Sulphur supply and infection with Pyrenopeziza brassicae influence L-cysteine desulphydrase activity in Brassica napus L.
Sulphur supply and infection with Pyrenopeziza brassicae influence L-cysteine desulphydrase activity in Brassica napus L.
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DOI：
10.1093/jxb/erh236
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发表时间：
2004-10-01
影响因子：
6.9
通讯作者：
Schnug, E
中科院分区：
文献类型：
--
作者：
Bloem, E;Riemenschneider, A;Schnug, E
不同的田间调查表明，硫(S)肥能提高农作物对真菌病原菌的抗性。然而，硫磺诱导抗性(SIR)的机制尚不清楚。挥发性S化合物被认为发挥了重要作用，因为硫化氢对真菌有毒。通过田间试验，分析了S施肥量和过氧化氢释放酶活性对真菌侵染的影响。用L-半胱氨酸脱硫酶和O-乙酰-L-丝氨酸(硫醇)裂解酶的活性，研究了两种氮肥和两种施氮肥和两个油菜品种的释放H_2S的潜力。LCD在半胱氨酸降解过程中释放H_2S，而OAS-TL在半胱氨酸合成过程中消耗H_2S，而游离H_2S仅在副反应中释放。田间试验的所有小区都显示有白粉病的侵染，并从明显受感染的叶区和明显未受侵染的叶区采集叶盘样本，以调查与处理有关的对感染的反应。测定不同S组分的液晶屏和OAS-TL活性，以评估S营养和真菌感染与其释放H_2S的潜力。施用S显著提高了植株体内总S、硫酸盐、有机S、半胱氨酸和谷胱甘肽的含量，降低了液晶屏的活性。侵染甘蓝型油菜后，半胱氨酸和谷胱甘肽含量增加，LCD活性增加。因此，作物能够对真菌感染做出反应，释放H_2S的可能性更大，这反映在LCD活性随着真菌感染而增加。
Different field surveys have shown that sulphur (S) fertilization can increase the resistance of agricultural crops against fungal pathogens. The mechanisms of this sulphur-induced resistance (SIR) are, however, not yet known. Volatile S compounds are thought to play an important role because H2S is toxic to fungi. A field experiment was conducted to analyse the influence of S fertilization and the activity of H2S-releasing enzymes on fungal infections. Two levels of N and S fertilizers and two varieties of oilseed rape were investigated with respect to their potential to release H2S by the enzymatic activity of L-cysteine desulphydrase (LCD) and O-acetyl-L-serine(thiol)lyase (OAS-TL). LCD releases H2S during cysteine degradation, while OAS-TL consumes H2S during cysteine synthesis and free H2S is only released in a side reaction. All plots of the field trial showed an infection with Pyrenopeziza brassicae and leaf disc samples were taken from visibly infected leaf areas and apparently uninfected areas to investigate the reaction to the infection in relation to the treatments. Different S fractions and the activities of LCD and OAS-TL were measured to evaluate the potential to release H2S in relation to S nutrition and fungal infection. S fertilization significantly increased the contents of total S, sulphate, organic S, cysteine, and glutathione in the plants, but decreased LCD activity. Infection with P. brassicae increased cysteine and glutathione contents, as well as the activity of LCD. Therefore crops were able to react to a fungal infection with a greater potential to release H2S, which is reflected by an increasing LCD activity with fungal infection.