Melatonin attenuates postharvest physiological deterioration of cassava storage roots
Melatonin attenuates postharvest physiological deterioration of cassava storage roots
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褪黑激素减轻木薯贮藏根采后的生理恶化
DOI：
10.1111/jpi.12325
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发表时间：
2016-05-01
影响因子：
10.3
通讯作者：
Wang, Zhen-Yu
中科院分区：
文献类型：
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作者：
Ma, Qiuxiang;Zhang, Ting;Wang, Zhen-Yu
据报道，褪黑素提高了植物的非生物和生物逆境耐受性，但关于其在木薯采后生理恶化(PPD)期间的体内影响的信息有限。在本研究中，我们研究了褪黑素对木薯PPD的调节作用。500 mg/L褪黑激素处理显著延缓了木薯PPD的进程，减少了过氧化氢的积累，提高了超氧化物歧化酶、过氧化氢酶和谷胱甘肽还原酶的活性，但对抗坏血酸过氧化物酶的作用不明显。进一步的转录分析表明，经500 mg/L褪黑素处理的木薯切片中铜/锌超氧化物歧化酶(Mecu/ZnSOD)、MeCAT1、谷胱甘肽过氧化物酶(MeGPX)、过氧化物酶3(MePX3)和谷胱甘肽-S转移酶(MeGST)的表达高于未处理的木薯。这些数据表明，褪黑素通过直接或间接维持细胞内活性氧物种(ROS)的动态平衡来延迟木薯PPD。我们还发现，内源褪黑素的积累和褪黑素生物合成基因的转录水平在PPD过程中发生了动态变化。这一发现表明，内源褪黑素在维持木薯PPD进程中起着信号调制器的作用，通过基因工程操纵褪黑素生物合成基因可能防止木薯根的退化。
Melatonin reportedly increases abiotic and biotic stress tolerance in plants, but information on its in vivo effects during postharvest physiological deterioration (PPD) in cassava is limited. In this study, we investigated the effect of melatonin in regulating cassava PPD. Treatment with 500 mg/L melatonin significantly delayed cassava PPD and reduced the accumulation of hydrogen peroxide (H2O2) while increasing the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), but not ascorbate peroxidase (APX). Transcript analysis further showed that expression of copper/zinc SOD (MeCu/ZnSOD), MeCAT1, glutathione peroxidase (MeGPX), peroxidase 3 (MePX3), and glutathione S‐transferases (MeGST) was higher in cassava roots sliced treated with 500 mg/L melatonin than in those not exposed to exogenous melatonin. These data demonstrate that melatonin delays cassava PPD by directly or indirectly maintaining homoeostasis of cellular reactive oxygen species (ROS). We also found that accumulation of endogenous melatonin and the transcript levels of melatonin biosynthesis genes changed dynamically during the PPD process. This finding suggested that endogenous melatonin acts as a signal modulator for maintaining cassava PPD progression and that manipulation of melatonin biosynthesis genes through genetic engineering might prevent cassava root deterioration.