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Journal of Zhejiang University SCIENCE B
ISSN 1673-1581(Print), 1862-1783(Online), Monthly
2016 Vol.17 No.12 P.916-930
Nitric oxide induced by polyamines involves antioxidant systems against chilling stress in tomato (Lycopersicon esculentum Mill.) seedling
Abstract: Polyamines (PAs) and nitric oxide (NO) are vital signals in modulating plant response to abiotic stress. However, to our knowledge, studies on the relationship between NO and PAs in response to cold stress in tomato are limited. Accordingly, in this study, we investigated the effects of putrescine (Put) and spermidine (Spd) on NO generation and the function of Spd-induced NO in the tolerance of tomato seedling under chilling stress. Spd increased NO release via the nitric oxide synthase (NOS)-like and nitrate reductase (NR) enzymatic pathways in the seedlings, whereas Put had no such effect. Moreover, H2O2 might act as an upstream signal to stimulate NO production. Both exogenous NO donor (sodium nitroprusside (SNP)) and Spd enhanced chilling tolerance in tomato, thereby protecting the photosynthetic system from damage. Compared to chilling treatment alone, Spd enhanced the gene expressions of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), and their enzyme activities in tomato leaves. However, a scavenger or inhibitor of NO abolished Spd-induced chilling tolerance and blocked the increased expression and activity due to Spd of these antioxidant enzymes in tomato leaves under chilling stress. The results showed that NO induced by Spd plays a crucial role in tomato’s response to chilling stress.
Key words: Antioxidant enzymes, Chilling tolerance, Hydrogen peroxide, Nitric oxide, Spermidine, Tomato
创新点：在番茄幼苗中证明亚精胺（Spd）对NO产生的影响及可能的作用途径，且此作用与番茄耐低温性有密切关系。
方法：通过检测氧合血红蛋白（HbO2）向高铁血红蛋白（metHb）的转化进行NO含量测定；通过与NO特异性荧光探针（DAF-FM DA）结合检测NO释放量（图1和2）。超氧化物歧化酶（SOD）活性根据其抑制氮蓝四唑（NBT）在光下的还原作用测定；过氧化物酶（POD）活性通过测定酶提取液与愈创木酚、过氧化氢（H2O2）的混合物的吸光度确定；过氧化氢酶（CAT）活性根据H2O2在240 nm波长下的降解能力来测定；抗坏血酸过氧化物酶（APX）活性的测定参照Nakano和Asada（1981）的方法在波长290 nm下测定（图6和7）。
结论：本研究的结果显示，Spd诱导番茄叶片中NO的产生可直接通过增加一氧化氮合酶（NOS）和硝酸还原酶（NR）的活性实现（图2）。H2O2作为上游信号能够刺激NO的生成（图3）。NO通过增加抗氧化酶活性和相关基因的表达来参与Spd诱导的番茄耐冷性（图6和7）。综上所述，Spd诱导产生的NO在番茄响应低温胁迫中发挥重要作用。
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DOI:
10.1631/jzus.B1600102
CLC number:
S641.2
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On-line Access:
2016-12-05
Received:
2016-03-04
Revision Accepted:
2016-05-20
Crosschecked:
2016-11-07