Overexpression of MpCYS4, a phytocystatin gene from Malus prunifolia (Willd.) Borkh., delays natural and stress-induced leaf senescence in apple
Overexpression of MpCYS4, a phytocystatin gene from Malus prunifolia (Willd.) Borkh., delays natural and stress-induced leaf senescence in apple
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MpCYS4（一种来自Malus prunifolia (Willd.) Borkh.的植物胱抑素基因）的过度表达可延迟苹果自然和胁迫诱导的叶片衰老
DOI：
10.1016/j.plaphy.2017.03.025
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发表时间：
2017
影响因子：
6.5
通讯作者：
Ma Fengwang
中科院分区：
文献类型：
--
作者：
Tan Yanxiao;Yang Yingli;Li Chao;Liang Bowen;Li Mingjun;Ma Fengwang
植物胱抑素是一类具有良好特征的天然蛋白酶抑制剂，可阻止木瓜蛋白酶样半胱氨酸蛋白酶的催化作用。胱抑素在植物抗逆性中的作用已被广泛研究，但对其在植物叶片衰老过程中的作用却知之甚少。在这里，我们研究了苹果胱抑素MpCYS4在叶片光合作用中的潜在作用，以及当植物遭遇自然或应激诱导的衰老时叶片蛋白质的浓度和组成。该基因在苹果砧木M26中的过表达可有效减缓衰老相关的光合活性和叶绿素浓度下降，并阻止半胱氨酸蛋白酶在衰老叶片中降解蛋白质（如Rubisco）过程中的作用。此外，mpcys4通过激活抗坏血酸过氧化物酶、过氧化物酶和过氧化氢酶等抗氧化酶，减轻了相关的氧化损伤，增强了植物清除活性氧的能力。因此，植物细胞在叶片衰老过程中免受自由基的伤害。综上所述，mpcys4具有延缓苹果叶片自然衰老和应激衰老的作用。
Phytocystatins are a well-characterized class of naturally occurring protease inhibitors that prevent the catalysis of papain-like cysteine proteases. The action of cystatins in stress tolerance has been studied intensively, but relatively little is known about their functions in plants during leaf senescence. Here, we examined the potential roles of the apple cystatin,MpCYS4, in leaf photosynthesis as well as the concentrations and composition of leaf proteins when plants encounter natural or stress-induced senescence. Overexpression of this gene in apple rootstock M26 effectively slowed the senescence-related declines in photosynthetic activity and chlorophyll concentrations and prevented the action of cysteine proteinases during the process of degrading proteins (e.g., Rubisco) in senescing leaves. Moreover,MpCYS4alleviated the associated oxidative damage and enhanced the capacity of plants to eliminate reactive oxygen species by activating antioxidant enzymes such as ascorbate peroxidase, peroxidase, and catalase. Consequently, plant cells were protected against damage from free radicals during leaf senescence. Based on these results, we conclude thatMpCYS4functions in delaying natural and stress-induced senescence of apple leaves.