A Single Species of Betasatellite is Prevalent in Chilli across North Central Pakistan and Shows Phylogeographic Segregation

Abstract

Chilli leaf curl disease is an important constraint to production of chilli peppers (Capsicum annum L.) across the Indian subcontinent and is caused by begomoviruses in association with betasatellites. Betasatellites are symptom modulating single-stranded DNA satellites associated with the majority of monopartite begomoviruses and are responsible for diseases of many crops including chilli peppers. Here, we have studied the diversity of a betasatellite of chillies in the Punjab and North Western Frontier Province of Pakistan. Sequence analysis of thirteen full-length clones showed that a single species of satellite, Chilli leaf curl betasatellite (ChLCB), is prevalent in chilli throughout the surveyed region. ChLCB has only been identified in Pakistan and infecting chilli. It thus probably represents a chilli adapted satellite. The ChLCBs fall into two groups, the first occurs in the less intensively cultivated north and shows a high level of sequence diversity (relative to the second group), while the second occurs in the southern cotton-growing areas and shows little sequence diversity. Between these two areas there is a region of overlap where both ChLCB types occur. The phylogeographic segregation of ChLCB we attribute to geographic isolation (in the north), leading to divergence and intensive cultivation (in the south), leading to homogenization. However, the lack of diversity (only a single species) bodes well for the prospects of achieving resistance to the disease by either conventional or pathogen-derived strategies.

Virus–vector Relationships, Host Range, Detection and Sequence Comparison of Chilli leaf curl virus Associated with an Epidemic of Leaf Curl Disease of Chilli in Jodhpur, India

“…In our study and a previous study (Chattopadhyay et al. 2008), ToLCBDB was found to be associated with the chilli leaf curl disease in India, whereas in Pakistan ChLCB was reported from chilli leaf curl (Hussain et al. 2009; Tahira et al.…”

Genetic diversity and distribution of a distinct strain of Chili leaf curl virus and associated betasatellite infecting tomato and pepper in Oman

“…In Capsicum spp. numerous other betasatellites are reported to be associated with begomovirus diseases, of which the major one in Pakistan is chili leaf curl betasatellite (Hussain et al, 2009). It is thus somewhat surprising to find ToLCB associated with a disease of tomato and, particularly, chili and also surprising that of the numerous betasatellites associated with diseases of tomato and chili on the Indian sub-continent only one, ToLCB, was introduced into Oman.…”

Both malvaceous and non-malvaceous betasatellites are associated with two wild cotton species grown under field conditions in Pakistan

“…The betasatellite-encoded bC1 protein is a disease-specific symptom determinant and for the CLCuD-associated CLCuMB has been shown to be able to induce all symptoms typical of the disease [19]. Leaf curl disease of chillies is associated with a diseasespecific betasatellite, Chilli leaf curl betasatellite (ChLCB) [14,16]. Although generally betasatellites that infect malvaceous plant species have been identified in nonmalvaceous hosts, betasatellites of non-malvaceous plants do not occur in malvaceous hosts.…”