Identification of phytoplasmas associated with weed species in India

摘要

Suspected phytoplasma symptoms of typical leaf chlorosis, witches' broom and little leaf were recorded on sixteen weed species in and around agricultural fields in different parts of India during 2013 and 2014. The symptomatic weed species were analyzed for phytoplasma association through nested PCR assays by utilizing universal phytoplasma specific primer pairs, P1/P6 and R16F2n/R16R2. Out of sixteen symptomatic weed species collected, ten weed species, viz. Digitaria ciliaris. Phalaris minor, Eleusine indica, Cynodon dactylon, Parthenium hysterophorus, Dichanthium annulatum, Cannabis sativa, Datura stramonium, Digitaria sanguinalisand Oplismenus burmanniiwere found positive for phytoplasmas. pairwise sequence and phylogenetic analysis of the 1.2 kb products of 16S rDNA phytoplasma sequences of ten positive weed species confirmed association of three different groups of phytoplasmas, viz. 16Srl, 16Srll and 16SrXIV. Reports of phytoplasma association with D. ciliaris (16SrXIV group), E. indica (16SrXI V group) and P. minor (A 6Srl group) were the new records of phytoplasma hosts in the world. However, the two weeds, viz. P. hysterophorus and O. burmannii were reported as hosts for the new phytoplasma group (16Srll) in India.