Effects of glucose and ethylene on root hair initiation and elongation in lettuce (Lactuca sativa L.) seedlings
Effects of glucose and ethylene on root hair initiation and elongation in lettuce (Lactuca sativa L.) seedlings
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DOI：
10.1007/s10265-017-1003-8
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发表时间：
2018-05-01
影响因子：
2.8
通讯作者：
Takahashi, Hidenori
中科院分区：
文献类型：
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作者：
Harigaya, Wakana;Takahashi, Hidenori
转移到酸性介质（pH 4.0）后，生菜幼苗会形成根毛。这个过程需要根表皮细胞和植物激素乙烯中的皮质微管（CMT）随机化。我们研究了乙烯和葡萄糖（植物中的一种新信号分子）在生菜根发育中的相互作用，重点是根毛的形成。使用黑暗生长的幼苗来排除光合作用产生的葡萄糖的影响。在黑暗中，即使转移到酸性介质（pH 4.0）后，也不会发生根毛形成和之前的 CMT 随机化。向培养基中添加 1-氨基环丙烷-1-羧酸 (ACC) 可挽救诱导，而添加葡萄糖则不能。虽然当葡萄糖与 ACC 一起施用时会发生 CMT 随机化，但与 ACC 处理的幼苗相比，它在一定程度上受到抑制。这并不是由于随机化速度的降低，而是由于最大随机化程度的降低。尽管葡萄糖对 ACC 诱导的 CMT 随机化有负面影响，但当同时添加葡萄糖时，ACC 诱导的根毛的密度和长度增加。 ACC处理幼苗的毛细胞长度与联合处理幼苗的毛细胞长度相当，表明葡萄糖引起的毛密度增加是由于根毛数量增加所致。此外，定量 RT-PCR 显示葡萄糖抑制乙烯信号传导。这些结果表明，葡萄糖分别对根毛形成的早期和晚期阶段具有负面和正面影响，并且葡萄糖对根毛的起始和伸长的促进可能以不依赖于乙烯的方式介导。
Root hair formation occurs in lettuce seedlings after transfer to an acidic medium (pH 4.0). This process requires cortical microtubule (CMT) randomization in root epidermal cells and the plant hormone ethylene. We investigated the interaction between ethylene and glucose, a new signaling molecule in plants, in lettuce root development, with an emphasis on root hair formation. Dark-grown seedlings were used to exclude the effect of photosynthetically produced glucose. In the dark, neither root hair formation nor the CMT randomization preceding it occurred, even after transfer to the acidic medium (pH 4.0). Adding 1-aminocyclopropane-1-carboxylic-acid (ACC) to the medium rescued the induction, while adding glucose did not. Although CMT randomization occurred when glucose was applied together with ACC, it was somewhat suppressed compared to that in ACC-treated seedlings. This was not due to a decrease in the speed of randomization, but due to lowering of the maximum degree of randomization. Despite the negative effect of glucose on ACC-induced CMT randomization, the density and length of ACC-induced root hairs increased when glucose was also added. The hair-cell length of the ACC-treated seedlings was comparable to that in the combined-treatment seedlings, indicating that the increase in hair density caused by glucose results from an increase in the root hair number. Furthermore, quantitative RT-PCR revealed that glucose suppressed ethylene signaling. These results suggest that glucose has a negative and positive effect on the earlier and later stages of root hair formation, respectively, and that the promotion of the initiation and elongation of root hairs by glucose may be mediated in an ethylene-independent manner.