ABSTRACT Root architecture depends on the development of the main root and also on the number and density of lateral roots. Most molecular knowledge about the development of lateral roots was acquired studying primary roots, and it was implied that high order roots follow the same pattern. Recently, we informed that AtHB23 is differentially regulated in primary and secondary roots. Here we show that LBD16, a target of AtHB23, also is differentially regulated; it is expressed in the tip of secondary and tertiary roots but not in primary ones. Moreover, the key hormone auxin exhibits a different distribution pattern in secondary and tertiary roots, according to the reporter DR5. Finally, we show that in Col 0 and Ler ecotypes development of secondary and tertiary roots exhibits significant variations. Altogether, we can conclude that different genetic programs govern secondary and tertiary roots development and such processes are dependent on the Arabidopsis genotype.

中文翻译：

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主根和次生根的侧根发育不同，取决于生态型

摘要 根系结构取决于主根的发育以及侧根的数量和密度。大多数关于侧根发育的分子知识是通过研究初级根获得的，这意味着高级根遵循相同的模式。最近，我们了解到 AtHB23 在初级和次级根中受到差异调节。在这里，我们表明 AtHB23 的目标 LBD16 也受到差异调节；它在二级和三级根的尖端表达，但不在初级根中表达。此外，根据记者 DR5 的说法，关键激素生长素在二级和三级根中表现出不同的分布模式。最后，我们表明在 Col 0 和 Ler 生态型中，二级和三级根的发育表现出显着差异。共，