1分子植物综述|水稻功能基因组学研究：过去的十年和未来

2新植物学家|一种新的反义长编码RNA，TWISTED LEAF，通过调节其相关的水稻R2R3-MYB基因来维持叶片扁平化

   天然反义长链非编码RNA（lncRNAs）在许多生物体中广泛存在。然而，它们的生物功能在很大程度上还是未知的，特别是在植物中我们报告了从水稻（Oryza sativa）中的R2R3 MYB转录因子基因座OsMYB60的相反链转录的内源性lncRNA（TWISTED LEAF（TL））的鉴定和表征。发现TL和OsMYB60在许多不同的组织中共表达，TL的表达水平高于OsMYB60。通过RNA干扰（RNAi）下调TL和OsMYB60的过表达导致转基因水稻叶片扭曲。在TL-RNAi转基因植物中OsMYB60的表达水平显着增加。这表明TL可能对OsMYB60在叶片形态发育中起顺式调控作用。我们还确定反义转录通过介导染色质修饰来抑制有义基因的表达。我们进一步发现C2H2转录因子OsZFP7是一个OsMYB60结合伴侣，参与叶片发育。综上所述，这些发现揭示了顺式天然反义lncRNA在维持水稻叶片扁平化中起关键作用。我们的研究揭示了lncRNA在植物叶发育中的调控机制。

Summary

   Natural antisense long noncoding RNAs (lncRNAs) are widespread in many organisms. However, their biological functions remain largely unknown, particularly in plants.

   We report the identification and characterization of an endogenous lncRNA, TWISTED LEAF (TL), which is transcribed from the opposite strand of the R2R3 MYB transcription factor gene locus, OsMYB60, in rice (Oryza sativa). TL and OsMYB60 were found to be coexpressed in many different tissues, and the expression level of TL was higher than that of OsMYB60.

   Downregulation of TL by RNA interference (RNAi) and overexpression of OsMYB60 resulted in twisted leaf blades in transgenic rice. The expression level of OsMYB60 was significantly increased in TL-RNAi transgenic plants. This suggests that TL may play a cis-regulatory role on OsMYB60 in leaf morphological development. We also determined that the antisense transcription suppressed the sense gene expression by mediating chromatin modifications. We further discovered that a C2H2 transcription factor, OsZFP7, is an OsMYB60 binding partner and involved in leaf development.

   Taken together, these findings reveal that the cis-natural antisense lncRNA plays a critical role in maintaining leaf blade flattening in rice. Our study uncovers a regulatory mechanism of lncRNA in plant leaf development.

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   尽管种子灌浆机制对作物产量具有相关性，但我们仍然只能对用糖提供颖果的运输过程有一个基本的了解。我们假设SWEET蔗糖转运蛋白可能在水稻颖果营养物质输入途径中发挥重要作用。我们使用了mRNA定量，组织化学分析，翻译启动子 - 报道基因融合以及通过基因组编辑创建的敲除突变体的分析来评估SWEET转运蛋白对种子填充的贡献。在水稻颖果中，SWEET11和15具有最高的mRNA水平，蛋白质定位于四个关键位点：珠心早期的所有区域;靠近背静脉的珠心投影;围绕胚乳的珠心表皮;和糊粉。 ossweet11; 15双重淘汰线积累在果皮淀粉，而caryopses不包含功能胚乳。 SWEET11和15共同显示了在珠心投影中具有蔗糖外排功能的籽粒灌浆所必需的标记以及在珠心表皮/糊粉界面上的转移作用的所有特征，描述了用于胚珠种子充填的两个主要步骤，关于大米和大麦观察到的这两种潜在进口路线的相对流行情况。

Summary

   Despite the relevance of seed-filling mechanisms for crop yield, we still have only a rudimentary understanding of the transport processes that supply the caryopsis with sugars. We hypothesized that SWEET sucrose transporters may play important roles in nutrient import pathways in the rice caryopsis.

We used a combination of mRNA quantification, histochemical analyses, translational promoter–reporter fusions and analysis of knockout mutants created by genomic editing to evaluate the contribution of SWEET transporters to seed filling.

In rice caryopses, SWEET11 and 15 had the highest mRNA levels and proteins localized to four key sites: all regions of the nucellus at early stages; the nucellar projection close to the dorsal vein; the nucellar epidermis that surrounds the endosperm; and the aleurone. ossweet11;15 double knockout lines accumulated starch in the pericarp, whereas caryopses did not contain a functional endosperm.

Jointly, SWEET11 and 15 show all the hallmarks of being necessary for seed filling with sucrose efflux functions at the nucellar projection and a role in transfer across the nucellar epidermis/aleurone interface, delineating two major steps for apoplasmic seed filling, observations that are discussed in relation to observations made in rice and barley regarding the relative prevalence of these two potential import routes.