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提高植物生物量和/或原料质量以高效转化木质纤维素一直是生物燃料生产模式植物柳枝稷(Panicum virgatum L.)转基因的主要研究重点。 在这里，我们证明了miR396(OE-miR396)的过表达主要是通过降低G-木质素单体含量而导致株高和木质素含量降低。我们在柳枝稷中鉴定了19个pvGRF，其中13个被miR396切割。以MiR396为靶标的PvGRF1、PvGRF9和PvGRF3在茎中的表达显著增加。通过分别过表达rPvGRF1、3和9(其中同义突变取消了miR396个目的位点)和通过PvGRF1/3/9-SRDX过表达抑制PvGRF1/3/9活性，我们证实了PvGRF1和PvGRF9在提高株高和G-木质素含量方面起到了正向调控作用。 PvGRF9的过表达足以弥补OE-miR396植株的缺陷表型。 MiR396-PvGRF9通过干扰GA和生长素的生物合成，以及信号转导和细胞壁木质素、葡萄糖和木聚糖的生物合成途径，部分调控了这些性状。此外，通过酶解分析，我们发现rPvGRF9的过表达显著提高了单株产糖量。我们的研究结果表明，PvGRF9可以作为改良植物生物量和原料品质的候选分子工具。 Improving plant biomass yield and/or feedstock quality for highly efficient lignocellulose conversion has been the main research focus in genetic modification of switchgrass (Panicum virgatum L.), a dedicated model plant for biofuel production. Here, we proved that overexpression of miR396 (OE‐miR396) leads to reduced plant height and lignin content mainly by reducing G‐lignin monomer content. We identified nineteen PvGRFs in switchgrass and proved thirteen of them were cleaved by miR396. MiR396‐targeted PvGRF1, PvGRF9 and PvGRF3 showed significantly higher expression in stem. By separately overexpressing rPvGRF1, 3 and 9, in which synonymous mutations abolished the miR396 target sites, and suppression of PvGRF1/3/9 activity via PvGRF1/3/9‐SRDX overexpression in switchgrass, we confirmed PvGRF1 and PvGRF9 played positive roles in improving plant height and G‐lignin content. Overexpression of PvGRF9 was sufficient to complement the defective phenotype of OE‐miR396 plants. MiR396‐PvGRF9 modulates these traits partly by interfering GA and auxin biosynthesis and signalling transduction and cell wall lignin, glucose and xylan biosynthesis pathways. Moreover, by enzymatic hydrolysis analyses, we found that overexpression of rPvGRF9 significantly enhanced per plant sugar yield. Our results suggest that PvGRF9 can be utilized as a candidate molecular tool in modifying plant biomass yield and feedstock quality.Improving plant biomass yield and/or feedstock quality for highly efficient lignocellulose conversion has been the main research focus in genetic modification of switchgrass (Panicum virgatum L.), a dedicated model plant for biofuel production. Here, we proved that overexpression of miR396 (OE‐miR396) leads to reduced plant height and lignin content mainly by reducing G‐lignin monomer content. We identified nineteen PvGRFs in switchgrass and proved thirteen of them were cleaved by miR396. MiR396‐targeted PvGRF1, PvGRF9 and PvGRF3 showed significantly higher expression in stem. By separately overexpressing rPvGRF1, 3 and 9, in which synonymous mutations abolished the miR396 target sites, and suppression of PvGRF1/3/9 activity via PvGRF1/3/9‐SRDX overexpression in switchgrass, we confirmed PvGRF1 and PvGRF9 played positive roles in improving plant height and G‐lignin content. Overexpression of PvGRF9 was sufficient to complement the defective phenotype of OE‐miR396 plants. MiR396‐PvGRF9 modulates these traits partly by interfering GA and auxin biosynthesis and signalling transduction and cell wall lignin, glucose and xylan biosynthesis pathways. Moreover, by enzymatic hydrolysis analyses, we found that overexpression of rPvGRF9 significantly enhanced per plant sugar yield. Our results suggest that PvGRF9 can be utilized as a candidate molecular tool in modifying plant biomass yield and feedstock quality. MiR396‐GRF module associates with switchgrass biomass yield and feedstock quality10.1111/pbi.13567  文章来源原创；转载请注明来源。 温馨提示： 为方便PaperRSS粉丝们科研、就业等话题交流。我们根据10多个专业方向（植物、医学、药学、人工智能、化学、物理、财经管理、体育等），特建立了30个国内外博士交流群。群成员来源欧美、日韩、新加坡、清华北大、中科院等全球名校。 |
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