Factors influencing transmission of alfalfa mosaic virus through seed of annual medics (Medicago spp.) and the genetic control of seed transmission rate

1997 ◽  
Vol 48 (7) ◽  
pp. 989 ◽  
Author(s):  
W. Pathipanawat ◽  
R. A. C. Jones ◽  
K. Sivasithamparam
Keyword(s):  
Mosaic Virus ◽  
Genetic Control ◽  
Transmission Rate ◽  
Alfalfa Mosaic Virus ◽  
Seed Transmission ◽  
Virus Concentration ◽  
Rate Condition ◽  
Reciprocal Crosses ◽  
Transmission Rates ◽  
Annual Medics

Factors likely to influence rates of transmission of alfalfa mosaic virus (AMV) through seed to seedlings of annual medics (Medicago spp.) and genetic control of the magnitude of its seed transmission rate were investigated in plants from 17 early-flowering accessions of M. polymorpha and in progenies of crosses involving M. murex cv. Zodiac × accession 5320 as parents. Plants were graft-inoculated when 6 weeks old to ensure successful and uniform infection. To exclude variation in seed transmission rates due to virus isolate or temperature, only 1 AMV isolate was used and the plants were kept under uniform temperature conditions. In M. polymorpha, significant differences were found between accessions in the levels of AMV transmitted through seed to progeny seedlings, SA 8250 giving the highest mean level of seed transmission (52%) and SA 4188 the lowest (3%). Neither virus concentration nor symptom severity influenced the rates of seed transmission obtained. However, part of the variation in seed transmission rates found in these accessions was related to their flowering times, seed transmission rates increasing as the interval between inoculation and owering increased. In seed samples collected from individual graft-inoculated plants of M. murex from (i) the F2 generation from crosses and reciprocal crosses, and (ii) the backcross progenies, the rates of transmission of AMV through seed to seedlings ranged from 0 to 77% and showed a continuous pattern of variation. Also, there was evidence of transgressive segregation for the low seed transmission rate condition. This indicates that the low seed transmission rate condition for AMV in medics is quantitatively inherited and under polygenic control. In contrast, when the pods from F2 progeny plants from the crosses and reciprocal crosses were examined, the segregation ratios obtained revealed that the smooth pod character from parent accession 5320 was controlled by a single recessive gene, for which the name sp is proposed. The presence in a plant of gene sp, or of its spiny pod-determining allele from the other parent cv. Zodiac, was not correlated with low seed transmission rates of AMV. It is concluded that selection for low rates of seed transmission and a population breeding approach can be used to produce improved M. polymorpha and M. murex cultivars with good resistance to seed-borne AMV

Infection of alternative hosts associated with annual medics (Medicago spp.) by alfalfa mosaic virus and its persistence between growing seasons

1994 ◽  
Vol 45 (7) ◽  
pp. 1413 ◽  
Author(s):  
SJ McKirdy ◽  
RAC Jones
Keyword(s):  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Trifolium Subterraneum ◽  
Seed Transmission ◽  
Herbaceous Plant ◽  
Alternative Hosts ◽  
Growing Seasons ◽  
Alternative Means ◽  
Annual Medics ◽  
Annual Medicago

Under conditions of natural alfalfa mosaic virus (AMV) spread, five plant species found associated with annual Medicago spp. (medics) were infected commonly and another seven sporadically. Ten of these were new records. Because seed of herbaceous plant hosts provides a possible route for virus persistence through dry summer conditions, AMV seed transmission was tested for in alternative hosts. Of ten species systemically infected by sap inoculation with AMV, seed transmission was detected in Melilotus indica (l0%), Ornithopus compressus (0 1%) and Stachys arvensis (2%). Seed of seven naturally infected potential alternative host species was tested, and seed transmission found in Crassula decumbens (0. 1%), M. indica (3%), 0. compressus (0.2%), S. arvensis (0.4%) and Trifolium subterraneum (2%). Carry-over of AMV through seed transmission was detected in seedlings of Hypochaeris glabra (0.2%) and M. indica (0.6-0.8%) that germinated naturally in the field. In grazed, self-regenerated Medicago murex and M. polymorpha swards sown in 1987, the virus persisted for at least seven growing seasons. Levels of infection in M. polymorpha seed produced each year declined, but levels in the general seed bank remained higher due to presence of older seed. It is concluded that under the conditions of broadacre agriculture in the Mediterranean-type climate of Western Australia, seed transmission in C. decumbens, H. glabra and volunteer 0. compressus is an alternative means by which AMV can persist over summer to act as sources of AMV for spread within annual medic pastures. However, persistence through seed of the annual medic cultivars sown and of naturalized annual Medicago species is the principal means of persistence. AMV persists readily from year to year following sowing of infected seed and is likely to cause a recurrent disease problem in annual medic pastures.

Studies on seed and pollen transmission of Alfalfa Mosaic, Cucumber Mosaic and Bean Yellow Mosaic Viruses in cultivars and accesions of annual Medicago species

1995 ◽  
Vol 46 (1) ◽  
pp. 153 ◽  
Author(s):  
W Pathipanowat ◽  
RAC Jones ◽  
K Sivasithamparam
Keyword(s):  
Transmission Rate ◽  
Seed Transmission ◽  
Transmission Rates ◽  
Pollen Transmission ◽  
Immature Seeds ◽  
Annual Medicago ◽  
Carry Over ◽  
Transmission Studies ◽  
Medicago Species ◽  
Seed Coats

Seed and pollen transmission of alfalfa mosaic (AMV), cucumber mosaic (CMV) and bean yellow mosaic (BYMV) viruses was investigated in annual medic species (Medicago spp.). For seed transmission studies with AMV, graft inoculation was used to establish early infection and maximize possible transmission rates to seedlings via seed, but with CMV and BYMV aphid and/or graft inoculation was used. For pollen transmission studies, pollen taken from virus-infected plants was used to pollinate healthy plants, the seed collected and seedlings tested. The rates of AMV isolate OUI-2 transmission to seedlings through seed produced on infected plants ranged from 6 to 53% for commercial cultivars and from 7 to 65% for accessions. Accession DZA 3181.1.1 of M. sphaerocarpos had the highest overall AMV transmission rate. Only two cultivars, cvv. Borung and Hannaford of M. truncatula, and accession SA 4268 of M. orbicularis, had transmission rates of less than 10%. The rates of CMV transmission to seedlings via seed produced on infected plants of the cultivars and accessions tested were 0.3 to 13%, the greatest being found in M. polymorpha cv. Serena, but 6 out of 11 had no detectable transmission. The rates of BYMV transmission to seedlings via seed of the cultivars and accessions tested were 0.3 to 1%, but in 12 out of 15 none was detected. AMV isolate OUI-2 was transmitted to 52% of seedlings via seed produced on healthy M. polymorpha cv. Circle Valley plants pollinated from infected plants. In contrast, no transmission to seedlings by either graft-inoculation or pollination of M. polymorpha plants was detected with a second AMV isolate, OUI-1, which appeared to have lost its ablilty to be seed transmitted. No CMV or BYMV transmission to seedlings via pollination of healthy plants with pollen from infected plants was detected in M. polymorpha cvv. Circle Valley or Santiago. When empty immature pods, and dissected seed coats and embryos from immature seeds produced on AMV-infected plants of M. polymorpha were tested, AMV isolates OUI-I and OUI-2 were detected in all pods and seed coats, but only in 59% of embryos with isolate OUI-2 and in none with isolate OUI-1. CMV was detected in 12% of embryos tested from immature seeds produced on CMV-infected M. polymorpha cv. Serena plants. Transmission of all three viruses through seed, and of AMV through pollen, is cause for concern in annual medic breeding and evaluation programs. Moreover, carry-over outside the growing season in medic pastures is possible through seed with all three viruses.

An epidemic of cucumber mosaic virus in South Australian lupins

1985 ◽  
Vol 36 (2) ◽  
pp. 267 ◽  
Author(s):  
E Alberts ◽  
J Hannay ◽  
JW Randles
Keyword(s):  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Vicia Faba ◽  
Transmission Rate ◽  
South Australia ◽  
Trifolium Subterraneum ◽  
Seed Transmission ◽  
Severe Stunting ◽  
Experimental Host Range

Many Lupinus angustifolius crops in South Australia showed a high incidence of severe stunting and leaf epinasty during 1983. The epidemic was attributed to infection with cucumber mosaic virus. The virus was also recovered from Trifolium subterraneum cv. Geraldton, Medicago polymorpha, Vicia faba, Erodium sp. and Arctotheca calendula growing in or adjacent to lupin crops. The experimental host range of the virus included T. subterraneum cv. Clare, T. repens, Pisurn sativum, Vicia faba and Cicer arietinum. A seed transmission rate of 12-15% was demonstrated in field-infected lupins, and it is concluded that the epidemic probably arose through primary introduction of virus into crops in seed, followed by secondary spread by aphids. The possible role of alternative host species as a reservoir is discussed.

scholarly journals Transgenic Virus Resistance in Crop-Wild Cucurbita pepo Does Not Prevent Vertical Transmission of Zucchini yellow mosaic virus

Plant Disease ◽  
2015 ◽  
Vol 99 (11) ◽  
pp. 1616-1621 ◽  
Author(s):  
H. E. Simmons ◽  
H. R. Prendeville ◽  
J. P. Dunham ◽  
M. J. Ferrari ◽  
J. D. Earnest ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Cucurbita Pepo ◽  
Transmission Rate ◽  
Zucchini Yellow Mosaic Virus ◽  
Seed Transmission ◽  
Yellow Mosaic Virus ◽  
Yield Reduction ◽  
Significant Difference ◽  
Transgenic Squash ◽  
Transgenic Virus Resistance

Zucchini yellow mosaic virus (ZYMV) is an economically important pathogen of cucurbits that is transmitted both horizontally and vertically. Although ZYMV is seed-transmitted in Cucurbita pepo, the potential for seed transmission in virus-resistant transgenic cultivars is not known. We crossed and backcrossed a transgenic squash cultivar with wild C. pepo, and determined whether seed-to-seedling transmission of ZYMV was possible in seeds harvested from transgenic backcrossed C. pepo. We then compared these transmission rates to those of non-transgenic (backcrossed and wild) C. pepo. The overall seed-to-seedling transmission rate in ZYMV was similar to those found in previous studies (1.37%), with no significant difference between transgenic backcrossed (2.48%) and non-transgenic (1.03%) backcrossed and wild squash. Fewer transgenic backcrossed plants had symptom development (7%) in comparison with all non-transgenic plants (26%) and may be instrumental in preventing yield reduction due to ZYMV. Our study shows that ZYMV is seed transmitted in transgenic backcrossed squash, which may affect the spread of ZYMV via the movement of ZYMV-infected seeds. Deep genome sequencing of the seed-transmitted viral populations revealed that 23% of the variants found in this study were present in other vertically transmitted ZYMV populations, suggesting that these variants may be necessary for seed transmission or are distributed geographically via seeds.

scholarly journals Seed Transmissibility of Alfalfa mosaic virus in Soybean

2010 ◽  
Vol 11 (1) ◽  
pp. 41 ◽  
Author(s):  
B. He ◽  
O. L. Fajolu ◽  
R.-H. Wen ◽  
M. R. Hajimorad
Keyword(s):  
Mosaic Virus ◽  
Alfalfa Mosaic Virus ◽  
Seed Transmission ◽  
Infected Seed ◽  
Seed Transmissibility

Collectively, this report provides unequivocal evidence on Alfalfa mosaic virus (AMV) seed transmission in soybean. Infected seed may serve as a reservoir for survival and spread of AMV in soybean. Accepted for publication 18 November 2010. Published 27 December 2010.

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