Detection and molecular characterization of phytoplasma associated with Hibiscus Witches-Broom in Egypt
Detection and molecular characterization of phytoplasma associated with Hibiscus Witches-Broom in Egypt
Mokbel, Samah A.1,Ahmed K. El Attar1; Azza G.Farag2.
ABSTRACT
Hibiscusrosa-sinensisis a valuable ornamental species widely planted in Egypt. The
Phytoplasma associated witches‟-Broom has been detected on symptomatic hibiscus
plants. Samples of hibiscusleaves were collected from El Giza, Alexandria, Qlubia,El-
Fayom, and El-Mansouragovernoratesand analyzed for phytoplasma infection.The
collected hibiscus plants showed characteristic symptoms for Phytoplasma associated
witches‟-Broom disease, which is characterized by excessive axillary branching,
abnormally small leaves, and deformed flowers. Dienes‟ stain was used for detection of
witches‟ broom infection midribs of the symptomatichibiscus plant. The phloem of
infected tissues showed scattered area stained bright blue. Molecular detection utilizing
nested and direct PCR as well as DNA sequencing was used for the diagnosis of the
witches‟ Broom infection. Total DNA was isolated from leaf tissues of infected hibiscus
plants. Nestedpolymerase chain reaction(PCR) was performed using the universal -
phytoplasma specific primers; P1/P7, R16F2n/R16R2.Witches‟ broom specific primers
SR1/ SR2, at the spacer region (SR), were used for the direct PCR. Amplicons of
expected size characteristic for phytoplasma associated witches‟ broom were obtained
from infected hibiscus samples. DNA sequencing and phylogenetic analysis of the 16S
rRNA gene fragment from the hibiscus witches' broom phytoplasma showed 100%
homology with the same region of thehibiscus witches' broom strain thatisolatedin Brazil
(PhytoplasmaBrasiliense). The DNA sequence was submitted for the gene bank as the
first report of the Brasiliensephytoplasma associated witches‟ broom affecting hibiscus in
Egypt.
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December 2013
Vol. 10, Pages 1-171
