Liu Ji Hong, Ban Yusuke, Wen Xiao-Peng, Nakajima Ikuko, Moriguchi Takaya
National Institute of Fruit Tree Science, Tsukuba, Ibaraki 305-8605, Japan.
Gene. 2009 Jan 15;429(1-2):10-7. doi: 10.1016/j.gene.2008.10.003. Epub 2008 Oct 22.
Arginine decarboxylase (ADC), one of the enzymes responsible for putrescine (Put) biosynthesis, has been shown to be implicated in stress response. In the current paper attempts were made to clone and characterize a gene encoding ADC from peach (Prunus persica (L.) Batsch, 'Akatsuki'). Rapid amplification of cDNA ends (RACE) gave rise to a full-length ADC cDNA (PpADC) with a complete open reading frame of 2178 bp, encoding a 725 amino acid polypeptide. Homology search and sequence multi-alignment demonstrated that the deduced PpADC protein sequence shared a high identity with ADCs from other plants, including several highly conservative motifs and amino acids. Southern blotting indicated that PpADC existed in peach genome as a single gene. Expression levels of PpADC in different tissues of peach (P. persica 'Akatsuki') were spatially and developmentally regulated. Treatment of peach shoots from 'Mochizuki' with exogenous 5 mM Put, an indirect product of ADC, remarkably induced accumulation of PpADC mRNA. Transcripts of PpADC in peach leaves from 'Mochizuki' were quickly induced, either transiently or continuously, in response to dehydration, high salinity (200 mM NaCl), low temperature (4 degrees C) and heavy metal (150 microM CdCl(2)), but repressed by high temperature 37 degrees C) during a 2-day treatment, which changed in an opposite direction when the stresses were otherwise removed with the exception of CdCl(2) treatment. In addition, steady-state of PpADC mRNA could be also transiently up-regulated by abscisic acid (ABA) in 'Mochizuki' leaves. All of these, taken together, suggest that PpADC is a stress-responsive gene and can be considered as a potential target that is genetically manipulated so as to create novel germplasms with enhanced stress tolerance in the future.
精氨酸脱羧酶（ADC）是负责腐胺（Put）生物合成的酶之一，已被证明与应激反应有关。在本论文中，我们尝试从桃（Prunus persica (L.) Batsch，‘明月’）中克隆并鉴定一个编码ADC的基因。通过cDNA末端快速扩增（RACE）获得了一个全长ADC cDNA（PpADC），其完整开放阅读框为2178 bp，编码一个725个氨基酸的多肽。同源性搜索和序列多重比对表明，推导的PpADC蛋白序列与其他植物的ADC具有高度同一性，包括几个高度保守的基序和氨基酸。Southern杂交表明PpADC在桃基因组中以单基因形式存在。桃（‘明月’）不同组织中PpADC的表达水平受到空间和发育调控。用外源5 mM Put（ADC的间接产物）处理‘望月’桃梢，显著诱导了PpADC mRNA的积累。‘望月’桃叶中PpADC的转录本在脱水、高盐（200 mM NaCl）、低温（4℃）和重金属（150 μM CdCl₂）处理下，无论是瞬时还是持续地迅速诱导，但在2天处理期间受到高温（37℃）抑制；当除CdCl₂处理外的其他胁迫解除时，情况则相反。此外，脱落酸（ABA）也可瞬时上调‘望月’叶片中PpADC mRNA的稳态水平。综上所述，这些结果表明PpADC是一个应激响应基因，可被视为未来通过基因操作创造具有增强胁迫耐受性的新型种质的潜在靶点。
