Judelson H S, Whittaker S L
Department of Plant Pathology, University of California, Riverside 92521, USA.
Curr Genet. 1995 Nov;28(6):571-9. doi: 10.1007/BF00518171.
The mitotic and meiotic stabilities of transgenes were evaluated in the oomycete, Phytophthora infestans. Genes encoding beta-glucuronidase (GUS), neomycin phosphotransferase (NPT) and hygromycin phosphotransferase (HPT), fused to one of six promoters from P. infestans or other oomycetes, were usually stably expressed during continued asexual culture and transmitted to progeny. However, the activity of these genes became undetectable in many strains during asexual or sexual propagation. Over 33 months of growth, transgene expression stopped each month in 1-3% of the transformants. Silencing of the genes was not associated with their deletion, mutation, or hypermethylation. The conformation of the integrated sequences was similar in strains destined to continue or terminate expression of the transgenes. Expression of the genes was not associated with a loss of fitness during growth in vitro and in planta, which might otherwise have selected for silencing events.
在卵菌致病疫霉中评估了转基因的有丝分裂和减数分裂稳定性。编码β-葡萄糖醛酸酶（GUS）、新霉素磷酸转移酶（NPT）和潮霉素磷酸转移酶（HPT）的基因，与来自致病疫霉或其他卵菌的六个启动子之一融合，在持续的无性培养过程中通常稳定表达并传递给后代。然而，在无性或有性繁殖过程中，这些基因的活性在许多菌株中变得无法检测到。在超过33个月的生长过程中，每月有1-3%的转化体中转基因表达停止。基因沉默与它们的缺失、突变或超甲基化无关。在注定继续或终止转基因表达的菌株中，整合序列的构象相似。这些基因的表达与体外和植物体内生长期间的适应性丧失无关，否则可能会选择沉默事件。
