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• Plant genomes contain sequences of viruses with dsDNA (Caulimoviridae) and ssDNA (Geminiviridae) genomes which have

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Jean-Philippe Pichaut1, Benoît Farinas1, Marie Umber1, Matthieu Chabannes2, Nathalie Laboureau2, Pierre Olivier Duroy2, Lydiane Bonheur1, Frédéric Salmon1, Christophe Jenny1,

Marie-Line Iskra-Caruana2 & Pierre-Yves Teycheney1 Marie-Line Iskra-Caruana2 & Pierre-Yves Teycheney1

1 CIRAD, UMR AGAP, F-97130 Capesterre Belle-Eau, Guadeloupe, France

2 CIRAD, UMR BGPI, F-34398 Montpellier Cedex 5, France

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Horizontal gene transfer is a very important process in eukaryotic evolution and viruses are prominent DNA donors

Plant genomes contain sequences of viruses with dsDNA (Caulimoviridae) and ssDNA (Geminiviridae) genomes which have

Animal genomes contain retroviruses and LTR retrotransposons

(Caulimoviridae) and ssDNA (Geminiviridae) genomes which have no obligatory integration step in their replication cycle.

Teycheney P-Y & Geering ADW (2011) Endogenous viral sequences in plant genomes. Recent Advances in Plant Virology, eds Caranta C, Aranda MA, Tepfer M, & Lopez- Moya JJ (Caister Academic Press), pp 347-366.

Some endogenous Caulimoviridae sequences of banana, petunia

and Nicotiana edwardsonii are infectious and can lead to the

release of viral particles through stress-induced activation.

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Musa acuminata (A) Musa balbisiana (B)

Fruit organoleptic qualities

• Disease resistance traits

Rusticity and robustness

Partial or total resistance to

biotic and abiotic stresses

(4)

Interspecific hybrid

Infectious eBSV integrated into the genome of the M.

balbisiana parent

Activating stress

Viral particles

© J. Vo, QAAFI

Dallot S., Acuna P., Rivera C., Ramirez P., Côte F., Lockhart B.E.L., Caruana M.L. (2001). Archives of virology, 146: 2179-2190.

Lheureux F., Carreel F., Jenny C., Lockhart B.E.L., Iskra Caruana M.L. (2003). Theoretical and applied genetics, 106 : 594-598 Côte F, Galzi S., Folliot M., Lamagnère Y., Teycheney P.-Y., Iskra-Caruana M.-L. (2010). Mol. Plant Pathol.11: 137–144

Interspecific hybrid (AAB / AAAB)

Known activating stresses:

interspecific crosses

temperature differences

micropropagation

Viral particles Risk of

outbreak

(5)

Yellow leaf streaks Pseudostem splitting

Abnormal

inflorescence and bunch emergence

(6)

• Improved banana hybrid varieties with disease resistance traits are the key to increased sustainability through the reduction of pesticide usage

• Breeding strategies rely on a narrow genetic basis, and only on 2 families of progenitors : Musa acuminata (A) and Musa balbisiana (B)

AAw x AAcv colchicine

AAcv AAAAcv

• CIRAD’s breeding scheme:

AAcv AAAAcv

AAcv x AAcv

colchicine

AAcv x BBw ABcv AABBcv

AAcv x AAAAcv AAAcv

AAw x AAAAcv AAAcv

BBw x AAAAcv AABcv

AAcv x AABBcv AABcv

AAw x AABBcv AABcv

Tetraploid parents

Triploid hybrids

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Tetraploid parents

AAw x AAcv colchicine

AAcv AAAAcv

AAcv x AAcv

colchicine

AAcv x BBw ABcv AABBcv

Triploid hybrids

AAcv x AAAAcv AAAcv

AAw x AAAAcv AAAcv

BBw x AAAAcv AABcv

AAcv x AABBcv AABcv

AAw x AABBcv AABcv

• Only M. acuminata progenitors are used since 2001, which narrows down the genetic basis available for breeding new varieties

• Research efforts have been focused on the creation of M. balbisiana ressources

devoid of infectious eBSVs for breeding purposes

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eBSGFV-7

(BAC 71C19)

eBSGFV-9

(BAC 94I16)

13.3 kb

15.6 kb

eBSOlV -1 (BAC 310O7) 22.9 kb

23.2 kb eBSOlV-2 (BAC 73B22)

ORF1 ORF2

ORF3

Viral genome

1 locus / di allélic

1 locus / mono allélic eBSImV

(BAC 68C24) 15.8 kb

eBSMysV-1

(BAC 29H14) 11.3 kb

eBSMysV-2

(BAC 86I03) 12 kb

Infectious allele Non infectious allele

1 locus / mono allélic

2 loci / mono-allélic

15.8 kb

Gayral P, Noa-Carrazana JC, Lescot M, Lheureux F, Lockhart BE, Matsumoto T, Piffanelli P, Iskra-Caruana M-L. (2008) J Virol. 82: 6697-710.

Iskra-Caruana M-L, Baurens FC, Gayral P, Chabannes M. (2010). Mol. Plant Micr. Interact 23: 1394-402 Gayral P, Blondin L, Guidolin O, Carreel F, Hippolyte I, Perrier X, Iskra-Caruana M-L (2010) J. Virol 84: 7346-59

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PCR Markers

OBINO L’EWAI

eBSOlV-1 eBSOlV-2

GOLDFINGER

eBSGFV-7 eBSGFV-9

eBSImV-1

IMOVE

eBSImV-2

- Structures - Integration

- Allèles

eBSMysV-1

IMOVE

eBSImV-2

eBSMysV-2

MYSORE

eBSV specific signature for each BSV species

Internal structure definition is ongoing

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GF OL Im

PKW BBw GF7/GF9 OL1/OL2 Im

B. Honduras BBw GF7/GF9 OL1/OL2 n

Pisang Batu BBw GF7/GF9 OL1/OL2 Im

B. Cameroun BBw GF? OL? Im

Pisang Klutuk BBw GF7/GF9 OL1/OL2 Im

Porp (Popoulou) AABcv n OL? Im?

Langka AABcv n OL? n

Safet Velchi ABcv GF? OL1 n

Ney Poovan ABcv GF? OL1 n

Figue Pomme (Ekona) ABcv GF? OL1 n

Accessions with M. balbisiana genetic background were screened by PCR, using primer pairs differentiating infectious and non infectious eBSVs

OL1, GF7, Im: infectious OL2, GF9: non infectious n : no eBSV

Figue Pomme (Ekona) ABcv GF? OL1 n

FlhorBan 902 AAAcv n n n

IDN 110T AAAA n n n

Kunnan D ABcv n OL? Im?

Kunnan T AABB n OL? Im?

FlhorBan 914 AABhyb GF9 OL2 Im

FlhorBan 910 AABhyb GF7 OL2 Im

French Clair AABcv GF7 OL1 n

Kelong Mekintu AABcv GF? OL1 n

Burro (CEMSA) ABBcv GF7/GF9 OL2/OL2 Im

Pelipita ABBcv GF7/GF9 OL1/OL2 Im

Bunga Oisan AABcv GF7 OL1 n

Several accessions harbour both infectious and non infectious eBSOLV and eBSGFV alleles

Modified alleles are present in some cultivars (Cameroun, Kunnan, Kelong Mekintu…)

cv Honduras is free of eBSImV

(11)

Breeding X ♀

Seeds No seeds

Embryo rescue Failed

Plantlets

Plants weaning

eBSV signatures

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B. HondurasBBw GF7/GF9 OL1/OL2 n

X

B. HondurasBBw GF7/GF9 OL1/OL2 n

Progeny of 70 screened by PCR

OL1/OL2 OL1/OL1 OL2/OL2

GF7/GF9 30 13 7

Allelic signatures (%)

GF7/GF7 7 6 3

GF9/GF9 10 3 4

eBSV signature results fit expected segregation ratios

4 % of plants are devoid of all infectious alleles

(13)

B. Cameroun BBw GF ? OL? Im B. HondurasBBw GF7/GF9 OL1/OL2 n

X

Progeny of 153 screened by PCR

OL1/OL2 OL1 OL2 ND

Allelic signatures (%)

GF7/GF9 7 13 7 2

GF7 3 14 4 2

GF9 1 14 14 4

ND 0 3 2 11

24 % harbour modified eBSOLV and eBSGFV alleles

(14)

B. Cameroun BBw GF ? OL? Im B. HondurasBBw GF7/GF9 OL1/OL2 n

X

Progeny of 153 screened by PCR

OL1/OL2 OL1 OL2 ND

GF7/GF9 - - - -

Allelic signatures (%) Imové -

GF7 - - - -

GF9 - - 1.3 1.3

ND - - - 7.2

1.3 % are devoid of all infectious alleles

(15)

Molecular screening tools allow:

the study of eBSV alleles segregation

the search for individuals devoid of infectious eBSV alleles

Molecular screening tools allow:

the study of eBSV alleles segregation

the search for individuals devoid of infectious eBSV alleles

M .balbisiana genitors devoid of infectious eBSV alleles

were created and are being used for breeding improved

banana interspecific hybrids

(16)

Unravel the structure of modified eBSV alleles

Southern-blot

Sequencing

Unravel the structure of modified eBSV alleles

Southern-blot

Sequencing

Study the infectious status of modified alleles

Study the infectious status of modified alleles

Optimize molecular screening tools specific of modified eBSV alleles

Optimize molecular screening tools specific of modified eBSV alleles

Study the infectious status of modified alleles

CMR X IDN110 (AAB) progeny is being assessed for the expression of infectious eBSVs

Study the infectious status of modified alleles

CMR X IDN110 (AAB) progeny is being assessed

for the expression of infectious eBSVs

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Lydiane Bonheur Isabelle Acina

Mambole Marie Umber

Jean-Philippe Pichaut

Pierre-Yves Teycheney

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