Ethylene‐induced NbMYB4L is involved in resistance against tobacco mosaic virus in Nicotiana benthamiana

Abstract

Several MYB transcription factors are known to play important roles in plant resistance to environmental stressors. However, the mechanism governing the involvement of MYBs in regulating tobacco mosaic virus (TMV) resistance in plants is still unclear. In this study, we found that not only is Nicotiana benthamiana MYB4-like involved in defence against TMV, but also that the ethylene pathway participates in MYB4L-mediated resistance. Transcription of NbMYB4L was up-regulated in N. benthamiana infected with TMV. Silencing of NbMYB4L led to intensified TMV replication, whereas overexpression of NbMYB4L induced significant resistance to TMV. Transcription of NbMYB4L was greater in 1-aminocyclopropanecarboxylic acid (ACC, ethylene precursor)pretreated plants but lower when the ethylene signalling pathway was blocked during TMV infection. Gene expression analysis showed that the transcription of NbMYB4L was largely suppressed in ETHYLENE INSENSITIVE 3-like 1(EIL1)-silenced plants. The results of electrophoretic mobility shift assay and chromatin immunoprecipitationquantitative PCR (ChIP-qPCR) experiments indicated that NbEIL1 could directly bind to two specific regions of the NbMYB4L promoter. Furthermore, a luciferase assay revealed that NbEIL1 significantly induced the reporter activity of the MYB4L promoter in N. benthamiana. These results point to NbEIL1 functioning as a positive regulator of NbMYB4L transcription in N. benthamiana against TMV. Collectively, our work reveals that EIL1 and MYB4L constitute a coherent feed-forward loop involved in the robust regulation of resistance to TMV in N. benthamiana.

Integrated next-generation sequencing and comparative transcriptomic analysis of leaves provides novel insights into the ethylene pathway of Chrysanthemum morifolium in response to a Chinese isolate of chrysanthemum virus B

“…Increasing evidence shows that ethylene is one of the key modulators of plant responses to viral infections [ 60 , 65 , 66 ]. In the present study, we compared the expression of the ethylene biosynthesis- and signaling pathway-related genes of C. morifolium in response to CVB-CN infection based on their GO terms.…”

“…For example, in N. tabacum , overexpression of NtERF5 can increase host resistance to TMV infection [ 60 ]. Likewise, in N. benthamiana , overexpression of NbMYB4L , an ethylene-induced transcription factor, also results in increased resistance to TMV [ 66 ]. Recently, CaERF1A was reported to be strongly induced by P0 of TMV (TMV-P0) and knockdown of CaERF1A negatively affected the TMV-P0-mediated hypersensitive response in hot pepper [ 70 ].…”

“…Besides its roles in plant development, fruit ripening, and organ senescence, ethylene is also a crucial modulator of plant responses to abiotic and biotic stimuli, including viral infections [ 65 , 66 , 79 , 80 ]. Ethylene has been shown to modulate host defenses against viral infections in both positive and negative manners [ 39 , 66 , 80 , 81 ].…”

“…Besides its roles in plant development, fruit ripening, and organ senescence, ethylene is also a crucial modulator of plant responses to abiotic and biotic stimuli, including viral infections [ 65 , 66 , 79 , 80 ]. Ethylene has been shown to modulate host defenses against viral infections in both positive and negative manners [ 39 , 66 , 80 , 81 ]. For example, in N. tabacum , ethylene pathway has a crucial role in systemic resistance to Chilli veinal mottle virus (ChiVMV), and silencing of the ethylene biosynthetic and signaling components accelerate ChiVMV-induced cell death [ 81 ].…”

The Ubiquitin–Proteasome System (UPS) and Viral Infection in Plants

“…At this moment, CRLs are likely the best-characterized E3s in plants [ 22 ]. CRLs participate in almost all aspects of plant growth and development, auxin signaling, JA signaling, and regulation of antiviral response [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. In the CRL complex, the cullin protein serves as an elongated scaffold, recruiting the RING box protein 1 (RBX1) and E2 to its carboxy (C)-terminal region and binding a substrate adaptor to its amino (N)-terminal region.…”