Zhu B, Chen T H, Li P H
Department of Horticultural Sciences, University of Minnesota, St Paul 55108, USA.
Plant Physiol. 1995 Jul;108(3):929-37. doi: 10.1104/pp.108.3.929.
Osmotin-like proteins are encoded by at least six members of a multigene family in Solanum commersonii. A genomic clone (lambda pGEM2a-7) that contains two osmotin-like protein genes (OSML13 and OSML81) arranged in the same transcriptional orientation has been isolated. Restriction mapping and sequence analysis indicated that the two intronless genes correspond to the previously characterized pA13 and pA81 cDNAs. To study the transcriptional activation of OSML13 and OSML81 promoters, the 5' flanking DNA sequence (-1078 to +35 of OSML13 and -1054 to +41 of OSML81) was fused to the beta-glucoronidase (GUS) coding region, and the chimeric gene fusions were introduced into wild potato (S. commersonii) plants via Agrobacterium-mediated transformation. Analysis of the chimeric gene expression in transgenic potato plants showed that both 5' flanking DNA sequences are sufficient to impart GUS inducibility by abscisic acid, NaCl, salicylic acid, wounding, and fungal infection. Low temperature activated both chimeric genes only slightly. Infection with Phytophthora infestans resulted in strong GUS expression from both chimeric genes primarily in the sites of pathogen invasion, suggesting a limited diffusion of fungal infection-mediated signals. The expression patterns of both osmotin-like protein genes implicate their dual functions in osmotic stress and plant pathogen defense.
渗透素样蛋白由番茄的一个多基因家族中的至少六个成员编码。已分离出一个基因组克隆（λpGEM2a - 7），其包含两个以相同转录方向排列的渗透素样蛋白基因（OSML13和OSML81）。限制性图谱分析和序列分析表明，这两个无内含子基因分别对应于先前鉴定的pA13和pA81 cDNA。为了研究OSML13和OSML81启动子的转录激活，将5'侧翼DNA序列（OSML13的 - 1078至 + 35以及OSML81的 - 1054至 + 41）与β - 葡萄糖醛酸酶（GUS）编码区融合，并通过农杆菌介导的转化将嵌合基因融合体导入野生马铃薯（番茄）植株中。对转基因马铃薯植株中嵌合基因表达的分析表明，两个5'侧翼DNA序列都足以赋予GUS受脱落酸、NaCl、水杨酸、创伤和真菌感染诱导的能力。低温仅轻微激活了两个嵌合基因。用致病疫霉感染导致两个嵌合基因主要在病原体入侵部位强烈表达GUS，这表明真菌感染介导的信号扩散有限。两个渗透素样蛋白基因的表达模式暗示了它们在渗透胁迫和植物病原体防御中的双重功能。
