The role of allelopathy in host-virus relations

G.Kazinczi1, J.Horvath2, A.Takacs1, I.Béres2, R.Gáborjányi2, M.Nádasy2

1Office for Academy Research Groups Attached to Universities and Other

Institutions, University of Veszprém, Georgikon Faculty of Agricultural Sciences

2University of Veszprém, Georgikon Faculty of Agricultural Sciences

Allelopathy (Molish 1937)

• A type of interference among higher plants, where products of secondary metabolism inhibit (less promote) the development of neighbourhood plant

• Earlier only plant-plant, today plant-microorganism interactions

• It is considered as a new alternative way for biological control

Plant viruses make up about 15-30% out of the whole plant diseasesVirus particles create close biologial unit with the plant cellChemical plant protection against viruses is unsuccesfull in vivoSome natural substances are known to inhibit replication and cell- to cell movement of viruses and reduce virus concentration

Mode of action

• It is not yet known exactly, but it can be presumed that natural inhibitors may modify special receptor places on the plant cell surface, therefore adhesion of virus particles can not be happened

The aim of the study

• To examine the effect of allelopathic weed extracts on some host-virus relations

MATERIALS AND METHODS

Fresh plant parts were collected and grinding

Asclepias syriaca

Abutilon theophrasti

Cirsium arvense

DONOR SPECIES

Convolvulus arvensisChelidonium majus

• Plant water extracts were made using 25 g fress biomass/100 ml distilled water

• Extracts were used to spray daily test plants from their 2-4 leaf stages until the end of experiments

Host-virus relations (recipient species)

Chenopodium amaranticolor-Alfalfa mosaic virus

Chenopodium quinoa-Sowbane mosaic virus

Cucumis sativus’Delicatesse’-Zucchini yellow mosaic virus

Solanum nigrum- Obuda pepper virus

• Virus infection (DAS ELISA) From the extinction values we can conclude

from the virus concentration; samples are considered resistant to virus infection: if extinction values do not exceed two times those of the negative control

• Fresh weight(five weeks after inoculations)

RESULTS

0

0,5

1

1,5

2

2,5

C.amaranticolor-AMV

C.quinoa-SoMV C.sativus-ZYMV S.nigrum-ObPV

AE

xtin

ctio

n v

alu

es

a

b

c

d

LSD5%

The effect of C. majus extracts on the virus concentration in test plants (a, C. majus root extract; b, C. majus shoot extract; c, positive control; d,

negative control)Slight, significant reduction in AMV concentration due to C. majus root extractEnhanced virus concentration in S. nigrumNo difference in virus concentration in C. quinoa and C. sativus

0

5

10

15

20

25

30

35

40

C.amaranticolor-AMV C.quinoa-SoMV C.sativus-ZYMV S.nigrum-ObPV

g/pl

ant

The effect of C. majus extracts on the fresh weight of test plants (a, C. majus root extract; b, C. majus shoot extract; c,

positive control; d, negative control)1st column, C. majus root extract; 2nd, C. majus shoot extract; 3rd,

positive control; 4th, LSD5%)

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

1 2 3 4 5 6 7 LSD5%

Ext

inct

ion

val

ues

The effect of water extract on the ObPV concentration in S. nigrum

(1, A. syriaca root; 2, A. syriaca shoot; 3, C. arvense shoot; 4, C. arvensis shoot; 5, A. theophrasti shoot; 6, positive control; 7, negative control)

0

2

4

6

8

10

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14

16

18

1 2 3 4 5 6 LSD5%

g/p

lan

t

The effect of water extracts on the fresh weight of S. nigrum

1, A. syriaca root; 2, A. syriaca shoot; 3, C. arvense shoot; 4, C. arvensis shoot; 5, A. theophrasti shoot; 6, positive control

Conclusions

• Sprayed plant extracts did not inhibit virus infection • Allelopathic plant extracts have different effect on

the development and virus concentration in hosts• One exception was in case of C. majus root extracts,

which reduced significantly not only AMV concentration but also fresh weight of C. amaranticolor

• It seems that there is no relation between allelopathic inhibitory effect of weeds on the development of test plants and virus inhibitory effect in the hosts

Thank you for the attention!Thank you for the attention!