Ethylene-auxin interactions regulate lateral root initiation and emergence in Arabidopsis thaliana
Ethylene-auxin interactions regulate lateral root initiation and emergence in Arabidopsis thaliana
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DOI：
10.1111/j.1365-313x.2008.03528.x
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发表时间：
2008-07-01
期刊：
影响因子：
7.2
通讯作者：
Dubrovsky, Joseph G.
中科院分区：
文献类型：
--
作者：
Ivanchenko, Maria G.;Muday, Gloria K.;Dubrovsky, Joseph G.
植物根系对内源和环境信号的响应表现出相当大的可塑性。生长素刺激伸长的初生根中的中柱细胞进入新的器官发生，导致新的侧根分生组织的建立。生长素和乙烯在根伸长过程中的串扰已经被证明，但这些激素在根分枝过程中的相互作用还没有得到很好的描述。我们发现，由于低浓度的乙烯前体1-氨基环丙烷-1-羧酸(ACC)的应用，促进了乙烯合成，促进了侧根原基的启动。用较高剂量的ACC处理会强烈抑制周细胞启动新的侧根原基的能力，但会促进现有的侧根原基的出现：这种行为也可以在To1突变中看到。这些效应与中柱细胞长度的缩短和侧根原基细胞宽度的增加有关。当生长素与ACC同时应用时，ACC不能阻止在ACC暴露之前形成的根组织中生长素对侧根形成的刺激。然而，在转移到ACC后形成的根组织中，生长素并没有挽救乙烯对原基起始的抑制，而是将其增加了几倍。阻断生长素反应的突变slr1和arf7 arf19使侧根原基的启动对低乙烯水平的促进作用不敏感，而抑制乙烯刺激的生长素生物合成的突变wei2和wei7降低了较高乙烯水平的抑制效应，这与乙烯通过与生长素相互作用调节根分支一致。
Plant root systems display considerable plasticity in response to endogenous and environmental signals. Auxin stimulates pericycle cells within elongating primary roots to enter de novo organogenesis, leading to the establishment of new lateral root meristems. Crosstalk between auxin and ethylene in root elongation has been demonstrated, but interactions between these hormones in root branching are not well characterized. We find that enhanced ethylene synthesis, resulting from the application of low concentrations of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), promotes the initiation of lateral root primordia. Treatment with higher doses of ACC strongly inhibits the ability of pericycle cells to initiate new lateral root primordia, but promotes the emergence of existing lateral root primordia: behaviour that is also seen in the eto1 mutation. These effects are correlated with decreased pericycle cell length and increased lateral root primordia cell width. When auxin is applied simultaneously with ACC, ACC is unable to prevent the auxin stimulation of lateral root formation in the root tissues formed prior to ACC exposure. However, in root tissues formed after transfer to ACC, in which elongation is reduced, auxin does not rescue the ethylene inhibition of primordia initiation, but instead increases it by several fold. Mutations that block auxin responses, slr1 and arf7 arf19, render initiation of lateral root primordia insensitive to the promoting effect of low ethylene levels, and mutations that inhibit ethylene-stimulated auxin biosynthesis, wei2 and wei7, reduce the inhibitory effect of higher ethylene levels, consistent with ethylene regulating root branching through interactions with auxin.