Controlled free radical attack in the apoplast: a hypothesis for roles of O, N and S species in regulatory and polysaccharide cleavage events during rapid abscission by Azolla.
Controlled free radical attack in the apoplast: a hypothesis for roles of O, N and S species in regulatory and polysaccharide cleavage events during rapid abscission by Azolla.
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DOI：
10.1016/j.plantsci.2013.12.008
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发表时间：
2014-03
期刊：
影响因子：
5.2
通讯作者：
Yamasaki, Hideo
中科院分区：
文献类型：
--
作者：
Cohen, Michael F.;Gurung, Sushma;Fukuto, Jon M.;Yamasaki, Hideo
植物器官的脱落是植物发育和逆境反应的关键步骤。细胞壁（CW）松散的剥离区可以发生通过组合链断裂的质外体多糖和张力释放的纤维素微纤维。两个明显的调节diperission裂解事件是适合于研究在小水蕨类植物的满江红属;一个是快速diperission诱导的环境刺激，如热或化学品，另一个是乙烯诱导的过程发生更缓慢，通过水解酶的作用。虽然自由基被认为参与了快速根脱落的诱导，但其机制尚不完全清楚。质外体含有过氧化物酶、金属结合蛋白和酚类化合物，它们可能从H2 O2产生自由基以裂解CW和中间层中的多糖。各种巯基反应剂的作用暗示了具有可接近的半胱氨酸巯基的质外体过氧化物酶在快速分解中的作用。快速分解的Ca ~（2+）依赖性可能反映了Ca ~（2+）赋予过氧化物酶结构和与果胶结合的稳定性。为了促进进一步的研究，我们提出了一个假设的模型，小信号分子H2 O2和NO及其衍生物的调节，通过修改假定的蛋白质硫醇，自由基攻击的质外体多糖。
Shedding of organs by abscission is a key terminal step in plant development and stress responses. Cell wall (CW) loosening at the abscission zone can occur through a combination chain breakage of apoplastic polysaccharides and tension release of cellulose microfibrils. Two distinctly regulated abscission cleavage events are amenable to study in small water ferns of the genus Azolla; one is a rapid abscission induced by environmental stimuli such as heat or chemicals, and the other is an ethylene-induced process occurring more slowly through the action of hydrolytic enzymes. Although free radicals are suggested to be involved in the induction of rapid root abscission, its mechanism is not fully understood. The apoplast contains peroxidases, metal-binding proteins and phenolic compounds that potentially generate free radicals from H2O2 to cleave polysaccharides in the CW and middle lamella. Effects of various thiol-reactive agents implicate the action of apoplastic peroxidases having accessible cysteine thiols in rapid abscission. The Ca2+ dependency of rapid abscission may reflect the stabilization Ca2+ confers to peroxidase structure and binding to pectin. To spur further investigation, we present a hypothetical model for small signaling molecules H2O2 and NO and their derivatives in regulating, via modification of putative protein thiols, free radical attack of apoplastic polysaccharides.
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影响因子：
3.9
作者：
Castro, L;Eiserich, JP;Freeman, BA
通讯作者：
Freeman, BA
DOI：
10.1111/j.1365-3040.1978.tb00765.x
发表时间：
1978-01-01
期刊：
Plant, Cell and Environment
影响因子：
--
作者：
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通讯作者：
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作者：
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影响因子：
4.3
作者：
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通讯作者：
Krieger-Liszkay, Anja
影响因子：
3
作者：
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通讯作者：
Vaughn, Kevin C.