A Bipartite Geminivirus with a Highly Divergent Genomic Organization Identified in Olive Trees May Represent a Novel Evolutionary Direction in the Family Geminiviridae

Patrick Materatski,Mariana Patanita,Maria Do Rosário Félix,Maria Doroteia Campos,António Bento Dias,Susan Jones,Carla M R Varanda

doi:10.3390/v13102035

Patrick Materatski, Mariana Patanita + Show 5 more

Open Access

https://doi.org/10.3390/v13102035

Copy DOI

Journal: Viruses	Publication Date: Oct 9, 2021
Citations: 9	License type: CC BY 4.0

Affiliation: University of Évora, James Hutton Institute

Abstract

Olea europaea Geminivirus (OEGV) was recently identified in olive in Italy through HTS. In this work, we used HTS to show the presence of an OEGV isolate in Portuguese olive trees and suggest the evolution direction of OEGV. The bipartite genome (DNA-A and DNA-B) of the OEGV-PT is similar to Old World begomoviruses in length, but it lacks a pre-coat protein (AV2), which is a typical feature of New World begomoviruses (NW). DNA-A genome organization is closer to NW, containing four ORFs; three in complementary-sense AC1/Rep, AC2/TrAP, AC3/REn and one in virion-sense AV1/CP, but no AC4, typical of begomoviruses. DNA-B comprises two ORFs; MP in virion sense with higher similarity to the tyrosine phosphorylation site of NW, but in opposite sense to begomoviruses; BC1, with no known conserved domains in the complementary sense and no NSP typical of bipartite begomoviruses. Our results show that OEGV presents the longest common region among the begomoviruses, and the TATA box and four replication-associated iterons in a completely new arrangement. We propose two new putative conserved regions for the geminiviruses CP. Lastly, we highlight unique features that may represent a new evolutionary direction for geminiviruses and suggest that OEGV-PT evolution may have occurred from an ancient OW monopartite Begomovirus that lost V2 and C4, gaining functions on cell-to-cell movement by acquiring a DNA-B component.

Highlights

Olive (Olea europaea L.) is one of the most cultivated fruit crops around the world and has significant environmental, social and landscape impact in many countries such as Portugal
We show that Olea europaea Geminivirus (OEGV)-PT presents unique features distinct from other geminiviruses and suggest that OEGV-PT evolution may have occurred from an ancient Old World (OW) monopartite
Contigs >200 bp in length were mapped against viral genomes in Genbank and six contigs mapped to sequences from the Geminiviridae family (Table 1)

Summary

Introduction

Olive (Olea europaea L.) is one of the most cultivated fruit crops around the world and has significant environmental, social and landscape impact in many countries such as Portugal. A common feature of olive viruses is the difficulty of associating viral presence to symptoms. Some authors have associated viral symptoms with chlorosis, defoliation, bumpy fruits, reduction of yield and oil quality [10,11], most viruses, have been recovered from trees without apparent symptoms [7,10,12]. Despite the difficulty in associating viruses to symptoms, many olive viruses are transmitted to other hosts and olive propagative material must be free of viruses for certification and commercialization. For these reasons, studies of the olive virome in different countries is of great economic importance

Methods

Results

Conclusion