Hahn M, Neef U, Struck C, Göttfert M, Mendgen K
Fakultät für Biologie, Universität Konstanz, Germany.
Mol Plant Microbe Interact. 1997 May;10(4):438-45. doi: 10.1094/MPMI.1997.10.4.438.
A cDNA library constructed from haustoria of the rust fungus Uromyces fabae was screened for clones that are differentially expressed in haustoria. One family of cDNAs (in planta-induced gene 2 [PIG2] was isolated and found to encode a protein with high homologies to fungal amino acid transporters. A cDNA clone containing the complete coding region of PIG2 and the corresponding genomic clone were isolated and sequenced, revealing the presence of 17 introns in the PIG2 gene. Expression of PIG2 mRNA appeared to be restricted to haustoria. With antibodies raised against synthetic peptides, the PIG2-encoded protein was found in membranes fractions of isolated haustoria but not of germinated rust spores. With immunofluorescence microscopy, the putative amino acid transporter was localized to plasma membranes of the haustorial bodies, but not detected in the haustorial neck, haustorial mother cells, or intercellular fungal hyphae growing within infected leaf tissue. These data present for the first time molecular evidence that the rust haustorium plays a special role in the uptake of nutrients from an infected host cell.
从豆类锈菌吸器构建的cDNA文库中筛选在吸器中差异表达的克隆。分离出一个cDNA家族（植物诱导基因2 [PIG2]），发现其编码一种与真菌氨基酸转运蛋白具有高度同源性的蛋白质。分离并测序了一个包含PIG2完整编码区的cDNA克隆和相应的基因组克隆，揭示PIG2基因中存在17个内含子。PIG2 mRNA的表达似乎仅限于吸器。用针对合成肽产生的抗体，在分离的吸器的膜部分中发现了PIG2编码的蛋白质，但在萌发的锈孢子中未发现。通过免疫荧光显微镜观察，推测的氨基酸转运蛋白定位于吸器体的质膜，但在吸器颈部、吸器母细胞或感染叶片组织内生长的细胞间真菌菌丝中未检测到。这些数据首次提供了分子证据，表明锈菌吸器在从受感染宿主细胞摄取营养方面发挥特殊作用。
