Cotton leaf curl disease, a multicomponent begomovirus complex

SUMMARY Cotton leaf curl is a serious disease of cotton and several other malvaceous plant species that is transmitted by the whitefly Bemisia tabaci. The disease is, at this time, endemic throughout Pakistan and epidemic in Western India. Affected cotton plants exhibit a range of symptoms such as leaf curling, stunted growth and a poor yield of cotton fibre. In addition, affected plants may develop leaf-like outgrowths from the veins on the undersides of leaves. A number of distinct begomoviruses have been shown to be associated with infected plants, all of which require a satellite component (DNA beta) to induce symptoms in cotton. DNA beta components are a group of recently identified, symptom modulating, single-stranded satellite molecules. An additional, satellite-like component, DNA 1, is invariably found in diseased plants, although it is not required for disease development.