A VIGS screen identifies immunity in the Arabidopsis Pla-1 accession to viruses in two different genera of the Geminiviridae.

Maria Ines Reyes,Cyprian Rajabu,Orlene Guerra‐Peraza,Linda Hanley‐Bowdoin,Yokiko H Hiromoto‐Ruiz,Miguel A Flores‐Vergara,Susanne Kjemtrup,Jigar Desai,Joseph Ndunguru,Dominique Robertson,Jose T Ascencio‐Ibáñez

doi:10.1111/tpj.13716

Abstract

SummaryGeminiviruses are DNA viruses that cause severe crop losses in different parts of the world, and there is a need for genetic sources of resistance to help combat them. Arabidopsis has been used as a source for virus‐resistant genes that derive from alterations in essential host factors. We used a virus‐induced gene silencing (VIGS) vector derived from the geminivirus Cabbage leaf curl virus (CaLCuV) to assess natural variation in virus–host interactions in 190 Arabidopsis accessions. Silencing of CH‐42, encoding a protein needed to make chlorophyll, was used as a visible marker to discriminate asymptomatic accessions from those showing resistance. There was a wide range in symptom severity and extent of silencing in different accessions, but two correlations could be made. Lines with severe symptoms uniformly lacked extensive VIGS, and lines that showed attenuated symptoms over time (recovery) showed a concomitant increase in the extent of VIGS. One accession, Pla‐1, lacked both symptoms and silencing, and was immune to wild‐type infectious clones corresponding to CaLCuV or Beet curly top virus (BCTV), which are classified in different genera in the Geminiviridae. It also showed resistance to the agronomically important Tomato yellow leaf curl virus (TYLCV). Quantitative trait locus mapping of a Pla‐1 X Col‐0 F2 population was used to detect a major peak on chromosome 1, which is designated gip‐1 (geminivirus immunity Pla‐1‐1). The recessive nature of resistance to CaLCuV and the lack of obvious candidate genes near the gip‐1 locus suggest that a novel resistance gene(s) confers immunity.

Highlights

The Geminiviridae is a large family of circular, singlestranded DNA plant viruses named for their twinned particles (Hanley-Bowdoin et al, 2013)
(Turnage et al, 2002), we showed that Col-0 plants inoculated with a virus-induced gene silencing (VIGS) vector derived from the geminivirus Cabbage leaf curl virus (CaLCuV) carrying a fragment of the CH-42 gene
We conducted a screen of Arabidopsis accessions to assess natural variation in response to a geminivirus VIGS vector

Summary

Introduction

The Geminiviridae is a large family of circular, singlestranded DNA (ssDNA) plant viruses named for their twinned particles (Hanley-Bowdoin et al, 2013) They are classified into different genera depending on their insect vector, genome structure and host range (Hanley-Bowdoin et al, 2013; Varsani et al, 2014). Geminiviruses infect a broad range of crop plants primarily in tropical and subtropical regions of the world (Moffat, 1999) Their incidence and severity have increased over the past 20 years (Mansoor et al, 2006; Navas-Castillo et al, 2011), and some resistance strategies used to control them are no longer effective. Variations in the first gene, Ty-1/Ty-3, which encodes a

Results

Discussion

Conclusion