Open AccessNbALD1 mediates resistance to turnip mosaic virus by regulating the accumulation of salicylic acid and the ethylene pathway in Nicotiana benthamiana
Author(s) -
Wang Shu,
Han Kelei,
Peng Jiejun,
Zhao Jinping,
Jiang Liangliang,
Lu Yuwen,
Zheng Hongying,
Lin Lin,
Chen Jianping,
Yan Fei
Publication year - 2019
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12808
Subject(s) - turnip mosaic virus , nicotiana benthamiana , salicylic acid , biology , gene silencing , rna silencing , rna interference , plant disease resistance , virology , plant virus , potyvirus , virus , biochemistry , rna , gene
Summary AGD2‐LIKE DEFENCE RESPONSE PROTEIN 1 (ALD1) triggers plant defence against bacterial and fungal pathogens by regulating the salicylic acid (SA) pathway and an unknown SA‐independent pathway. We now show that Nicotiana benthamiana ALD1 is involved in defence against a virus and that the ethylene pathway also participates in ALD1 ‐mediated resistance. NbALD1 was up‐regulated in plants infected with turnip mosaic virus (TuMV). Silencing of NbALD1 facilitated TuMV infection, while overexpression of NbALD1 or exogenous application of pipecolic acid (Pip), the downstream product of ALD1 , enhanced resistance to TuMV. The SA content was lower in NbALD1 ‐silenced plants and higher where NbALD1 was overexpressed or following Pip treatments. SA mediated resistance to TuMV and was required for NbALD1 ‐mediated resistance. However, on NahG plants (in which SA cannot accumulate), Pip treatment still alleviated susceptibility to TuMV, further demonstrating the presence of an SA‐independent resistance pathway. The ethylene precursor, 1‐aminocyclopropanecarboxylic acid (ACC), accumulated in NbALD1 ‐silenced plants but was reduced in plants overexpressing NbALD1 or treated with Pip. Silencing of ACS1 , a key gene in the ethylene pathway, alleviated the susceptibility of NbALD1 ‐silenced plants to TuMV, while exogenous application of ACC compromised the resistance of Pip‐treated or NbALD1 transgenic plants. The results indicate that NbALD1 mediates resistance to TuMV by positively regulating the resistant SA pathway and negatively regulating the susceptible ethylene pathway.