Effects of Calcium and Calmodulin Antagonists on Chilling Stress-Induced Proline Accumulation in Jatropha curcas L.
Effects of Calcium and Calmodulin Antagonists on Chilling Stress-Induced Proline Accumulation in Jatropha curcas L.
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DOI：
10.1007/s00344-016-9584-3
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发表时间：
2016-02
影响因子：
4.8
通讯作者：
Shuang-Long Yang;Shan Lan;F. Deng;M. Gong
中科院分区：
文献类型：
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作者：
Shuang-Long Yang;Shan Lan;F. Deng;M. Gong
植物在低温胁迫下的脯氨酸积累调控尚不清楚。采用外源氯化钙(CaCl2)、质膜钙通道阻断剂氯化镧(LaCl3)、钙调素拮抗剂氯丙嗪(CPZ)和三氟拉嗪(TFP)处理低温胁迫麻疯树幼苗，研究了钙和钙调素(CaM)对Pro积累和耐冷性的影响。结果表明，CaCl2处理显著增强了冷害诱导的脯氨酸积累。CaCl2还诱导了谷氨酸合成途径中的关键酶Δ1-吡咯啉-5-羧酸合成酶(P5CS)和谷氨酸脱氢酶(GDH)活性的几乎立即和快速的增加，并上调了P5CS的表达，但它降低了Pro降解的关键酶PROH的活性，并抑制了PROSH的表达。LaCl3、CPZ和TFP处理的效果与CaCl2处理的相反。此外，CaCl2、LaCl3、CPZ和TFP对鸟氨酸生物合成途径中的关键酶鸟氨酸转氨酶和精氨酸酶的活性影响不大。这些结果表明，Ca~(2+)-CaM可能参与了信号转导过程，导致了低温胁迫下魔芋幼苗中Pro的积累，而Ca~(2+)诱导的Pro的积累是激活了Pro生物合成的谷氨酸途径和同时抑制了Pro的降解途径的共同结果。此外，在低温胁迫下，CaCl2处理提高了魔芋幼苗的组织活力，降低了膜脂过氧化产物丙二醛(MDA)的含量，减轻了电解质渗漏，表明外源Ca~(2+)可以提高植物的耐冷性，而脯氨酸可能是提高耐冷性的关键因素。
Regulation of proline accumulation in plants under chilling stress remains unclear. In this paper, we treated Jatropha curcas seedlings under chilling stress with exogenous calcium chloride (CaCl2), the plasma membrane Ca2+-channel blocker lanthanum chloride (LaCl3), calmodulin antagonists, chlorpromazine (CPZ), and trifluoperazine (TFP) and investigated the effects of calcium and calmodulin (CaM) on proline accumulation and chilling tolerance. The results showed that CaCl2 treatment significantly enhanced chilling stress-induced proline accumulation. CaCl2 also induced an almost immediate and rapid increase of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and glutamate dehydrogenase activities, the key enzymes in the glutamate pathway of proline biosynthesis, and up-regulated P5CS expression, but it decreased the activity of proline dehydrogenase (ProDH), a key enzyme of proline degradation, and inhibited ProDH expression. Treatment with LaCl3, CPZ, and TFP exhibited the opposite effects to those by CaCl2 treatment. Moreover, CaCl2, LaCl3, CPZ, and TFP had little effect on the activities of ornithine aminotransferase and arginase, the key enzymes in the ornithine pathway of proline biosynthesis. These results indicated that Ca2+-CaM might be involved in signal transduction events, leading to proline accumulation in J. curcas seedlings under chilling stress, and that Ca2+-induced proline accumulation is a combined result of the activation of the glutamate pathways of proline biosynthesis and the simultaneous inhibition of the proline degradation pathway. In addition, CaCl2 treatment increased tissue vitality, decreased the content of the lipid peroxidation product malondialdehyde (MDA), and alleviated electrolyte leakage in J. curcas seedlings under chilling stress, indicating that exogenous Ca2+ can enhance chilling tolerance, and proline might be a key factor in this increased chilling tolerance.