Molecular identification of a ‘Candidatus phytoplasma australasia’ related strain associated with French bean phyllody in western India

Abstract

Symptoms such as proliferating branches with shortened internodes and reduced size of leaves, twisting of shoots, virescence and phyllody were observed in French bean crops cultivated in fields near Pune, Maharashtra, India. The DNA extracted from symptomatic plants was amplified by nested PCR using universal primers specific to phytoplasmas. No band was obtained from the healthy plants samples, but all the symptomatic plant samples resulted amplified. The sequence analysis of amplicons revealed that the consensus sequence shared 98–100% identity with phytoplasmas enclosed in 16SrII group, in particular with those infecting legumes in different parts of the world, allowing its identification as a ‘Candidatus Phytoplasma australasia’-related strain. Virtual restriction fragment length polymorphism analysis further confirmed this classification placing the phytoplasma into the 16SrII-D subgroup. This is the first report of a 16SrII-D phytoplasma infecting French bean in India.