Okubara P A, Fujishige N A, Hirsch A M, Berry A M
Department of Environmental Horticulture, University of California, Davis, California 95616, USA.
Plant Physiol. 2000 Apr;122(4):1073-9. doi: 10.1104/pp.122.4.1073.
We have isolated a 590-bp full-length cDNA clone designated Dg93, an mRNA that is highly expressed in symbiotic root nodules of the actinorhizal host Datisca glomerata. Dg93 mRNA encodes a deduced polypeptide of 105 amino acids with significant identity (74%) to the soybean (Glycine max) early nodulin (ENOD) gene GmENOD93 (Kouchi and Hata, 1993). Dg93 mRNA is abundant in nodules at 4 weeks post inoculation, the earliest time assayed, and steady-state mRNA levels remain elevated 11 weeks after inoculation. Spatial patterns of Dg93 mRNA expression are complex, with transcript accumulation in the nodule lobe meristem, early infection zone, periderm, and cells of the vascular cylinder, but not in the surrounding uninfected cortical cells. Dg93 is encoded by a small gene family in D. glomerata. To our knowledge, this is the first report of a gene from an actinorhizal host that is expressed in the nodule meristem and that shares sequence homology with an early nodulin gene from a legume.
我们分离出了一个590个碱基对的全长cDNA克隆，命名为Dg93，它是一种在放线菌根宿主球果达蒂斯卡共生根瘤中高度表达的mRNA。Dg93 mRNA编码一个由105个氨基酸组成的推导多肽，与大豆（Glycine max）早期结瘤素（ENOD）基因GmENOD93具有显著的同源性（74%）（Kouchi和Hata，1993年）。Dg93 mRNA在接种后4周（检测的最早时间）的根瘤中大量存在，接种后11周稳态mRNA水平仍保持升高。Dg93 mRNA表达的空间模式很复杂，转录本在根瘤叶分生组织、早期感染区、周皮和维管束细胞中积累，但在周围未感染的皮层细胞中不积累。Dg93由球果达蒂斯卡中的一个小基因家族编码。据我们所知，这是关于放线菌根宿主中一个在根瘤分生组织中表达且与豆科植物早期结瘤素基因具有序列同源性的基因的首次报道。
