Identification of 33 rice aquaporin genes and analysis of their expression and function
Identification of 33 rice aquaporin genes and analysis of their expression and function
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DOI：
10.1093/pcp/pci172
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发表时间：
2005-09-01
影响因子：
4.9
通讯作者：
Maeshima, M
中科院分区：
文献类型：
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作者：
Sakurai, J;Ishikawa, F;Maeshima, M
植物水通道蛋白（aquaporins）包括质膜型水通道蛋白（PlPs）和液泡膜型水通道蛋白（TIPs），其主要生理功能是促进水分的跨膜渗透运输。我们在水稻基因组序列中鉴定了33个水通道蛋白基因。CV. Nipponbare）。我们研究了它们在水稻叶片、根和花药中的表达水平。Akitakomachi），使用半定量逆转录-PCR（RT-PCR）。在分蘖前期（萌发后21 d）和成穗期（56 d），OsPIP 2;4和OsPIP 2;5等6个基因主要在根中表达，OsPIP 2;7和OsTIP 1;2等14个基因在叶片中表达。OsPIP 1;1和OsTIP 4;1等8个基因在叶片、根和花药中均表达。通过停流分光光度法分析显示，当OsPIP 2;4或OsPIP 2;5在酵母中表达时，水通道活性高，而当OsPIP 1;1或OsPIP 1;2在酵母中表达时，水通道活性低。此外，OsPIP 2;4和OsPIP 2;5的mRNA水平在根中表现出明显的昼夜波动，在光照开始后3 h达到峰值，在黑暗开始后3 h降至最低。OsPIP 2;4和OsPIP 2;5等10个基因的mRNA水平在低温处理时显著下降，升温后恢复。低温处理期间和处理后mRNA水平的变化与伤流液量的变化相当。这些结果表明，OsPIP 2;4和OsPIP 2;5等几种具有高水通道活性的水通道蛋白的mRNA水平与根系吸水之间存在一定的关系。
Plant aquaporins form a large protein family including plasma membrane-type (PlPs) and tonoplast-type aquaporins (TIPs), and facilitate osmotic water transport across membranes as a key physiological function. We identified 33 genes for aquaporins in the genome sequence of rice (Oryza sativa L. cv. Nipponbare). We investigated their expression levels in leaf blades, roots and anthers of rice (cv. Akitakomachi) using semi-quantitative reverse transcription-PCR (RT-PCR). At both early tillering (21 d after germination) and panicle formation (56 d) stages, six genes, including OsPIP2;4 and OsPIP2;5, were expressed predominantly in roots, while 14 genes, including OsPIP2;7 and OsTIP1;2, were found in leaf blades. Eight genes, such as OsPIP1;1 and OsTIP4;1, were evenly expressed in leaf blades, roots and anthers. Analysis by stopped-flow spectrophotometry revealed high water channel activity when OsPIP2;4 or OsPIP2;5 were expressed in yeast but not when OsPIP1;1 or OsPIP1;2 were expressed. Furthermore, the mRNA levels of OsPIP2;4 and OsPIP2;5 showed a clear diurnal fluctuation in roots; they showed a peak 3 h after the onset of light and dropped to a minimum 3 h after the onset of darkness. The mRNA levels of 10 genes including OsPIP2;4 and OsPIP2;5 markedly decreased in roots during chilling treatment and recovered after warming. The changes in mRNA levels during and after the chilling treatment were comparable with that of the bleeding sap volume. These results suggested the relationship between the root water uptake and mRNA levels of several aquaporins with high water channel activity, such as OsPIP2;4 and OsPIP2;5.