华中农业大学匡汉晖研究团队再探生菜结球的奥秘

放大字体缩小字体时间?022-08-11 10:06 来源:华中农业大?nbsp; 原文:
核心提示??日,华中农业大学匡汉晖教授研究团队以“Loss-of-function of SAWTOOTH 1 affects leaf dorsiventrality genes to promote leafy heads in lettuce”为题在The Plant Cell上发表了研究论文。该研究克隆了控制生菜结球的新基因LsSAW1,发现其可以下调近轴基因和上调远轴基因以促进生菜结球发育、/div>
  8?日,华中农业大学匡汉晖教授研究团队以Loss-of-function of SAWTOOTH 1 affects leaf dorsiventrality genes to promote leafy heads in lettuce为题在The Plant Cell上发表了研究论文。该研究 克隆了控刵a href='//www.sqrdapp.com/news/tag_1612.html' class='zdbq' title='生菜相关食品资讯' target='_blank'>生菜结球的新 基因LsSAW1,发现其可以下调近轴基因和上调远轴基因以促进生菜结球发育、/div>
  课题组前期已克隆了首个控制生菜结球的基因LsKN1(Lactuca sativa KNOTTED 1),其上调表达会促进叶球发育,但仅有LsKN1是不够的。在前期研究基础上,作者成功构建了一个结球与不结球表型分离的F5群体,且在该群体中,结球是隐性性状,结球个体近轴部分的细胞排列紊乱。利用BSA与RNA-seq分析,作者发现该群体中结球性状是由LHL1位点独立控制的,经过图位克隆与序列分析,作者发现LHL1位点中LG4_402589外显子上存在一个碱基的缺失,导致无法翻译出完整的蛋白,该基因与拟南芥SAW1同源,命名为LsSAW1。经过反向遗传学验证,作者证实了LHL1位点就是LsSAW1,其功能缺失(Lssaw1)对生菜结球的发育起到关键作用、/div>
  关于LsSAW1如何调控生菜结球发育,作者通过原位杂交发现LsSAW1主要在不结球植株叶片的近轴部表达,但在结球植株叶片的任何部位都检测不到它的表达,作者推测这种低表达可能由启动子的SNP引起,也可能是由外显子的突变引起。通过RNA-seq作者发现参与叶背腹极性有关,于是作者进一步分离了叶片近轴与远轴细胞进行RNA-seq,发现生长素信号与生长控制相关基因在在Lssaw1植株的DEGs中显著富集。进一步分析近轴与远轴部的差异基因发现,Lssaw1下调了近轴基因,上调了远轴基因,从而促进了生菜叶球的发育、/div>
  为了证实Lssaw1通过调节近轴与远轴基因促进叶球发育的假说,作者选择了一个近轴基因LsAS1进行进一步分析,发现LsAS1主要在不结球植株叶片的近轴部表达,而Lssaw1突变体中表达量显著下降。通过CHIP-seq,酵母单杂以及EMSA实验均证实了LsSAW1与LsAS1的启动子结合,Lssaw1下调LaAS1的表达,遗传实验也表明LaAS1下调会促进叶球发育,上调则会抑制叶球发育。作者对远轴面基因LsYAB1进行类似的实验发现,在Lssaw1突变体中LsYAB1的抑制作用减弱,有助于叶球发育、/div>
  作者希望通过酵母筛库来找到与LsSAW1一起调控叶片背腹性的蛋白,结果发现LsSAW1与之前研究的LsKN1存在互作,进一步研究发现,LsSAW1与LsKN1在叶球发育中的作用是相互拮抗的。例如LsSAW1可以直接与LsAS1启动子结合并上调其表达,同时减弱LsKN1对LsAS1的抑制作用,再次证实了Lssaw1可以直接和间接下调LsAS1的表达促进叶球发育。此外LsSAW1的同源基因LsSAW2在Lssaw1背景下过表达同样可以导致生菜不结球,但是一般情况下由于LsSAW2表达水平过低,导致其无法发挥冗余作用、/div>
  作者对488份生菜野生祖先进行重测序发现,竟然没有一份材料在Lssaw1中有一个碱基的缺失,但?1个现代品种中出现了这种突变,表明Lssaw1突变是人类驯化(好吃)的结果。体现出该突变对生菜育种以及叶球发育的重要性、/div>
  华中农业大学安光辉博士为论文第一作者,加州大学戴维斯分校Dean Lavelle与Richard W. Michelmore也参与该项研究,Elizabeth Georgian与康春颖教授对文章提出宝贵建议。本研究得到国家自然科学基金的资助、/div>
  英文摘要9/div>
  The mechanisms underlying leafy heads in vegetables are poorly understood. Here, we clo ned a quantitative trait locus (QTL co ntrolling leafy heads in lettuce (Lactuca sativa) The QTL encodes a trans cription factor, SAWTOOTH 1 (LsSAW1), which has a BEL1-like homeodomain and is a homolog of Arabidopsis thaliana. A 1-bp deletion in Lssaw1 co ntributes to the development of leafy heads. Laser-capture microdissection and RNA-sequencing showed that LsSAW1 regulates leaf dorsiventrality and loss-of-function of Lssaw1 downregulates the ex pression of many adaxial genes but upregulates abaxial genes. LsSAW1 binds to the promoter region of the adaxial gene ASYMMETRIC LEAVES 1 (LsAS1 to upregulate its ex pression. Overex pression of LsAS1 compromised the effects of Lssaw1 on heading. LsSAW1 also binds to the promoter region of the abaxial gene YABBY 1 (LsYAB1), but downregulates its ex pression. Overex pression of LsYAB1 led to bending leaves in LsSAW1 genotypes. LsSAW1 directly interacts with KNOTTED 1 (LsKN1), which is necessary for leafy heads in lettuce. RNA-seq data showed that LsSAW1 and LsKN1 exert antago nistic effects on the ex pression of thousands of genes. LsSAW1 compromises the ability of LsKN1 to repress LsAS1. Our results suggest that downregulation or loss-of-function of adaxial genes and upregulation of abaxial genes allow for the development of leafy heads.
  论文链接:https://academic.oup.com/plcell/advance-article/doi/10.1093/plcell/koac234/6653310
日期9a href="//www.sqrdapp.com/news/2022-08-11.html">2022-08-11
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