Investigation on seed transmission of cucumber mosaic virus in cowpea

Abstract

Cowpea breeding lines were infected with cucumber mosaic virus (CMV) by mechanical inoculation to investigate seed transmission rates for this virus. Transmission rates ranging from 0% to 6% were scored by symptom assessment. However, when cowpeas grown from seeds of infected mother plants were tested by ELISA, up to 30% of the plants were infected with CMV. Evaluating ELISA for CMV detection in cowpea revealed that virus concentration was highest in flowers and lowest in primary leaves. To compare the capacity of ELISA for CMV detection, the serological test was compared with RT-PCR; ELISA proved sensitive and reliable for detection of CMV in infected tissue. For seed analysis, a non-destructive assay for CMV detection based on tissue blotting of hypocotyls tissue was developed. RESUME Des varietes selectionnees du niebe etaient infectees par inoculation mecanique avec le virus de la mosaique de concombre (CMV) afin d'etudier la transmission par semence de ce virus. Les taux de transmission de l'ordre de 0 % a 6 % etaient enregistres apres l'evaluation des symptomes. Cependant, lorsque les plantes de niebe issues de semences provenant des parents infectes ont ete testees par ELISA, jusqu'a 30 % des plantes etaient infectees par le CMV. L'evaluation de L'ELISA pour la detection du CMV chez le niebe a revele que la concentration du virus etait la plus elevee dans les fleurs et le plus faible dans les feuilles primaires. Afin d'evaluer la capacite d'ELISA de detecter CMV, le test serologique etait compare a la RT-PCR, ou l'ELISA s'est montre sensible et fiable pour la detection du CMV dans des tissus infectes. Pour l'analyse de semence, une methode non-destructive de detection de CMV basee sur le blotting de tissus d'hypocotyle etait developpe. (Af Crop Science and Production: 2001 9(4): 677-684)