Regulation of Plant Respiration: Genetics, Biochemistry, and Biophysics

与其他生物不同，9407979种麦金托什植物有两条呼吸途径：“正常”细胞色素途径和“替代途径”。这一点很重要，因为替代途径的呼吸作用不会导致跨内线粒体膜的质子梯度，因此顺着这条途径流动的电子不会保存能量。显然，所有植物都包含另一种呼吸途径，这种呼吸途径可能是对发育信号(如碳水化合物状态增加和开花)和许多环境刺激(如寒冷、伤害和内源水杨酸浓度)的反应而诱导的。为什么植物应该有一个比大多数其他真核生物更复杂的呼吸系统？它的功能是什么？虽然目前还不可能形成一个完整的答案，但替代途径呼吸很可能参与调节植物的能量/碳平衡，以响应不同的发育和环境需求。剖析任何途径的重要性和功能的一个经典方法是研究该途径中的突变。没有植物突变体被分离出来用于替代途径的呼吸，可能是因为它被认为具有调节功能。本研究提出的方法是建立细胞色素氧化酶和交替氧化酶含量改变的植物品系，并利用这些品系来阐明植物呼吸能量平衡的遗传、生化和生物物理调节。番茄和土豆植物将被用作实验系统。***

9407979 McIntosh Plants, unlike other organisms, possess two respiratory pathways: the "normal" cytochrome pathway and an "alternative pathway". This is important because alternative pathway respiration does not contribute to a proton gradient across the inner mitochondrial membrane and thus electrons that flow down this pathway do not conserve energy. All plants apparently contain an alternative pathway of respiration, that may be induced in response to developmental signals (such as increased carbohydrate status and flowering) and many environmental stimuli (such as cold, wounding, and endogenous salicylic acid concentrations). Why should plants have a more complex respiratory system than most other eukaryotes and what is its funciton? Although it is not possible to form a complete answer now, alternative pathway respiration is most probably involved in the regulation of energy/carbon balance in plants in response to varying demands of development and the environment. A classic approach to dissect the importance and function of any pathway is to study mutants in the pathway. No plant mutants have been isolated for alternative pathway respiration, possibly because of its proposed regulatory functions. The approach put forward in this research is to create plant lines with altered amounts of cytochrome oxidase and alternative oxidase, and to use these lines to elucidate the genetic, biochemical, and biophysical regulation of respiratory energy balance in plants. Tomato and potato plants will be used as experimental systems. ***