabacum alpha-expansin 4 (EXPA4) in modulating Tobacco mosaic virus (TMV-GFP) resistance in Nicotiana benthamiana. The results indicated that silencing of EXPA4 reduced the sensitivity of N. benthamiana to TMV-GFP, and EXPA4 overexpression accelerated virus reproduction on tobacco. In addition, our data suggested that the changes of virus accumulation in response to EXPA4 expression levels could further affect the antioxidative metabolism and phytohormone-related pathways in tobacco induced by virus inoculation. EXPA4-silenced plants with TMV-GFP have enhanced antioxidant enzymes activities, which were down-regulated in virus-inoculated 35S:EXPA4 plants. Salicylic acid accumulation and SA-mediated defence genes induced by TMV-GFP were up-regulated in EXPA4-silenced plants, but depressed in 35S:EXPA4 plants. Furthermore, a VIGS approach was used in combination with exogenous phytohormone treatments, suggesting that EXPA4 has different responses to different phytohormones. Taken together, these results suggested that EXPA4 plays a role in tobacco defence against viral pathogens.