Salicylate accumulation inhibits growth at chilling temperature in Arabidopsis
Salicylate accumulation inhibits growth at chilling temperature in Arabidopsis
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DOI：
10.1104/pp.104.041293
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发表时间：
2004-06-01
期刊：
影响因子：
7.4
通讯作者：
Mur, LAJ
中科院分区：
文献类型：
--
作者：
Scott, IM;Clarke, SM;Mur, LAJ
拟南芥在低温条件下的生长可能与其水杨酸（SA）水平有关。SA羟化酶NahG转基因植株在23℃时的生长速度与Col-0野生型相近，但在5℃时，两种基因型的生长速度均有所减慢。然而，在5℃时，NAG植株的相对生长率比Col-0高出约三分之一，因此，到2个月时，NahG植株通常要大2.7倍。这主要是由于NahG莲座叶片的细胞扩增较大。两种基因型的比叶面积和比叶面积保持相似。两种基因型在23℃时的净同化率相似，但在5℃时NahG的净同化率更高。叶绿素荧光测量结果显示，两种基因型的冷冻叶片均无PSII光损伤。5℃下的冷芽积累SA，尤其是葡萄糖化形式的SA。NahG枝条中SA在5℃时也表现出类似的趋势，但在极低水平。没有检测到儿茶酚作为NahG转基因产物的代谢物。我们还检测了5℃下SA信号和代谢突变体的生长和SA水平。部分sa不敏感的npr1突变体的生长表现介于NahG和Col-0之间，而缺乏sa的eds5突变体的生长表现与NAG相似。相比之下，cpr1突变体在5℃时积累了非常高的SA，其生长受到比野生型更大的抑制。在这两个温度下，cpr1是唯一的sa应答基因型，其氧化损伤（以硫代巴比妥酸反应物质测量）与野生型显著不同。
The growth of Arabidopsis plants in chilling conditions could be related to their levels of salicylic acid (SA). Plants with the SA hydroxylase NahG transgene grew at similar rates to Col-0 wild types at 23degreesC, and growth of both genotypes was slowed by transfer to 5degreesC. However, at 5degreesC, NAG plants displayed relative growth rates about one-third greater than Col-0, so that by 2 months NahG plants were typically 2.7-fold larger. This resulted primarily from greater cell expansion in NahG rosette leaves. Specific leaf areas and leaf area ratios remained similar in both genotypes. Net assimilation rates were similar in both genotypes at 23degreesC, but higher in NahG at 5degreesC. Chlorophyll fluorescence measurements revealed no PSII photodamage in chilled leaves of either genotype. Col-0 shoots at 5degreesC accumulated SA, particularly in glucosylated form. SA in NahG shoots showed similar tendencies at 5degreesC, but at greatly depleted levels. Catechol was not detected as a metabolite of the NahG transgene product. We also examined growth and SA levels in SA signaling and metabolism mutants at 5degreesC. The partially SA-insensitive npr1 mutant displayed growth intermediate between NahG and Col-0, while the SA-deficient eds5 mutant behaved like NAG. In contrast, the cpr1 mutant at 5degreesC accumulated very high levels of SA and its growth was much more inhibited than wild type. At both temperatures, cpr1 was the only SA-responsive genotype in which oxidative damage (measured as thiobarbituric acid-reactive substances) was significantly different from wild type.