Narvaez-Vasquez J, Florin-Christensen J, Ryan CA
Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA.
Plant Cell. 1999 Nov;11(11):2249-60. doi: 10.1105/tpc.11.11.2249.
Phospholipase A (PLA) activity, as measured by the accumulation of (14)C-lysophosphatidylcholine in leaves of tomato plants, increased rapidly and systemically in response to wounding. The increase in PLA activity in the systemic unwounded leaves was biphasic in wild-type tomato plants, peaking at 15 min and again at 60 min, but the second peak of activity was absent in transgenic prosystemin antisense plants. Supplying young excised tomato plants with the polypeptide hormone systemin also caused (14)C-lysophosphatidylcholine to increase to levels similar to those induced by wounding, but the increase in activity persisted for >2 hr. Antagonists of systemin blocked both the release of (14)C-lysophosphatidylcholine and the accumulation of defense proteins in response to systemin. (14)C-lysophosphatidylcholine levels did not increase in response to jasmonic acid. Chemical acylation of the lysophosphatidylcholine produced by wounding, systemin, and oligosaccharide elicitors followed by enzymatic hydrolysis with lipases of known specificities demostrated that the lysophosphatidylcholine is generated by a PLA with specificity for the sn-2 position.
通过测量番茄植株叶片中（14）C-溶血磷脂酰胆碱的积累来测定的磷脂酶A（PLA）活性，在受到创伤后迅速且系统性地增加。在野生型番茄植株中，未受伤的系统性叶片中PLA活性的增加呈双相性，在15分钟时达到峰值，60分钟时再次达到峰值，但在转基因原系统素反义植株中没有第二个活性峰值。给切除的幼嫩番茄植株供应多肽激素系统素也会导致（14）C-溶血磷脂酰胆碱增加到与创伤诱导的水平相似，但活性增加持续超过2小时。系统素拮抗剂可阻断（14）C-溶血磷脂酰胆碱的释放以及防御蛋白对系统素的积累反应。（14）C-溶血磷脂酰胆碱水平对茉莉酸没有增加反应。对由创伤、系统素和寡糖激发子产生的溶血磷脂酰胆碱进行化学酰化，然后用已知特异性的脂肪酶进行酶促水解，结果表明溶血磷脂酰胆碱是由对sn-2位具有特异性的PLA产生的。
