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

Mingjun Li,Dianping Di,Aihong Zhang,Zaifeng Fan,Tao Zhou,Xi Sun,Hongqin Miao,Ling Qing

doi:10.3390/v12121387

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.

Highlights

Maize (Zea mays L.) is the most widely grown crop worldwide and is one of the most important food, forage, source of biofuel and other industrial materials [1]
We identified two members of ZmAKINβγ, ZmAKINβγ-1 and ZmAKINβγ-2, in maize, that interact with rice black streaked dwarf virus (RBSDV) P8 in yeast, N. benthamiana and maize protoplasts
To identify the host proteins interacting with RBSDV P8, a yeast two-hybrid screen of a maize cDNA library was performed using the P8 protein fused to the GAL4 DNA binding domain (BD-P8)

Summary

Introduction

Maize (Zea mays L.) is the most widely grown crop worldwide and is one of the most important food, forage, source of biofuel and other industrial materials [1]. Maize rough dwarf disease (MRDD) is a widespread and destructive viral disease worldwide [2,3]. RBSDV is an important and devastating viral pathogen infecting maize, rice, wheat and some other graminaceous hosts, which can be propagatively transmitted by small brown planthopper (Laodelphax striatellus) [7,8]. Maize plants infected by RBSDV exhibit severe growth abnormalities, including plant dwarfing, dark green leaves, and waxy white tumors on sheaths and veins of the abaxial surface of the leaves [9,10]. RBSDV has a double-shelled, icosahedral capsid approximately 75 to 80 nm in diameter and contains 10 segments

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