Establishing RNA virus resistance in plants by harnessing CRISPR immune system

Abstract

SummaryRecently, CRISPR‐Cas (clustered, regularly interspaced short palindromic repeats–CRISPR‐associated proteins) system has been used to produce plants resistant to DNA virus infections. However, there is no RNA virus control method in plants that uses CRISPR‐Cas system to target the viral genome directly. Here, we reprogrammed the CRISPR‐Cas9 system from Francisella novicida to confer molecular immunity against RNA viruses in Nicotiana benthamiana and Arabidopsis plants. Plants expressing FnCas9 and sgRNA specific for the cucumber mosaic virus (CMV) or tobacco mosaic virus (TMV) exhibited significantly attenuated virus infection symptoms and reduced viral RNA accumulation. Furthermore, in the transgenic virus‐targeting plants, the resistance was inheritable and the progenies showed significantly less virus accumulation. These data reveal that the CRISPR/Cas9 system can be used to produce plant that stable resistant to RNA viruses, thereby broadening the use of such technology for virus control in agricultural field.

CRISPR-Cas13d mediates robust RNA virus interference in plants

“…Previous studies harnessing CRISPR-Cas proteins, such as FnCas9 from Francisella novicia, to target RNA viruses have shown that the binding, but not the cleavage, ability of these proteins is sufficient to inhibit virus replication in mammalian and plant cells [45,49]. Our data show that the HEPN-dependent catalytic activity of CasRx is essential for efficient virus interference, which in turn indicate that the observed CasRxmediated virus interference results from targeted viral genomic degradation.…”

Establishing CRISPR/Cas13a immune system conferring RNA virus resistance in both dicot and monocot plants

“…However, through long-term co-evolution, eukaryotic viruses have developed methods of antagonize RNAi, which limited the applications in agriculture. In recent years, the CRISPR/Cas9 machinery has been exploited to combat eukaryotic viruses in dicot plants (Ali et al, 2015;Aman et al, 2018;Baltes et al, 2015;Ji et al, 2015;Zhang et al, 2018). To our knowledge, this is the first report of a method targeting the viral RNA to control viral diseases in monocot plants.…”

“…Dear Editor, Besides its powerful capability for genome editing, the clustered, regularly interspaced short palindromic repeats (CRISPR)/CRISPRassociated (Cas) (CRISPR/Cas) systems, has been exploited to combat virus infection in eukaryotic organisms (Zaidi et al, 2016). By harnessing CRISPR/Cas system, its compelling inhibiting activities against DNA viruses (Ali et al, 2015;Baltes et al, 2015;Ji et al, 2015) or RNA viruses (Aman et al, 2018;Zhang et al, 2018) were reported in many cases. Moreover, due to the facts that the eukaryotic viruses themselves do not equip the ability to counter this prokaryotic immune defense, by utilization of such strategy, we could establish effective control and eradiation strategy against the eukaryotic virus.…”

“…RNA viruses cause serious losses in crops and significant damage to agricultural production, and there are two types of CRISPR/Cas effectors, Cas9 from Francisella novicida (FnCas9) and Cas13a from Leptotrichia shahii (LshCas13a) or Leptotrichia wadei (LwaCas13a), have been introduced to target RNA in vivo (Abudayyeh et al, 2016;Sampson et al, 2013). Previously we have successfully established FnCas9 immune system conferring RNA virus in tobacco and Arabidopsis (Zhang et al, 2018), in this study, we reprogrammed and expressed the LshCas13a system in plants, and employed several RNA viruses to test the antivirus effect of the CRISPR/Cas13a system from L. shahii. Our study demonstrates this system can target and degrade viral RNA genomes, and confer resistance to RNA viral diseases in monocot grain plants.…”

“…To our knowledge, this is the first report of a method targeting the viral RNA to control viral diseases in monocot plants. In addition, we have used two distinct type of CRISPR/Cas system, Cas9 from F. novicida (Zhang et al, 2018) and Cas13a from L. shahii (this study), both of them showed high efficiency in generating RNA virus-resistant plants. The difference is that the former depends on FnCas9 binding viral RNA, while the latter requires LshCas13a having RNases activity to cleave viral RNA.…”