: . y ; .- . . .' :
. i
[nom] · 3 . ; i'
... . -._ , · 5. Rice stripe necrosis [nom]: a [nom]
h[eribln[t jïìr den · .-
..
rod-shaped [nom]
[nom]
logical Society of By C. FAUQUET, J.-C. THOUVENEL, D. FARGETTE &
ieat in Ontario. · L. D. C. FISHPOOL
al, transmission, · Phytovirologie, ORSTOM, B P V 51 Abidjan, Côte d'Ivoire
k mosaic [nom]
1966). Studies on est for resistance
35-152.
iv mosaic [nom]: · SUMMARY
hyopndrological
A disease of upland rice known locally as 'crinkling rice disease' has been of barley yellow
hy top arh ological · recorded for many years in a number of West African countries. This
disease was previously thought to be either bacterial in origin or a
Iiosaic [nom] and · physiological disorder. Recently in the Ivory Coast, this disease has been
ogicnl Socieiy of · found to be associated with a rod-shaped [nom] called rice stripe necrosis
t mosaic [nom] · [nom] (RSNV). The symptoms of the disease are: bright yellow stripes
along the leaves, necrosis of the leaves or of the whole plant, dwarfing,
ragu ngsmodus · crinkling and reduced tillering. The percentage of infection varies greatly
sichtigung der · according to the year and to the variety. Crop loss was estimated, for
n Forschungs- · different varieties, to vary between 14% and 100%. The agent is [nom]
Pflanzenzüch-
and a [nom] fungus vector of the order Plasmodiophorales, Pofymy.un
gramhis, is always associated with the diseased plants, both in the field and · .
in laboratory transmission. The causal agent of the disease is not mechanically transmissible from rice to rice (Oryza sativa), but only to other local lesion hosts, and back transmission from local lesion hosts to rice has never been obtained. The rod-shaped [nom] is 20 nm in width and we have observed particles of three different lengths: 110-160, 270 and 3SO nm. An antiserum with a titre of 1/250 has been prepared and no serological relationship was obtained with the several rod-shaped [nom]
tested. Infected rice cells show [nom] aggregates and cytoplasmic inclusion bodies, typical of rod-shaped [nom] RSNV has many properties of the proposed [nom] group including hollow rod-shaped particles with several components and transmission by a [nom] fungus. Furthermore, the amino acid composition of the coat protein of RSNV particles is very different from [nom] and may be typical of '[nom]'.
INTRODUCTION
Until 1978, only one [nom] had been isolated from rice in Africa, rice yellow mosaic [nom] (RYMV; Fauquet & Th
1
[nom] WITH FUNGAL VECTORS
[nom] transmitted by chrysomelid beetles. For many years in West
Africa, another disease was known to appear on upland rice (Oryza sativa) cultures. This disease which develops in young seedlings was called, because of its symptonis, 'rice crinkling disease'. This disease was first described from the Ivory Coast by Louvel c!! Bidaux (1977) and several hypotheses as to the nature of the causal agent have been proposed: a physiological disorder, a nematode (Vuong, 196S), or a ,bacterial agent
(Buddenhagen, pers. comm.). However, most of the symptoms in infected rice seedlings resemble those caused by rice stripe [nom], a [nom] isolated in South East Asia (Ling, 1972; Ou, 1972). Indeed, Fauquet eC Thouvenel
(19S3) later demonstrated that this 'rice crinkling disease' was associated with virions that were rod-shaped, and [nom] The results obtained showed that the [nom] had not previously been described from rice or from other graminaceous plants. As a result, because of the typical symptoms induced (Plate 3), we proposed the name: rice stripe necrosis [nom]
(RSNV). The natural vector of the disease is the [nom] fungus, Polyriijwr granihis, which colonizes the roots of rice in the infected areas. The modes of transmission of the agent were identified and a number of biochemical and biological parameters were studied. As far as we can tell, this [nom]
shares most of the properties of the newly proposed [nom] group
(Shirako 22 Brakke, 1953). The objective of the present paper is, with the addition of new information, to summarize the current siate of knowledge of this disease.
THE DISEASE
Symptomatology. Louvel & Bidaux (1977) gave an accurate description of the symptoms of this disease, which we repeat briefly here. In its symptomatology we have to distinguish between three levels of descrip-tion: the precocity of the infection, the different types of symptoms and the intensity of the symptoms. The first characteristic of the disease is its very early infection of the crop, i.e. some three weeks after sowing severe symptoms may be seen on seedlings. This suggests that the vector, whatever it is, is active soon after germination of the rice. The chronological order of appearance of the symptoms is as follows: chlorotic
1 · or yellow stripes on leaves (Fig. 5-1(2)), then a general stunting of the plant
(Fig. 5-l(l)), followed by necrotic stripes along the limb, reduction of tillering (very often one tiller only; Fig. 5-1(3)), and crinkling distortion of
i · young leaves (Fig. 5-l(3)).
The intensity of symptoms varies greatly, depending upon date of infection and variety. Often, there is a necrosis of t h e whole plant about 30 days after infection and when the percentage of infection in the field is high, the infected patch looks like an area of low stunted rice (Fig. 5-l(1)).
72
'
.
'. ..,y · '-.~~~<,,.EX*-v. ...&"L+?
4
>-----.%.y-.
.*-.&,.&:*giL?+?
= - $ $ $ * -
Fig. 5-l(1) Field of I
Fig. 5-1(2) YCIIOW SI rice stripe necrosis vir
Fig. 5-l(3) Rice p1;1 showing I i 1 t I L: t i 1 IC r i II g
Fig. 5-1 (3) Malforiil necrosis [nom]
i:
]y years in West ice ( ~ r y z sativa) n
/
dings was called, is disease was first x (1977) and several ve been proposed: a or a bacterial agent symptoms in infected us, a [nom] isolated in auquet ¿Q Thouvenel sease' was associated
The results obtained
)ed from rice or from he typical symptoms itripe necrosis [nom]
4 fungus, Polynzyxa ed areas. The modes mber of biochemical e can tell, this [nom]
;ed [nom] group nt paper is, with the t state of knowledge
urate description of
riefly here. In its · i
e levels of descrip-if symptoms and the le disease is its very fter sowing severe that the vector, I of the rice. The s follows: chlorotic
+unting of the plant
I
imb, reduction of kling distortion of
I
!ng upon date of ole plant about 30 ion in the field is rice (Fig. 5-l(1)).
Fig. 5-1( 1) Field of upland rice contnminatcd \vit11 rice stripe necrosis [nom]
Fig. 5-1(2) Yellow stripe symptoms on ricc Icavcs of cv. IR.AT IO. infected with rice stripe necrosis [nom] Healthy rice leaf at bottoni.
Fig. 5-1(3) Rice plant, cv. IRAT 10. infected !viti1 rico >trip? necrosis [nom], shotving little tillcring and poor JcvelLqmcnt of the tillers SS Jays after soiviilg.
Fig. 5-1(4) Malformation of R p:inicle of cv. IKAT 10, induced by rice stripe necrosis [nom]
73
[nom] WITH FUNGAL VECTORS
If infection occurs later thc plant does not die, but tillering will be considerably reduced and will most often give only one very distorted and almost sterile panicle (Fig. 5-1(4)). If infection is incomplete, the plant will grow one or niore tillers which compete with the infected tillers and will eventually produce healthy panicles.
Inciderice of the disease. Levels of disease incidence and their effects on growth and yield of infected rice have only been estimated in the Ivory
Coast (Louvel s( Bidaux, 1977; Fauquet, unpubl.). Assessment of disease incidence in a crop must take into account its impact on individual plants and the frequency with which it occurs. The impact of the RSNV is dependent on the age of infection of the plants, the number of infected tillers on each plant, on the intensity of the symptoms on each tiller and on the variety considered. I n a study made with three rice varieties, three different stages i n the development of the disease were distinguished: from 21 days after sowing (DAS) to 39 DAS when the number of diseased plants in the field increases. from 39 DAS to 45 DAS when there is a decrease in the number of infected plants (this stage corresponds to thc end of tillerage of the rice), and finally from 45 DAS to S5 DAS when the number of infected plants remains constant. This apparent reversion of symptoms is a result of competition froni healthy tillers. Within a collection of 30 varieties tested in the Ivory Coast in 1977 and 73 tested in 1981 and 1983, the percentage of infected plants ranged from O to 48% in 1977 (Louvel ¿Q
Bidaus, 1977) and from O to 100% in 1951 and 1983 (Fauquet, unpubl.).
For each set of observations, the niost susceptible varieties were Lung
Sheng 1 and its hybrids, including IR8. Crop losses with the three susceptible varieties, estimated from the number of panicles, varied between 76 and 92% for infected plants, and from 13 to 16% over the whole plot.
Epidemiology of the disease. T h e epidemiology of the disease has not received much attention from research workers, therefore relevant data are almost non-existent. T h e disease is not a severe problem in West
Africa; it recurs erratically over the same areas from season to season.
Nevertheless, field observations indicate that epidemics occur when short periods of rain alternate with long periods of drought, such as often occur at the beginning of the rainy season, which is also the time for planting upland rice. The disease appears in patches of variable size in the fields, but there is no correlation between the low growth areas and the infected areas within the rice fields. It has been noted that the percentage of infection is greater when one rice crop succeeds another. The disease has been observed in inany different parts of Ivory Coast (Fauquet, unpubl.), Nigeria (Rossel, pers. comm.), Liberia and Sierra Leone (Buddenhagen, pers. comm.) with apparently the saine pattern and importance of spread.
74
[nom] transmissior1 of t h discrete, progressively which was tcsted and 1.
was always associated, of a [nom] fungus, P.
t ransni ission cs pe ri niel the field (Fig. 5-2(1)).
45% of rice seedlings v a depth of O to 20 cm f l
Fig. 5-2(1) [nom] transm
IRAT 10. Two diseased plants at the rear.
Fig. 5-2(2) Resting spo
IO, naturally infected wi
Fig. 5-2(3) Cystosori o naturally infected with Fig. 5-2(4) T\VO cystos
IRAT 10, infected dur necrosis [nom]
Ice and their effects on estimated in the Ivory
. Assessment of disease
3ct on individual plants
)act of the RSNV is e number of infected s on each tiller and on : rice varieties, three re distinguished: from ber of diseased plants there is a decrease in to the end of tillerage when the number of sion of symptoms is a lection of 30 varieties
1951 and 1953, the ) in 1977 (Louvel &
(Fauquet, unpubl.).
varieties were Lung s e s with the three of panicles, varied
13 to 16% over the
he disease has not
,efore relevant data
2 problem in West
I Season to season.
:s occur when short such as often occur e time for planting e size in the fields, as and the infected the percentage of :r. The disease has
'auquet, unpubl.), ne (Buddenhagen, ortance of spread.
IUCE smim NECROSIS [nom]
[nom] transniission of the tliscasc agent. The ficlcl spread of the disease in cliscrctc, progrcssively cxpnncling patches, indicateci [nom] transmission, w h i ch ivns t c s t e cl a II d co n f i r ni e d by 1 a bora tory ex pe ri ni e n t s. The disease was always xisociiited, i n the root cells of infected plants, with the presence of a [nom] fungus, P. gmmirzis. All infected plants obtained by [nom]
transmission cxperinicnts developed the symptoms typical of the disease in the ficld (Fig. 5-2( 1)). In laboratory [nom] transmission experiments, up to 45% of rice secdlings \vere infected when the [nom] used was extracted from a depth o f O to 20 cm from around infected plants in the field, as compared
Fig. 5-2(1) [nom] transmission experiment with rice stripe necrosis [nom] and cv.
IRAT 10. T\vo diseased plants are shown in the foreground with three healthy plants at the rear.
Fig. 5-7_(2) Resting spores of Po1yniy.m grottiinis in the rootlets of rice cv. IRAT
10, naturally infected with rice stripe necrosis [nom]
Fig. 5-2(3) Cystosori of Polymyxn graniitzis in the rootlets of rice CV. IRAT 10, naturally infected with rice stripe necrosis [nom]
Fig. 5-2(3) Two cystosori of Polyniyra graminis in a cell of a rootlet of rice, cv.
IRAT IO, infected during a [nom] transmission experiment with the rice stripe necrosis [nom]
75
[nom] WITH FUNGAL VECTORS
with 9% levels of infection in the [nom] extracted from the same depth around healthy plants. Contaminated [nom], dried for 60 days, transmitted the disease to 31% of seedlings tested. Using [nom] from pots containing plants which showed positive transiiJission, it was possible to obtain further positive transmissions, sometimes up to 100%. [nom] transmission esperi-meiits \vere also positive when sterilized [nom] w s inoculated with the washed roots of infected plants or with fungal zoospores released from infected roots into water arid concentrated by low-speed centrifugation.
THE VECTOR
The presence of n [nom] fungus infecting rice roots was demonstrated.
using n lactophenol staining method (Britton & Rogers, 1963) (Fig.
5-2(2)). The size and shape of the cystosori (Fig. 5-2(3)) and plasmodia observed in the root cells of infected rice suggested that the fungus involved might be P. gratnirlis (Karling, 1968; Ledingham, 1939; Rao.
1965). This hypothesis was reinforced by the fact that the fungi of this group have specific plant hosts and P. grmtitiis invades only graminaceous plants (Karling, 196s; Teakle, 19SO). Plants infected by [nom] from [nom].
either in natural or artificial conditions, always contained P. grcir?zitiis in the cells of their rootlets.
Transmission esperiments were performed with nematode vectors
(Fauquet, unpubl.). Xiphitietm spp. were found in very small quantities in
[nom] samples from contaminated fields but we were unable to correlate the disease transmission with them.
Rice mealybug, Ripersiu o r y t ~ which , · is known to induce crinkling and
malformations of the affected plants, were also tested as a vector of RSNV.
Rice mealybugs, bred on rice seedlings infected by RSNV, were transferred to healthy rice seedlings. The symptoms that developed were
,; not those of RSNV (Fauquet & Thouvenel, 1953).
THE [nom]
Mechanical inoculation. The [nom] is not mechanically transmissible from rice to rice or perhaps only with an extremely low rate of transmission. One positive plant was obtained from more than ten thousand plants tested
(Fauquet & Thouvenel, 1953). Many different inoculation buffers, conditions, techniques and inoculum sources (young leaves and rootlets from field and laboratory infected plants) were tried without success.
Nevertheless, it is possible to obtain local lesions in leaves of Clietiopodizct?t uritaratiticolor or Nicotiana bett/ltatniann inoculated with infected crude rice sap. The local lesions produced on C. aniarotificolor are very similar to those induced by peanut clump [nom] (Tliouvenel 22 Fauquet, 1981).
76
Infection is limited to which enlarge and ¡i symptoms. Symptom appeared also to be r to achieve back tran possible to obtain loc
N . beiirhariiiattu wht inoculum.
Seed transmission. Ti using several thousa field. They were fror.
IRAT 10, IRAT 1 percentage of gerniir occurred (Fsuquet 6
The causal agent. R roots of infected ric
[nom] purification t alternate low and butanol clarificatior purification was pe opalescent bands we isolated bands disp
[nom] with 5% of yield of purified viri infectious on the lo bands observed in s:
lengths: 110-160, 2 rod-shaped, with a width of about 20 n
Electron microscopy
[nom] induces cytopl rod-shaped [nom]
Thouvenel & Fauq number of cells CO paracrystalline cytc inclusions were pre experimentally infe
Serology. The viri prepared with the <.’
. - . . · observed when t h c
g. .... . ’ · toinato niosi1ic tob
’.”. . . . - i. , .P.’
...
nys, transmitted
irmulated with the pores released from :ed centrifugation.
was demonstrated, .Ogers, 1963) (Fig.
(3)) and plasmodia d that the fungus tgham, 1939; Rao, It the fungi of this only graminaceous by [nom] from [nom], ?ed I-'. grntnitlìs in nema t ode vectors small quantities in de to correlate the
h c e crinkling and i vector of RSNV.
>y RSNV, were t developed kvere
ansniissible fro111
.ansmission. One
nd plants tested dation buffers, ves and rootlets
,vi thou t success.
If CI1 etiopodìunr infected crude e very similar to h q u e t , 19Si).
RICE STRIPE NECROSIS [nom]
Infection is limited to the inoculated leaf. Symptoms appear as yellow spots which enlarge and invade the whole leaf, which shows typical oak-leaf symptoms. Syniptoms i n N. benrhnrniana took the form of yellow spots and appeared also to be restricted to the inoculated leaves. It was not possible to achieve back transmission to rice from local lesion hosts, but it was possible to obtain local lesions in inoculated leaves of C. amnrantico[or or N . benthanliana when the same plant species was used as a source of inoculum.
Seed transmission. T h e possibility of seed transmission has been examined using severa1 thousand rice seeds, collected from infected plants in the field. They were from the most susceptible varieties of rice, Lung Sheng 1, IRAT 10, IRAT 13, 63 X S3, LS 103 and Dourado précoce. The percentage of germination was very low, but no transmission of the disease occurred (Fauquet & Thouvenel, 1983).
The causal agent. RSNV could be purified both from the leaves and the roots of infected rice seedlings. The purificatioz method was a classical
[nom] purification technique using potassium phosphate buffer with alternate low and high speed centrifugations, following chloroform-butanol clarification (Fauquet & Thouvenel, 1953). The final step of purification was performed in a sucrose density gradient where three opalescent bands were differentiated (Rf = 0.40,0.51 and 0.56). The three isolated bands displayed biophysical properties typical of rod-shaped
[nom] with 5% of nucleic acid (Fauquet & Thouvenel, 1953). The total yield of purified [nom] was on average 10-15 mg/kg. The purified [nom] is infectious on the local lesion hosts cited above, but not rice. The three bands observed in sucrose gradients correspond to three different particle lengths: 110-160, 270 and 380 nm (Fig. 5-3). The [nom] particles are rod-shaped, with a hollow centre of different lengths but with the same width of about 20 nni (Fig. 5-4).
Electron microscopy. In the parenchyma cells of infected rice seedlings, the
[nom] induces cytoplasmic inclusions that resemble the inclusions of other rod-shaped [nom] (Christie & Edwardson, 1977; Jackson & Lane, 1981;
Thouvenel & Fauquet, 1981; Francki, Milne & Hatta, 19S5). A large number of cells contains [nom] particles (Fig. 5-4(1), (2), (3)) and paracrystalline cytoplasmic inclusions (Fig. 5-4(4)). These cytoplasmic inclusions were present both in the infected plants from the field and in experimentally infected seedlings.
Serology. The [nom] is poorly immunogenic but using the antiserum prepared with the purified [nom] having a titre of 1/250 no reaction was observed when the following [nom] were tested: tobacco mosaic and tomato mosaic [nom]; the [nom] tobacco rattle and pea
77
I · .
'.... ..-.__.._ ....' c
...
~
[nom] \\'17'H FUNGAL VECTORS
I
n · n
7 I I 71 n l
HISTOGRAM OF · P A R T I C L E L E N G T H OF R S N V
1
Fig. 5-3(1) Histogram of purified particle lengths of the stripe necrosis [nom] from a mixture of the three bands obtained from a sucrose density gradient.
Fig. 5-3(2) Electron micrograph of rice stripe necrosis [nom] particles purified on a sucrose density gradient and stained with uranyl acetate. Bar represents 100 nm.
early browning; barley stripe mosaic [nom]; [nom] wheat mosaic
[nom] (SBWMV), Nicotimza vefufitza mosaic [nom], beet necrotic yellow vein
[nom] (BNYVV) and peanut clump [nom] (Fauquet & Thouvenel, 1953).
Properties of the coat protein. The molecular weight of the coat protein of RSNV, determined by polyacrylamide gel electrophoresis, is 24 O00 d (Fauquet, 1955). The number of amino acids per molecule is as follows:
ASP (29), THR (14), SER (E), GLU (20, PRO ( 9 ) , GLY (20), ALA
78
Fig. 5-4(1) Electron niicr cytoplasm of a rice cell inf
Fig. 5-4(2) Electron micr cytoplasm of a rice cell inf
Fig. 5 4 3 ) Electron niicr cytoplasm of a rice cell in!
Fig. 5-4(4) Electron mi cytoplasm of a rice cell in
@O), C Y S (2), VAL (1
(61, HIS (6), LYS (IO), This amino acid compc typical of [nom] trar
Dejardin Csr Thouvcnel 1
.. , . .. . ,>.
RSNV
1
ecrosis [nom] from adient.
'cles purified on a )resents 100 nm.
le wheat mosaic
.otic yellow vein wenel, 19S3).
coat protein of :is, is 24000 d e is as follows:
Ly @O), ALA
Fig. 5-4(2) Electron niicrograph shotving [nom] particles (V) aceregated in the -- cytoplasm of a rice cell infected with rice stripe necrosis [nom]
Fig. 5-4(3) Elt'ctron micrograph shotving [nom] particles (i7) aggregated i n the cytoplasm of a rice cell infectecl with rice stripe necrosis [nom]
c-
Fig. 5-4(4) Electron micrograph showing paracrystal ir~clusion (PI) in the cytoplasm of a rice cell infected Ivith rice stripe necrosis [nom]
cys (31, VAL (1.51, MET (2), ILE (9), LEU (16), TYR (7), PHE
( 6 ) , HIS (61, LYS (IO), ARG (13), T R P (3) (Faucjuet 6r Thouvenel, 1987).
This amino acid composition is characteristic of rod-shaped particles and typical of [nom] transmitted by [nom]-fungi (Fauquet, 19S5; Fauquet, Dejardin & Thouvenel, 19S6a; 19SGb).
79
[nom] WITH FUNGAL VECTORS
DISCUSSION
A rod-shaped [nom] (RSNV) is always associated with rice crinkling disease which occurs occasionally in West Africa (Louvel Pr Bidaux, 1977; Fauquet
Pr Thouvenel, 19S3). This [nom], although it could not be artificially transmitted to healthy rice, is nonetheless the most probable causal agent of the disease. All the results obtained point to it being transmitted by a
[nom] fungus; no other likely agent could be identified. The symptoms of RSNV are typical of those caused by other rod-shaped [nom] in cereals
(Atabekov Rr Novikov, 1971; Brakke, 1971; Inouye Sr Fujii, 1977; Ling, 1972) and the results of [nom] transniission experiments with the disease agent are indicative of fungus transmission: P. grmiuis is the fungus probably involved.
There are at least two [nom] that infect rice and are transmitted by P.
g r a n h i s (Ling, 1972). Furthermore, rice necrosis mosaic [nom] ( R I W V ) induces symptoms in rice leaves sirnilar to those associated with RSNV.
However, RNMV has rigid filamentous particles with predominant lengths of 275 and 550 nm and induces pinwheels in the infected cells (Inouye Rr
Fujii, 1977) thereby differing from RSNV.
Among other [nom] infecting graminaceous plants, only [nom]
wheat mosaic (SBWIvlV) (Brakke, 1971) and oat golden stripe [nom]
(Plumb, Catherall, Chamberlain eC Macfarlane, 1977) are fungus-transmitted and have similar rod-shaped particles. SBWMV and OGSV are easily mechanically transmitted to different hosts and SBWMV does not infect rice. By contrast RSNV naturally infects rice but cannot be transmitted mechanically. Furthermore, SBWMV is not serologically related to RSNV.
Amongst [nom]-transmitted rod-shaped [nom], beet necrotic yellow vein
[nom] (BNYVV) resembles RSNV in appearance and modal length, but
BNYVV does not infect graminaceous plants and the two are not serologically related.
The rod-shaped [nom] isolated from infected rice plants is composed of particles of at least three different lengths: 110-160, 270 and 380 nm.
However, it is not known whether all particles are essential for infection.
Although neither the type of nucleic acid nor the number of genomic components are known, RSNV has affinities with the [nom] as judged by amino acid composition of coat proteins (Fauquet, Desboise, Fargette
8r Vidal, p. 19, this volume).
At present, the disease does not seem to be economically important for upland rice culture in Africa, although the impact of the disease on individual infected plants can be very severe or even lethal. Conditions necessary for the development of the disease are imperfectly known but seem to reflect the epidemiology of the fungal vector. Apparently, this disease is present over wide areas of West Africa but it does not appear to be spreading and occurs a t a relatively low frequency. Thc range of varietal so
I
i
'I
l
i
i
f
susceptibility is .
1
varieties. Conseq
offer an appropri'
ATAUEKOV, J. G . & P
Descriptions of DRAKKE, hf. K. (197.
Plaiit VirimJ, DRlTTON, 51. P. & ROI i n roots of cree
i · CHRISTIE, R. G. Sr ED'
Virils Incliisiot
Series, No. 9, 1
F..\UQUET, C. (1985 cqmidaire. Thè
!
FAUQUET, C. & THOU'
Disease Report<
FAUQUET, C. &THOU\
avec la maladie de l'Acndét?iie 1
FAGQUET, C., DEJARL
composition of
[nom] group. 1.
25, 1-13.
FAL'QUET, C.. DEJARD
composition of
[nom] group. II.
classification pr
FRANCKI, R. I. B . , M I
CRC Press, Bo
INOUYE, T. & FUJII, S.
plant virues Nc
JACKSON, A. O. & L A bifcctiotis and North-Holland
KARLING, J. s. (1965
New York, 256
LEDINGHAM, G . A .
plasmodiophor;
17, 38-51.
LING, K. c. (1972). F
Los Banos, Phi
LOUVEL, D. · & · BID
pathologiques s
Tropicale, XX>-
Ou, s. II. (1972).
I
Surrey, Englan,
PLUMB, R. T., CATHER
[nom] of oats i n
I [nom] in cereals
Fujií, 1977; Ling, j with the disease irlis is the fungus
transmitted by P, \ic [nom] (RNMV) ated with RSNV.
?dominant lengths
id cells (Inouye Rr
1
17)
., only [nom]
lden stripe [nom]
are fungus-hlV and OGSV
CI SBWMV does ce but cannot be not serologically
crotic yellow vein nodal length, but
:he two are not
ts is composed of 270 and 380 nm.
,tial for infection.
nber of genomic
)[nom] as judged esboise, Fargette
Ily important for ' the disease on thal. Conditions
'ectly known but
Apparently, this
les not appear to range of varietal
RICE STRIPE NECROSIS [nom]
susceptibility is very wide and there are resistance genes in certain varieties. Consequently, selection/breeding programmes would seem to offer an appropriate strategy for controlling RSNV.
REFERENCES
ATABEKOV, I . G . ti NOVIKOV, v. K. (1971). Barley stripe mosaic [nom] CMIIAAB, Descriptions of Plant Virilses, No. 65, 4pp.
BRAKKE, M. K. (1971). [nom] wheat mosaic [nom] CMIIAAB, Descriptiotis of Plant Virirses, No. 77, 4pp.
BRITTOS, ar. P. & ROGERS, D . P. (1963). Olpidiiim brassiclie and Polytnyra grartfinis in roots of creeping bent in golf putting greens. Mycologia 55, 755-763.
CHRISTIE, R. G . · EDWARDSON, J. R. (1977). Light and Electron Microscopy of Plant
Virils Zncliuions. Florida Agricultural Experimental Station Monograph
Series, No. 9, 155pp.
FAUQUET, C. (1955). Essai db clmsificariotl des phytovirics par leur protéine capsidaire. Thèse d'Etat, Volume II, 19/12/55, ULP Strasbourg, 387pp.
FXUQUET, c. & THOUVENEL, J.-c. (1977) Rice yellow mottle i n the Ivory Coast. Plant
Disease Reporter 61, 443336.
FAUQUET, c. R: THOUvENEL, J.-C. (1953). Association d'un nouveau [nom] en bâtonnet avec la maladie nécrotique à rayure du riz en Côte d'Ivoire. Conpm Rendiis de I'AcadPtnie des Scietices, Série 0, 296, 575575.
FAUQUET, C., DEJAKDIK, J. T I f O W E N E L , J.-C. (1986a) Evidence that the amino acid composition of the particle proteins of p h n t [nom] is characteristic of the
[nom] group. I. Multidimensional classification of plant [nom] Itifervirology
25, 1-13.
FAUQL'ET, C.. DEJARDIN, J. R: THOUVESEL, J.-C. (1986b). Evidence that the amino acid composition of the particle proteins of plant [nom] is characteristic of the
[nom] group. II. Discriminant analysis according to structural, biological and classification properties of plant [nom] Intervirology 25, 190-200.
FRABCII, R. I . B., ~ ~ I L F E R. , G . 9: HATTA, T. (19S.5). A t h of Plnnt Viricscs, Vol. II.
CRC Press, Boca Raton, Florida, USA, 254pp.
ISOUYE, T. B FUJII, s. (1977) Rice necrosis mosaic [nom] CMZIAAB, Descriptions of plant r~iricses No. 172, 4pp.
JACISOS. A . o. s: LANE, I.. c. (1951). [nom] In Nandbook of Plant Virils
[ttfectiotrs and Compnrative Diagnosis, 565-626. Ed. E. Kurstak, Elsevier, North-Holland Biomedical Press, Amsterdam, Holland.
K A R L I F G , J. s. (1965). The Plnsnzodiopiiorules. Ed. Hofner Publishing Company, New York, 256pp.
LEDINGHAM, G . A . (1939). Studies on Polyttiysn graminis, n. gen. n. sp., a plasmodiophoraceous root parasite of wheat. Canadian Joiirtial of Research
17, 3s-51.
L I N G , K. c. (1972). Rice stripe [nom] In Rice Virils Dbeuses, pp. 52-85. Ed. IRRI, Los Banos, Philippines.
LOUVEL, D. 9: BIDAUX, J.-M. · (1977). Observation d e nouveaux symptômes
pathologiques sur des varietés precoces de riz en Côte d'Ivoire. Agronomie
Tropicale, XXXII 3, 257-261.
o u , s. H. (1972). Rice Diseases. Commonwealth Mycological Institute, Kew, Surrey, England, 14-22.
PLUMB, R. T., CATHERALL, P. L., CHAMBERLAIN, J. A. & MACFARLANE, I . (1977). A new
[nom] of oats in England and Wales. Annales Re Phytopathologie 9, 365-370.
81
[nom] WITH FUNGAL VECTORS
RAO, A. S. (196s). Biology of Po/yt~iyxu grurtiinis in relation to [nom] wheat mosaic [nom] Pkytopatlrology 58, 151G-1521.
SHIRAKO, Y. & BRAKKE, M. K, (1954). Two purified RNAs of [nom] wheat mosaic
[nom] are needed for infection. .lorinial of Cetteral Virology 65, 119-127.
TEAKLE, D. s. (19SO). Fungi. In Vectors ofP/atrt Pathogetis, pp. 417435. Eds. K. F.
Harris & K. Maramorosch, Academic Press, London and New York.
THOWENEL, J.-C. & FAL'QUET, c. (1980). Polyniyxa gratnitiis, on new sorghum species in Africa. Plniil Diseuse 64, 957-958.
THOUVEXEL, J.-c. & FAUQUET, c. (1951). Further properties of peanut clump [nom]
and studies on its natural transnrission. Atznals of Applied Biology 97,99-107. . · .
VUONG. H. H. (1965). Note préliminaire sur la présence des nématodes parasites du riz fi Madagascar. A g r o m m k Tropicnk 10, 1025-1045.
82
Ye
By C. PUTZ, M. W1
Itistitilt Natiotia1 de i
B.P. :
B e et necrotic ye I Io w sugar-beet rhizomani
Po1ymy.w betue, has decade. BNYVV has four different lengths by nieans of electror processing methods. i
[information personnelle]-stranded right-]
of 4 turns, involving possesses a segmente ately. The four R N A been cloned and sequ, determined; RNA-3 L play an important rol
BNYVV isolates f have closely similar a the method of choice are not unambiguou:
means of diagnosis ir
Rhizomania (or roc saccharifera), which rootlets, was observc author was also the fi
[nom] and a fungus (I this fungus were alv plants and Canova i designated as [nom] i
*Abteilung Mikrobit
