Development|保守的LBL1-ta-siRNA和miR165/166-RLD1/2模块调控玉米根系发育

单子叶玉米的根系构型和解剖结构与双子叶模式拟南芥有很大的不同。对非编码RNA(NcRNA)在玉米根系发育中的分子作用知之甚少。

在这里，我们讨论了LEAFBLADELESS1(LBL1)在玉米根系发育中的作用，LBL1是玉米反式作用短干扰RNA(ta-siRNA)的一个组成部分。我们报道了lbl1-rgd1突变体的根生长、解剖形态、侧根数量、单子叶特有的冠根(CRS)和种子根(SRS)受到显著影响，该突变体的ta-siRNA的产生存在缺陷，其中包括针对玉米生长素应答因子3(ARF3)的tasiR-ARF。生长素生物合成和转运蛋白基因的差异表达改变了生长素的积累和分布，造成了生长素信号的不平衡。

MicroRNA165/166(miR165/166)及其靶标ROLLED1/2(RLD1/2)的表达改变导致了lbl1-rgd1根的生长和维管构型的改变，这在rld1-O半显性突变体的根表型改变中表现得尤为明显。

因此，LBL1/ta-siRNA模块在与miR165/166-RLD1/2模块的串扰中，可能通过影响生长素的分配和信号转导来调节根的发育。我们进一步证明了ZmLBL1及其拟南芥同源基因AtSGS3蛋白在功能上是保守的。

Root system architecture and anatomy of monocotyledonous maize is significantly different from dicotyledonous model Arabidopsis. The molecular role of non-coding RNA (ncRNA) is poorly understood in maize root development. Here we address the role of LEAFBLADELESS1 (LBL1), a component of maize trans-acting short-interfering RNA (ta-siRNA), in maize root development. We report that the root growth, anatomical patterning, number of lateral roots (LRs) and monocot-specific crown roots (CRs) and seminal roots (SRs) are significantly affected in lbl1-rgd1 mutant, which is defective in production of ta-siRNA, including tasiR-ARF that targets AUXIN RESPONSE FACTOR3 (ARF3) in maize. Altered accumulation and distribution of auxin, due to differential expression of auxin biosynthesis and transporter genes, created an imbalance in auxin signaling. Altered expression of microRNA165/166 (miR165/166) and its targets ROLLED1/2 (RLD1/2) contributed to the changes in lbl1-rgd1 root growth and vascular patterning, as was evident by altered root phenotype of Rld1-O semi-dominant mutant. Thus, LBL1/ta-siRNA module regulates root development, possibly by affecting auxin distribution and signaling, in crosstalk with miR165/166-RLD1/2 module. We further showed that ZmLBL1 and its Arabidopsis homolog AtSGS3 proteins are functionally conserved.

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