Nitrogen availability alters patterns of accumulation of heat stress-induced proteins in plants
Nitrogen availability alters patterns of accumulation of heat stress-induced proteins in plants
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DOI：
10.1007/bf00328745
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发表时间：
1996-02-01
期刊：
影响因子：
2.7
通讯作者：
Hallberg, RL
中科院分区：
文献类型：
--
作者：
Heckathorn, SA;Poeller, GJ;Hallberg, RL
越来越多的证据表明，热休克蛋白（HSPs）在提高高温下的生存能力方面起着至关重要的作用。然而，HSP产生的模式在物种之间，甚至在物种的个体之间和个体内存在相当大的差异。目前尚不清楚为什么存在这种差异，以及在何种程度上热休克蛋白在生物体之间的变化可能与耐热性的差异。一种可能性是热休克蛋白的生产带来了成本，自然选择已经朝着优化热休克蛋白合成和积累的成本效益的方向努力。然而，这一生产的成本尚未确定。如果HSP的产生会产生显著的氮（N）成本，那么我们推断在低氮条件下生长的植物可能比高氮植物积累更少的HSP。此外，如果热休克蛋白相关的耐热性，然后由N（或其他因素）诱导的热休克蛋白的变化可能与耐热性的变化，在这里测量的净CO2同化和光系统LI（PSII）功能的热应激的短期影响。为了测试这些预测，我们种植了一个单一品种的玉米（玉米L。）在不同的氮水平下，然后将植物暴露于急性热胁迫。我们发现：（1）高氮植株每单位蛋白产生的线粒体Hsp 60和叶绿体Hsp 24的量高于低氮植株;（2）HSP的产生模式与PSII效率（F-v/F-m）相关。因此，我们的研究结果表明，氮的可利用性影响高等植物中HSP的产生，这表明HSP的产生可能是资源有限的，并且除了其他益处之外，叶绿体HSP（例如，热休克蛋白24）可能在某种程度上限制损害PSII功能在热应激。
Mounting evidence suggests that heat-shock proteins (HSPs) play a vital role in enhancing survival at high temperature. There is, however, considerable variation in patterns of HSP production among species, and even among and within individuals of a species. It is not known why this variation exists and to what extent variation in HSPs among organisms might be related to differences in thermotolerance. One possibility is that production of HSPs confers costs and natural selection has worked towards optimizing the cost-to-benefits of HSP synthesis and accumulation. However, the costs of this production have not been determined. If HSP production confers significant nitrogen (N) costs, then we reasoned that plants grown under low-N conditions might accumulate less HSP than high-N plants. Furthermore, if HSPs are related to thermotolerance, then variation in HSPs induced by N (or other factors) might correlate with variation in thermotolerance, here measured as short-term effects of heat stress on net CO2 assimilation and photosystem LI (PSII) function. To test these predictions, we grew individuals of a single variety of corn (Zea mays L.) under different N levels and then exposed the plants to acute heat stress. We found that: (1) high-N plants produced greater amounts of mitochondrial Hsp60 and chloroplastic Hsp24 per unit protein than their low-N counterparts; and (2) patterns of HSP production were related to PSII efficiency, as measured by F-v/F-m. Thus, our results indicate that N availability influences HSP production in higher plants suggesting that HSP production might be resource-limited, and that among other benefits, chloroplast HSPs (e.g., Hsp24) may in some way limit damage to PSII function during heat stress.