Bargmann Bastiaan O R, Laxalt Ana M, ter Riet Bas, Testerink Christa, Merquiol Emmanuelle, Mosblech Alina, Leon-Reyes Antonio, Pieterse Corné M J, Haring Michel A, Heilmann Ingo, Bartels Dorothea, Munnik Teun
Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, NL, Amsterdam, the Netherlands.
Plant Cell Environ. 2009 Jul;32(7):837-50. doi: 10.1111/j.1365-3040.2009.01962.x. Epub 2009 Feb 9.
Plants respond to wounding by means of a multitude of reactions, with the purpose of stifling herbivore assault. Phospholipase D (PLD) has previously been implicated in the wounding response. Arabidopsis (Arabidopsis thaliana) AtPLDalpha1 has been proposed to be activated in intact cells, and the phosphatidic acid (PA) it produces to serve as a precursor for jasmonic acid (JA) synthesis and to be required for wounding-induced gene expression. Independently, PLD activity has been reported to have a bearing on wounding-induced MAPK activation. However, which PLD isoforms are activated, where this activity takes place (in the wounded or non-wounded cells) and what exactly the consequences are is a question that has not been comprehensively addressed. Here, we show that PLD activity during the wounding response is restricted to the ruptured cells using (32)P(i)-labelled phospholipid analyses of Arabidopsis pld knock-out mutants and PLD-silenced tomato cell-suspension cultures. pldalpha1 knock-out lines have reduced wounding-induced PA production, and the remainder is completely eliminated in a pldalpha1/delta double knock-out line. Surprisingly, wounding-induced protein kinase activation, AtLOX2 gene expression and JA biosynthesis were not affected in these knock-out lines. Moreover, larvae of the Cabbage White butterfly (Pieris rapae) grew equally well on wild-type and the pld knock-out mutants.
植物通过多种反应对创伤作出响应，目的是抑制食草动物的攻击。磷脂酶D（PLD）此前已被认为与创伤反应有关。拟南芥（Arabidopsis thaliana）的AtPLDalpha1被认为在完整细胞中被激活，其产生的磷脂酸（PA）作为茉莉酸（JA）合成的前体，并且是创伤诱导基因表达所必需的。另外，据报道PLD活性与创伤诱导的MAPK激活有关。然而，哪些PLD亚型被激活、这种活性发生在何处（受伤细胞还是未受伤细胞中）以及具体后果是什么，这些问题尚未得到全面解决。在此，我们通过对拟南芥pld基因敲除突变体和PLD沉默的番茄细胞悬浮培养物进行（32）P（i）标记的磷脂分析，表明创伤反应期间的PLD活性仅限于破裂的细胞。pldalpha1基因敲除品系创伤诱导的PA产生减少，而在pldalpha1/delta双基因敲除品系中其余部分被完全消除。令人惊讶的是，这些基因敲除品系中创伤诱导的蛋白激酶激活、AtLOX2基因表达和JA生物合成并未受到影响。此外，菜粉蝶（Pieris rapae）幼虫在野生型和pld基因敲除突变体上生长得同样良好。
