Dodds P N, Clarke A E, Newbigin E
Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria, Australia.
Plant Mol Biol. 1996 May;31(2):227-38. doi: 10.1007/BF00021786.
We characterised a cDNA encoding an S-like RNase (RNase NE) from the styles of the self-incompatible plant, Nicotiana alata. RNase NE is 86% identical to an extracellular RNase from tomato cell cultures, RNase LE. DNA hybridisation experiments indicate that there are ca. 5-6 sequences related to RNase NE in the N. alata genome and that RNase NE is not linked to the self-incompatibility (S) locus. RNase NE is expressed in the styles, petals and immature anthers but not in the vegetative tissues of N. alata plants under normal growth conditions. Under phosphate-limited conditions, RNase NE expression is induced in roots but not leaves of N. alata. A transcript hybridising to RNase NE is also induced in N. plumbaginifolia cell cultures in response to phosphate starvation. RNase NE is likely to play a role in the response of N. alata to phosphate limitation, possibly by scavenging phosphate from sources of RNA in the root environment. We also discuss the evolutionary relationships between the S- and S-like RNase genes in plants.
我们对来自自交不亲和植物烟草花柱中一个编码S类核糖核酸酶（核糖核酸酶NE）的cDNA进行了特性分析。核糖核酸酶NE与番茄细胞培养物中的一种细胞外核糖核酸酶核糖核酸酶LE有86%的同源性。DNA杂交实验表明，烟草基因组中约有5 - 6个与核糖核酸酶NE相关的序列，且核糖核酸酶NE与自交不亲和（S）位点没有连锁关系。在正常生长条件下，核糖核酸酶NE在烟草的花柱、花瓣和未成熟花药中表达，但在营养组织中不表达。在磷限制条件下，核糖核酸酶NE的表达在烟草的根中被诱导，但在叶中未被诱导。在蓝烟草细胞培养物中，响应磷饥饿也会诱导一个与核糖核酸酶NE杂交的转录本。核糖核酸酶NE可能在烟草对磷限制的响应中发挥作用，可能是通过从根环境中的RNA来源清除磷来实现。我们还讨论了植物中S类和S类核糖核酸酶基因之间的进化关系。
