Identification of phytoplasma strains associated with witches’ broom and yellowing in Ziziphus jujube nurseries in Iran

Ghobad Babaei,Vahid Nikbakht,Mahbobeh Zandian,Seyyed Alireza Esmaeilzadeh-Hosseini

doi:10.36253/phyto-10857

Abstract

Phytoplasma symptoms, including proliferation, witches’ broom, leaf rolling and yellowing, were observed in jujube (Ziziphus jujube) nurseries in the East of Iran. Total nucleic acid was extracted from symptomatic and symptomless plants, and was tested for phytoplasma presence using nested PCR. Amplicons of about 1.8 kb (primer pair P1/P7) and 1.25 kb (R16F2n/R16R2) were obtained from all symptomatic plants but not from symptomless plants. Restriction fragment length polymorphism (RFLP) analysis of R16F2n/R2 amplicons using KpnI, HaeIII, RsaI, AluI, HpaII, HhaI, TaqI, MseI, BfaI and ThaI restriction enzymes showed two RFLP patterns referable to 16SrI and 16SrVI phytoplasma groups. The consensus sequences of Z. jujube yellowing and witches’ broom of six samples correspond to ‘Candidatus Phytoplasma asteris’ and ‘Candidatus Phytoplasma trifolii’-related strains. Two R16F2n/R16R2 16S rDNA sequences representative of each RFLP profile, one each from witches’ broom (accession number MK379605) and yellowing (MK379604) host symptoms, were submitted to the GenBank. Phylogenetic analysis confirmed that the phytoplasma strains associated with jujube yellowing clustered within the 16SrI phytoplasma clade, and those associated with witches’ broom clustered within the 16SrVI clade. Restriction analysis confirmed that virtual RFLP patterns of the jujube yellowing and witches’ broom phytoplasma strains were identical to the reference pattern of 16SrI-B and 16SrVI-A. This is the first report of these phytoplasma strains associations with witches’ broom and yellowing in jujube plants.

Highlights

Jujube (Ziziphus jujube Mill) is a small shrub or tree with small fruits about in the size of date, that is native to southern and central Asia and is grown in the northeast and central parts of Iran
The fruit is used as food, and the plants can be used as a vegetable and for medicinal purposes
This phytoplasma had been described as ‘Candidatus Phytoplasma ziziphi’ (Jung et al, 2003), and it is transmitted by the leafhoppers Hishimonoides chinensis and H. sellatus (La and Woo, 1980)

Summary

Introduction

Jujube (Ziziphus jujube Mill) is a small shrub or tree with small fruits about in the size of date, that is native to southern and central Asia and is grown in the northeast and central parts of Iran. Jujube witches’ broom (JWB) was first reported as a graft transmissible disease (Kim, 1965), as phyllody, lack of fruit production and dieback in China (La and Woo, 1980). Phytoplasma agents associated with JWB belong to subgroup 16SrV-B, and showed the same 16S ribosomal sequence in China and Korean strains (Zhu et al, 1998; Han and Cha, 2002). This phytoplasma had been described as ‘Candidatus Phytoplasma ziziphi’ (Jung et al, 2003), and it is transmitted by the leafhoppers Hishimonoides chinensis and H. sellatus (La and Woo, 1980). Mixed infections of jujube by two phytoplasmas of groups of 16SrI and 16SrV-B were reported in Korea (Lee et al, 2009)

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