Maize AKINβγ Proteins Interact with P8 of Rice Black Streaked Dwarf Virus and Inhibit Viral Infection

Abstract

Rice black streaked dwarf virus (RBSDV) is an important agent causing maize rough dwarf disease, whereas the host factors responding to RBSDV infection are poorly understood. To uncover the molecular interactions between RBSDV and maize, a yeast two-hybrid screen of a maize cDNA library was carried out using the viral P8 protein as a bait. ZmAKINβγ-1 and ZmAKINβγ-2 (βγ subunit of Arabidopsis SNF1 kinase homolog in maize) possessing high sequence similarities (encoded by two gene copies) were identified as interaction partners. Their interactions with P8 were confirmed in both Nicotiana benthamiana cells and maize protoplasts by bimolecular fluorescence complementation assay. The accumulation levels of ZmAKINβγ mRNAs were upregulated at the stage of the viral symptoms beginning to appear and then downregulated. ZmAKINβγs are putative regulatory subunits of the SnRK1 complex, a core regulator for energy homeostasis. Knockdown of ZmAKINβγs in maize regulated the expression levels of the genes involved in sugar synthesis or degradation, and also the contents of both glucose and sucrose. Importantly, downregulation of ZmAKINβγs expressions facilitated the accumulation of RBSDV in maize. These results implicate a role of ZmAKINβγs in the regulation of primary carbohydrate metabolism, and in the defense against RBSDV infection.

Protoplast: A Valuable Toolbox to Investigate Plant Stress Perception and Response

“…The study of protein–protein interaction (PPI) through TEAs in protoplasts can also bring crucial information to decipher kinase signaling in plant cells ( Pecher et al, 2014 ; Cheng et al, 2015 ; Liu et al, 2017 ; Ye et al, 2019 ; Li et al, 2020 ; Takahashi et al, 2020 ), the activation and interaction of TFs ( Pecher et al, 2014 ; Liu et al, 2018 ; Ye et al, 2019 ), or even the interaction between immune receptors and co-receptors ( Halter et al, 2014 ; Yeh et al, 2015 ; Fliegmann et al, 2016 ; Gong et al, 2019 ; Li et al, 2019 ).…”

“…In PCA ( Figure 2C ), one of the studied proteins is fused with the amino-terminal part and the other one with the carboxy-terminal part of a fluorescent protein, such as YFP or mCherry, for BiFC ( Pecher et al, 2014 ; Cheng et al, 2015 ; Li et al, 2020 ) or a luciferase enzyme, such as the firefly luciferase, for SLC ( Chen et al, 2008 ; Cheng et al, 2015 ; Gong et al, 2019 ). In BiFC, when the two proteins interact, the combination of the two parts of the fluorescent protein restores the fluorescence enabling the visualization and the spatial location of protein complexes.…”

A maize lipid droplet-associated protein is modulated by a virus to promote viral multiplication and infection

“…P8 is reported to localize to the nucleus of insect vector and plant cells and repress transcription in tobacco suspension cells (Liu et al, 2007a). Our previous study revealed that P8 interacted with maize AKINβγ, the regulatory subunit of the SNF1-related protein kinase 1 (SnRK1) complex, thus regulating primary carbohydrate metabolism of host plant in response to RBSDV infection (Li et al, 2020). In addition, SP8 encoded by southern rice black-streaked dwarf virus, a closely related fijivirus, was reported to interfere with the dimerization of auxin response factor 17 of rice thus disturbing the auxin signaling pathway and facilitating virus infection (Zhang et al, 2020).…”

Functional analysis revealed the involvement of ZmABCB15 in resistance to rice black-streaked dwarf virus infection

“…Recently, Rad GDP dissociation inhibitor alpha was identified as a host susceptibility factor for RBSDV resistance. βγ subunit of Arabidopsis SNF1 kinase (ZmAKINβγ-1) homolog in maize and ZmAKINβγ-2, two proteins with high sequence similarities, play important roles in the defense against RBSDV infection by regulating the primary carbohydrate, metabolism [ 10 ]. By comparative genomic analysis of the resistant inbred line (X178) and susceptible line (Ye478), Zea mays Eukaryotic Initiation Factor 4E ( ZmeIF4E ) was considered as a candidate gene for MRDD resistance [ 11 ].…”