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硫化氢(H2S)是植物中最新发现的一种气体信号分子,高等植物中内源H2S主要由L-型半胱氨酸脱巯基酶(LCD)和D-型半胱氨酸脱巯基酶(DCD)两类蛋白产生。我们的前期研究结果表明外源H2S能够促进植物侧根发育。为了研究内源H2S的产生机制及H2S与一氧化氮(NO)在调控侧根发育中的作用,本实验以番茄幼苗为材料,克隆了编码H2S合成酶基因Sl_OASTL/LCD;研究抑制内源H2S对NO诱导侧根发育的影响;并研究了NO对Sl_OASTL/LCD表达的影响。结果显示:(1)番茄根中存在3个O-乙酰丝氨酸(硫醇)裂解酶基因(Sl_OASTL1、Sl_OASTL2、Sl_OASTL3)。比对和结构分析显示,Sl_OASTL1为编码H2S合成酶基因LCD,所以将Sl_OASTL1命名为Sl_OASTL/LCD;启动子区域分析显示,Sl_OASTL/LCD基因上游含有多个响应NO和植物激素信号的保守基序。(2)与对照相比,内源H2S合成酶抑制剂DL-炔丙基甘氨酸(PAG)和内源H2S清除剂亚牛磺酸(HT)处理均能抑制侧根生长。(3)外源NO供体硝普钠(SNP)显著诱导侧根生长。(4)PAG和HT处理均能够抑制NO对侧根生长的诱导作用。(5)RT-PCR分析显示,SNP处理能够显著诱导幼苗根中Sl_OASTL/LCD的表达。上述结果表明,NO可能通过调控Sl_OASTL/LCD的表达产生内源H2S诱导番茄幼苗侧根发育。
Hydrogen sulfide (H2S) is a recently discovered gas signaling molecule in plants. The endogenous H2S in higher plants is mainly composed of L-type cysteine desulfhydrylase (LCD) and D-type cysteine desulfhydrylase DCD) two types of protein production. Our previous results show that exogenous H2S can promote plant lateral root development. In order to study the mechanism of endogenous H2S production and the role of H2S and nitric oxide (NO) in the regulation of lateral root development, we cloned the gene Sl_OASTL / LCD encoding H2S synthase from tomato seedlings. NO induced lateral root development; and NO on Sl_OASTL / LCD expression. The results showed that: (1) There are three O-acetylserine (thiol) lyase genes (Sl_OASTL1, Sl_OASTL2, Sl_OASTL3) in tomato root. Therefore, Sl_OASTL1 was named Sl_OASTL / LCD. Promoter region analysis showed that there are many conserved motifs upstream of Sl_OASTL / LCD gene in response to NO and phytohormone signals. (2) Compared with the control, both endogenous H2S synthetase inhibitor DL-propargylglycine (PAG) and endogenous H2S scavenger hypotaurine (HT) could inhibit lateral root growth. (3) Exogenous nitric oxide donor nitroprusside (SNP) significantly induced lateral root growth. (4) Both PAG and HT inhibited the induction of lateral root growth. (5) RT-PCR analysis showed that SNP treatment could significantly induce the expression of Sl_OASTL / LCD in seedling roots. The above results indicate that NO may induce endogenous rootstocking of tomato seedlings by inducing the expression of Sl_OASTL / LCD.