ABSTRACT Leaf development is a complex process and factors such as size, shape, curvature, compounding, and texture determine the final leaf morphology. MicroRNA160 is one of the crucial players that has been shown to regulate lamina formation and compounding in tomato. In this study, we show that miR160 also regulates leaf curvature in potato. miR160 targets a group of Auxin Response Factors – StARF10, StARF16, and StARF17 – that are proposed to function majorly as repressors of auxin signaling. We observed that overexpression of miR160 (miR160-OE) results in decrease in the levels of these ARFs along with hypersensitivity to exogenous auxin treatment, whereas knockdown of miR160 (miR160-KD) causes increased ARF levels and auxin hyposensitivity. The leaves of miR160-OE plants have a high positive curvature, but of miR160-KD plants are flattened compared to wildtype. A prolonged activation of cell cycle – as indicated by increased levels of StCYCLIND3;2 – in the center region of miR160-OE leaves appears to have caused this positive curvature. However, a comparable StTCP4 activity at both center and margin regions of miR160-KD leaves could be the cause for its flattened leaf phenotype. In summary, we show that miR160 plays an important role in regulating leaf curvature in potato plants.

中文翻译：

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MicroRNA160 调节马铃薯叶片曲率 (Solanum tuberosum L. cv. Désirée)

摘要 叶片发育是一个复杂的过程，大小、形状、曲率、复合和质地等因素决定了最终的叶片形态。MicroRNA160 是已被证明可调节番茄叶片形成和复合的关键参与者之一。在这项研究中，我们表明 miR160 还调节马铃薯的叶片曲率。miR160 靶向一组生长素反应因子——StARF10、StARF16 和 StARF17——它们被认为主要作为生长素信号传导的阻遏物。我们观察到 miR160 (miR160-OE) 的过表达导致这些 ARF 水平降低以及对外源生长素处理的超敏反应，而 miR160 (miR160-KD) 的敲低导致 ARF 水平增加和生长素低敏感性。miR160-OE 植物的叶子具有较高的正曲率，但 miR160-KD 植物与野生型相比变平。miR160-OE 叶中心区域的细胞周期激活时间延长——如 StCYCLIND3;2 水平增加所表明的那样，似乎导致了这种正曲率。然而，在 miR160-KD 叶的中心和边缘区域具有相当的 StTCP4 活性可能是其扁平叶表型的原因。总之，我们表明 miR160 在调节马铃薯植物的叶片曲率中起重要作用。