Martinez RT, Narvaez M, Fabre S, Harrison N, Oropeza C,^ Dollet M and
Hichez E (2007). Coconut lethal yellowing on the Southern Coast of the
Dominican Republic is associated with a new 16Sr IV group phytoplasma.
New Disease Reports. http://www.bspp.org.uk/ndr/volume15.asp
Coconut palm (Cocos nucifera.) is an important economic and landscape
crop in the Dominican Republic. Lethal yellowing (LY), a phytoplasma
disease of coconut palm, was first reported in the northern coastal
provinces of Puerto Plata, Santiago, Dajabon and Luperon in 1962
(Pujals Nolasco & Hichez Frias, 1974). No further spread of LY was
reported during 1969 to 1986, which is attributed to quarantine and
eradication programs in the affected provinces but natural barriers
e.g. topography, edaphic factors, and an abundance of non-host palms
could also have contributed (Harries et al., 2001).
Figure 1: Hinf I (A) and Alu I (B) endonuclease digests of phytoplasma
rDNA products amplified by nested PCR from coconut palms affected by
lethal yellowing on the southern coast of the Dominican Republic and
in Yucatan, Mexico. M is DNA ladder.
Dead or dying coconut palms with symptoms of LY were first recognized
at Boca Chica on the southern coast during February 2006. Leaf,
inflorescence or trunk tissues from five diseased palms were tested
for phytoplasma infection using a nested PCR with primers P1/P7
followed by LY group-specific primers LY16Sf/LY16Sr (Harrison et al.,
2002). A product (1.39 kb) was amplified from all five affected palms
but not from a symptomless coconut palm. AluI or HinfI endonuclease
digests of nested PCR products showed no differences in fragment
patterns amongst the five diseased palms (Fig. 1). However, these
patterns were atypical of the LY phytoplasma belonging to the 16SrIV-A
subgroup (Lee et al., 1998). Comparison of near full-length 16S rRNA
gene sequence obtained after amplification with primers P1/P7 (GenBank
accession No. DQ631639), indicated this phytoplasma was most similar
(99.9%) to the strain associated with Yucatan coconut lethal decline
(LDY) (U18753), a subgroup 16SrIV-B member (Lee et al., 1998), but
belonging to a newly identified subgroup, 16SrIV-E, while sharing only
98.3% identity with LY phytoplasma (AF498308, AF498309).
This is the first report of a new 16SrIV group phytoplasma associated
with yellowing coconut palms in Dominican Republic.
This study was partially funded by the Common Fund for Commodities,
Stadhouderskade 1072 AB Amsterdam (FIGOOF/22).
Harries HC, Herasme CJ, Hichez-Frias E, 2001. Why lethal yellowing has
not become epidemic in the Dominican Republic. Palms 45, 92-96.
Harrison NA, Womack M, Carpio ML, 2002. Detection and characterization
of a lethal yellowing (16SrIV) group phytoplasma in Canary Island date
palms affected by lethal decline in Texas. Plant Disease 86, 676-81.
Lee I.-M, Gundersen-Rindal DE, Davis RE, Bartoszyk IM, 1998. Revised
classification scheme of phytoplasmas based on RFLP analyses of 16S
rRNA and ribosomal protein gene sequences. International Journal of
Systematic Bacteriology 48, 1153-69.
Pujals Nolasco JP, Hichez Frias E, 1974. Informe sobre la situación
del amarillo letal en las plantaciones de cocoteros en áreas de la
República Dominicana. Secretaria de Estado de Agricultura, Santo
Domingo, República Dominicana.