Host range and population structure of pv.

(1)

Host range and population structure of

Xanthomonas citri

pv.

mangiferaeindicae

Gagnevin L, Guérin F, Vital K, Deloison G, Pruvost O

UMR PVBMT

CIRAD-Université de la Réunion France

There are two types of strains in pv.

mangiferaeindicae

• isolated from mango (Mangifera indica)

• pathogenic on mango

• weakly pathogenic on pepper tree

• isolated on pepper tree (Schinus terebinthifolius)

• pathogenic on pepper tree

• weakly pathogenic on mango

No other characteristic or genetic marker can differenciate them and allow to com-pare them

Populations coexist, almost in a sympatric manner with the two hosts often adjacent

Minisatellites derived from

X. c.

pv.

citri

to characterize

mangiferaeindicae

populations

12 loci identified based on the complete sequence of strain FDC12 using the web tool http://minisatellites.u-psud.fr

• containing repeats of 6 or 7 nucleotides

• primers designed for production of amplicons of 150 to 450 bp

• genome-wide localization

Minisatellite processing is multiplexable for amplification and automated electrophoresis

Analysis of 6 populations from the 2 hosts

179 isolates from 3 sites containing mango trees and pepper trees, considered as 6 populations :

1999 2009 2009

Bassin Martin/Mango (BM/M) Bassin Plat/Mango (BP/M) Grand Fond/Mango (GF/M) Bassin Martin/Pepper tree (BM/P) Bassin Plat/Pepper tree (BP/P) Grand Fond/Pepper tree (GF/P)

• two minisatellites are monomorphic for all populations

• some are polymorphic only within one or a few populations

• most are polymorphic between and within populations

• 81 haplotypes were differenciated

• no haplotype was common to different populations

Questions

• What are the evolutionary and epidemiological relationships between these populations ?

• What tools may help to describe evolution at a very small geographic and probably time scale ? • Can this example help to understand host

shif-ting in xanthomonads ? Differentiation coefficients BM/P BP/P GF/P BM/M BP/M GF/M BM/P 0 BP/P 0.35 0 GF/P 0.17 0.32 0 BM/M 0.53 0.67 0.48 0 BP/M 0.38 0.51 0.35 0.37 0 GF/M 0.29 0.45 0.28 0.32 0.18 0

0.29

BM GF BP BM BP GF H12 (7) H47 (1) H44 (1) H50 (1) H48 (1) H40 (1) H49 (1) H45 (1) H13 (2) H41 (1) H6 (2) H5 (6) H4 (11) H77 (1) H79 (1) H8 (2) H7 (2) H80 (1) H1 (12M) H34 (1) H3 (2) H2 (2) H75 (1) H33 (5) H42 (1) H32 (3) H81 (1) H9 (3) H11 (2) H76 (1) H43 (1) H78 (1) H10 (2) H51 (1) H46 (1) H15 (9) H19 (5) H20 (3) H72 (1) H63 (1) H17 (2) H70 (1) H69 (1) H71 (1) H21 (3) H74 (1) H64 (1) H67 (1) H18 (2) H16 (3) H65 (1) H62 (1) H27 (4) H28 (2) H60 (1) H53 (1) H52 (1) H73 (1) H68 (1) H25 (8) H39 (1) H26 (2) H61 (1) H59 (1) H36 (1) H35 (1) H24 (5) H30 (3) H31 (2) H22 (2) H23 (7) H56 (1) H14 (2) H55 (1) H58 (1) H57 (1) H66 (1) H54 (1) H38 (1) H37 (1) H29 (2) Mango Pepper tree 1.0

pepper tree isolates mango isolates

other isolates GF in 1996

Mango

Pepper tree

unweighted neighbour joining tree based on a distance of Manhattan (assuming a step by step evolution)

clonal complexes (evolutionally and epidemiologically related haploty-pes) constructed based on continuous variations of less than 3 repeats, indicating potential primary and secondary founders

Host range and population structure of pv.