Wang D, Maule A J
Department of Virus Research, John Innes Institute, Norwich, U.K.
J Gen Virol. 1992 Jul;73 ( Pt 7):1615-20. doi: 10.1099/0022-1317-73-7-1615.
Seed transmission of an isolate of pea seed-borne mosaic virus (PSbMV) in several pea genotypes has been studied. Cross-pollination experiments showed that pollen transmission of PSbMV did not occur and accordingly, virus was not detected in pollen grains by ELISA or electron microscopy. Comparative studies between two pea cultivars, one with a high incidence of seed transmission and one with none, showed that PSbMV infected the floral tissues (sepals, petals, anther and carpel) of both cultivars, but was not detected in ovules prior to fertilization. Virus was detected equally well in seed coats of the progeny in both cultivars. Analysis of virus incidence and concentration in pea seeds of different developmental stages demonstrated that in the cultivar with a high incidence of seed transmission, PSbMV directly invaded immature embryos, multiplied in the embryonic tissues and persisted during seed maturation. In contrast, the cultivar without seed transmission did not show invasion of immature embryos by the virus; there was no evidence for virus multiplication or persistence during embryo development and seed maturation. Hence seed transmission of PSbMV resulted from direct invasion of immature pea embryos by the virus and the block to seed transmission in the non-permissive cultivar probably occurred at this step.
对豌豆种子传播花叶病毒（PSbMV）的一个分离株在几种豌豆基因型中的种子传播情况进行了研究。异花授粉实验表明，PSbMV不会通过花粉传播，因此，通过酶联免疫吸附测定（ELISA）或电子显微镜在花粉粒中均未检测到病毒。对两个豌豆品种进行比较研究，一个品种种子传播发生率高，另一个品种无种子传播，结果表明，PSbMV感染了两个品种的花组织（萼片、花瓣、花药和心皮），但在受精前的胚珠中未检测到病毒。在两个品种子代的种皮中均能很好地检测到病毒。对不同发育阶段豌豆种子中病毒发生率和浓度的分析表明，在种子传播发生率高的品种中，PSbMV直接侵入未成熟胚，在胚组织中增殖并在种子成熟过程中持续存在。相比之下，无种子传播的品种未显示病毒侵入未成熟胚；没有证据表明在胚发育和种子成熟过程中病毒有增殖或持续存在。因此，PSbMV的种子传播是由于病毒直接侵入未成熟豌豆胚所致，而在非允许品种中种子传播受阻可能发生在这一步骤。
