Molecular Characterization and Phylogeny of a Phytoplasma Associated with Phyllody Disease of toria (Brassica rapa L. subsp. dichotoma (Roxb.)) in India

Abstract

Samples from toria plants (Brassica rapa L. subsp. dichotoma (Roxb.)) exhibiting phyllody, virescence, witches broom, extensive malformation of floral parts, formation of bladder like siliquae and flower sterility were collected from four different locations in India. Sequencing and phylogenetic analysis of the 16S rRNA, a part of 23S rRNA, partial sec A genes, rp gene and 16S-23S intergenic spacer region indicated that the phytoplasmas associated with toria phyllody (TP) symptoms were identical and belonged to 16SrIX phytoplasma Pigeon pea witches'-broom (PPWB) group. The iPhyClassifier generated virtual RFLP pattern of 1.25 kb 16S rDNA sequences indicated that TP phytoplasma belongs to 16SrIX-C phytoplasma subgroup. Complete 23S rRNA gene of TP phytoplasma had 2,787 nucleotides and is the first sequence of 16SrIX phytoplasma group. Restriction digestion of 16S rDNA and 23S rDNA PCR products has also shown that TP phytoplasmas from all the four locations in India were identical. Toria is a previously unreported host for a phytoplasma in16SrIX-C subgroup.

Diseases of Edible Oilseed Crops

“…toria), and yellow sarson (B. rapa var. yellow sarson) in the states of Punjab, Haryana, New Delhi, and Uttar Pradesh (Kolte 1985, Azadvar andBaranwal 2010) in India. In Canada, aster yellows (AY) has also been reported on B. napus and B. rapa (Olivier et al 2010).…”

“…The phyllody disease is reported to be caused by the Candidatus Phytoplasma asteris (Phytoplasma asteris) phytoplasma of subgroup 16Srl-A, 16Srl-B, and 16SrlX-C , Maliogka et al 2009, Azadvar and Baranwal 2010, Rampin et al 2010, Zwolinska et al 2011. The AY disease is reported to be caused by the phytoplasma of 16Srl-A and 16Srl-B subgroup (Olivier et al 2010).…”

“…Phytoplasma are nonhelical, mycoplasma-like bacteria that lack cell walls. They almost exclusively inhabit the phloem sieve-tube elements of the infected plant and is transmitted from plant to plant by phloem-feeding homopteran insects mainly plant hoppers (Laodelphax striatellus) (Azadvar and Baranwal 2010) or leafhoppers (Circulifer haematoceps) (Salehi et al 2011), and less frequently psyllids and Cicadellidae (Jajor 2007). Seed transmission of phytoplasma in winter oilseed rape has also been reported (Calari et al 2011).…”

“…This pathogen can be detected by several methods, namely, nested PCR , Azadvar et al 2011, Calari et al 2011, PCR, and RFLP Hiruki 2001, Zwolinska et al 2011). Sequencing and phylogenetic analysis of 16S rRNA, a part of 23S rRNA, partial sec A genes, rp gene and 16S-23S intergenic spacer region, and RFLP pattern of 1.25 kb 16S rDNA sequences of the pathogen has also been done (Azadvar and Baranwal 2010).…”

Molecular detection and characterization of phytoplasma associated with China aster (Callistephus chinensis) phyllody in India

“…Result similar to the present investigation has already proposed by Win et al (2011) indicated that China aster as a new host for a subgroup 16SrII-A phytoplasma. The 16S rDNA gene has not been sequenced completely for most of the phytoplasmas (Azadvar and Baranwal, 2010). Whether rDNA gene, encoding 16S can be used for finer differentiation of phytoplasmas in a group or not will be known when more sequences of phytoplasma in a group become available.…”