Ageratum enation virus—A Begomovirus of Weeds with the Potential to Infect Crops

Abstract

Samples of two Ageratum conyzoides, one Sonchus oleraceus and one turnip (Brassica rapa var. rapa) exhibiting virus-like symptoms were collected from Pakistan and Nepal. Full-length begomovirus clones were obtained from the four plant samples and betasatellite clones from three of these. The begomovirus sequences were shown to be isolates of Ageratum enation virus (AEV) with greater than 89.1% nucleotide sequence identity to the 26 AEV sequences available in the databases. The three betasatellite sequences were shown to be isolates of Ageratum yellow leaf curl betasatellite (AYLCB) with greater than 90% identity to the 18 AYLCB sequences available in the databases. The AEV sequences were shown to fall into two distinct strains, for which the names Nepal (consisting of isolates from Nepal, India, and Pakistan—including the isolates identified here) and India (isolates occurring only in India) strains are proposed. For the clones obtained from two AEV isolates, with their AYLCB, infectivity was shown by Agrobacterium-mediated inoculation to Nicotiana benthamiana, N. tabacum, Solanum lycopersicon and A. conyzoides. N. benthamiana plants infected with AEV alone or betasatellite alone showed no symptoms. N. benthamiana plants infected with AEV with its associated betasatellite showed leaf curl symptoms. The findings show that AEV is predominantly a virus of weeds that has the capacity to infect crops. AYLCB appears to be the common partner betasatellite of AEV and is associated with diseases with a range of very different symptoms in the same plant species. The inability to satisfy Koch’s postulates with the cloned components of isolate SOL in A. conyzoides suggests that the etiology may be more complex than a single virus with a single betasatellite.

High-Throughput Sequencing Reveals Differential Begomovirus Species Diversity in Non-Cultivated Plants in Northern-Pacific Mexico

“…The ecology of begomoviruses identified by HTS studies in non-cultivated plants requires more effort in order to understand the contribution of these plants for disease development [74,75,76]. Non-cultivated plants could be a source of viral inoculum to cultivated plants [77,78,79,80,81,82,83] and could contribute to viral evolution. Here, we described some non-cultivated plants at the agro-ecological interface carrying geminivirus-signatures (Table 3 and Supplementary Table S2).…”

Ageratum enation virus Infection Induces Programmed Cell Death and Alters Metabolite Biosynthesis in Papaver somniferum

“…Ageratum enation virus and associated satellite DNAs (ALCB and ALCA) were originally discovered from a weed plant, A. conyzoides ( Tahir et al, 2015 ). Now, AEV is emerging as a devastating pathogen in India and reported to cause significant losses in many crops ( Kumar et al, 2013 ; Srivastava et al, 2013 ; Swarnalatha et al, 2013 ).…”

Identification of a monopartite begomovirus associated with yellow vein mosaic of Mentha longifolia in Saudi Arabia

“…It is well recognized that genetic recombination plays a significant role in the diversification and evolution of Geminiviruses. Recombination has been documented to occur between geminivirus, between betasatellites, alphasatellites and between helper viruses and betasatellites (Ajlan and Ghanem 2007;Duffy and Holmes 2008;Khan et al 2008;Nawaz-ul-Rehman and Fauquet 2009;Lefeuvre et al 2010;Paprotka and Jeske 2010;Sivalingam et al 2010;Idris et al 2011Idris et al , 2012Huang et al 2013;Al-Saleh et al 2014a, b;Hosseinzadeh et al 2014;Kenyon et al 2014;Khan et al 2014;Paz-Carrasco et al 2014;Yang et al 2014;Tahir et al 2015;Sohrab 2016Sohrab , 2017Al Rwahnih et al 2017). The natural infection of TYLCV in M. longifolia showed the gradual increase of begomovirus host range which may cause heavy economic losses to the other cultivated as well as medicinal and weed crops in the near future in the Kingdom.…”