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Role of AC3 on Geminiviral Replication

-A journey through past.

Kalyan Kumar Pasumarthy

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WT TGMV-M_AC3-1 Normal Elmer et al., NAR (1988), 16: 7043-60

AC3 Mutation in TGMV

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TGMV-AC3 has role in infectivity and symptom

formationElmer et al., NAR (1988), 16: 7043-60

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1. 2AX2B plant

2. AL1AL2AL3X 2B plant

3. 2A plant

4. 2B plant

5. AL1 plant6. AL2 plant

7. AL1 X2B plant

8. AL2 X2B plant

9. AL3 X2B plant

10. AL1AL2 X2B plant

11. AL1AL3 X2B plant

12. ds supercoiled DNAB

Nicotiana tabacum cv. Samsun

AC3 does not have significant effect on replication of DNA B

Southern blot of transgenic plants with TGMV DNAB as probe

Hayes, RJ., et al., (1989), NAR 17:10213-22

Transgenic studies in TGMV

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AC3 C( AC3

Sunter et al: Virology(1990), 179: 69

TGMV-AC3 Mutation study in protoplasts

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Sunter et al: Virology(1990), 179: 69

Replication of DNA-A Replication of DNA-B

AC3 mutation reduces replication of DNA A & B by 50 fold in

N.tabacum protoplasts

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TGMV

AC3

Transgenics Protoplasts

No significant change

in replication

Drastic reduction in

replication (~ 50 fold)

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Etessami et al., JGV (1991), 72:1005-12

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The progeny of mutant pCLVAC 3-2 were investigated by Southern blot analysis (Fig. 5). For the

purpose of this particular experiment, leaf material was selected that showed similar (mild)

symptoms. For this reason the wild-type and mutant samples contained comparableamounts of viral DN A. The ssDNA and scDNA forms of both genomic components were

produced in the same relative abundance in plants infected with the AC3 mutant and

wild-type virus (compare lanes 3 and 4).

W W W W

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AC3 : 134 Aa M t_AC3 : 122Aa

Morris et al: JGV (1991), 72: 1205

ACMV m

t_AC3

ACMV AC3

ACMV m

t_AC3

ACMV

AC3 Mutation in ACMV

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Morris et al: JGV (1991) 72: 1205

DNA-B transgenic plants agro-infiltrated with AC3 mutant DNA-A

ACMV-AC3 mutation lead to delay and amelioration of disease

symptoms and correleated with significant reduction in DNA-B

replication

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AC3 Mutation in BCTV (california strain)

Stanley et al.,. Virology(1992) 191:396-405

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Plants were observed for symptoms after1 week in Beta vulgaris and3days later in Nicotiana benthamiana

Stanley et al.,. Virology(1992), 191:396-405

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Stanley et al.,. Virology(1992), 191:396-405

The data suggests the type of plant system (natural host/

permissive host) governs the role of AC3 on viral genome

replication

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ACMV AC3

ACMV m t_AC3

ACMV AC3

ACMV m t_AC3

Hormuzdi et al, Virology (1995) 206:1044

AC3 : 136 Aa M t_AC3 : 127Aa

AC3 Mutation in BCTV (logan strain)

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Hormuzdi et al, Virology (1995) 206: 1044

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Hormuzdi et al, Virology (1995) 206: 1044

AC3 of BCTV (Logan strain) has no significant effect on

the viral replication even in host plant

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Hormuzdi et al, Virology (1995) 206: 1044

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Hormuzdi et al, Virology (1995) 206: 1044

However, when the similar experiment was performed in

tobacco protoplasts, replication was reduced

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Hormuzdi et al, Virology (1995) 206: 1044

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Role of AC3 in PYMV Replication Leaf Disc Assay

In leaf discs, AC3 mutation reduces the viral DNA

replication

Sung et al., JGV (1995)76:1773

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AC3Heterogeno s

Activity

Vir s to vir sTGMV and PYMV AC3 enhances DNAA

ACMV AC3 has no effect on DNAA

Strain to strainBCTVAC3(california) enhances replication

BCTVAC3(logan) does not effect replication

Host to ostBCTVAC3 (california) enhances viral replicationin S garbeet and has no effect in Tobacco

System to systemAC3 enhances replication in Protoplast

No effect on replication in Transgenic/Agroinfiltration

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