the Lethal Yellowing Type Diseases

(1)

Overview of

the Lethal Yellowing Type Diseases

Diversity, variability and diagnosis of Cape St Paul Wilt of coconut

**Michel Dollet, Robert Quaicoe¤, Vera Marinho , Fabian Pilet

* UPR 29 CIRAD, ¤ OPRI, ** EMBRAPA

(2)

First symptom : All the nuts fall

LY Diseases:

a syndrome

(3)

Second stage : yellowing of the lower leaves

(4)

Browning, necrosis of the rachillas (opened inflorescence)

(5)

Necrosis of male flowers - non opened inflorescence

(6)

Yellowing of upper leaves

Quintana Roo, Mexico Cabo Delgado, Mozambique

(7)

LYTD,final stage

Lethal Yellowing Type Syndrome

LYTS

Cabo Delgado, Mozambique 2007

(8)

Consequences of the LYTS Axim, Ghana 2007

(9)

Consequence of a long period of drought (A. Mpunami & J.Mugini )

North Tanzania 2006-2007

(10)

Another LYTS: Hartrot (Guiana)

(11)

In Latin America – Caribbean, possible confusion with

:

Hartrot (Trypanosomatids) Red ring (Nematodes)

(12)

Distribution of the Lethal Yellowing Type Syndrome in Africa 1930s

Benin?

1905 or before

Coconut only

(13)

Mexico

Distribution of the LY in the Caribbean since 1890s

80s

2006

XIX century

Several palm species

(14)

Caribbean

« Lethal Yellowing »

Beakbane et al. 1972

Plavsic-Banjac et al. 1972

Kaincopé disease (Togo) Cape St Paul Wilt (Ghana)

Dollet et al. 1976 Dabeck et al. 1976

Kribi disease (Cameroon)

Dollet et al. 1977

Africa

Lethal Yellowing Type Syndromes, associated with phytoplasmas (MLO)

(15)

Phytopl .

Plant Host

Vector

Season

Temp. Hum.

Flora Fauna

Cultural

Pratices Geography

Relief Associated .Cultures

Phytoplasma system

(16)

9 Phytoplasma : 28 "16S rDNA groups"

- Genus?

- Species?

9 "Subgroups"

Example : 16S rDNA I

- 11 Species?... or

- 11 Sub-species?

(17)

16S 23S

5’ 3’

tRNA^Ile

P1 P7

P1/P7

G813/AKSR

1800 pb

892pb

Diagnosis of LYTS by PCR using ribosomal operon

Other « specific primers » :

« LY-F / LY-R » (Florida)

« Rohde’s primers » (Tanzania) AKSR

G813

CSPWD Primers

(18)

LD Tanzania

LY Florida

LY Nigeria

LY Ghana (CSPWD)

Lethal Yellows Group ? Or

Coconut Group ?

Yucatan decline

Current position of the LYTS phytoplasmas in the 16S rDNA groups

16S rDNA

Tymon et al. 1998

(19)

MW 1 2 3 4 5 6 7 8 9 10 11

Heteroduplex Mobility Assay analysis ^(HMA)

PCR-amplified : 16S/23S rDNA

G = Ghana

Mz = Mozambique T= Tanzania

Mx = Mexico C = Cuba

J = Jamaica

G Mz

T Mx C J ^ϕ

(20)

Variability inside the 16S and 5’ end of 23S in Africa

G : variability inside Ghana isolates

M : variability inside Mozambique isolates

M/G : variability between Mozambique and Ghana isolates

Explanation for false negative

(21)

New primer ^{: GAKSR}

CSPW and Mozambique LY variability

Improvement of the diagnosis

AKSR : TTGAATAAGAGGAATGTGG

GAKSR : TTGAATAAGAGGAATATGG

(22)

PCR- rpF1 / rpR1

Other genes under studies for diagnosis and variability

rp (ribosomal proteins)

tuf

Gro EL

Amp

secA, secE, secY

…

(23)

CONCLUSIONS

9

There is not ONE coconut disease called « Lethal Yellowing »,

but SEVERAL Lethal Yellowing Type Syndroms in the Carribean,

in Latin America and in Africa.

(24)

CONCLUSIONS

9

There is not ONE coconut disease called « lethal yellowing », but SEVERAL Lethal Yellowing Type Syndroms in the Carribean, Latin America and in Africa.

9 There are at least 6 different phytoplasmas associated with these LYTS

(25)

CONCLUSIONS

9

There is not ONE coconut disease called « lethal yellowing », but SEVERAL Lethal Yellowing Type Syndroms in the Carribean, Latin America and in Africa.

9

Inside Ghana and Mozambique isolates (same subgroup)

there is a variability

(26)

CONCLUSIONS

9

There is not ONE coconut disease called « lethal yellowing », but SEVERAL Lethal Yellowing Type Syndroms in the Carribean, Latin America and in Africa.

the Lethal Yellowing Type Diseases

Overview of