丛枝菌根真菌对柳枝稷苗期生长作用机制的研究

柳枝稷(Panicum virgatum L.)存在苗期生长缓慢的现象,而菌根真菌与植物共生可以促进植物生长。为了探究菌根真菌对柳枝稷苗期生长的影响,我们以来自于柳枝稷低地型品种Alamo的2个品系Ma和Mg为材料,诱导丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)与柳枝稷共生,研究丛枝菌根真菌对柳枝稷苗期生长的影响及其分子机制。结果表明:丛枝菌根真菌可以侵入苗期柳枝稷根的内部形成共生菌根,并显著增加柳枝稷苗期的叶绿素含量、株高、叶片数和生物量。寄生植物瓜列当(Orobanche aegyptiaca)种子萌发和独脚金内酯(Strigolactones,SLs)合成标记基因检测实验表明,丛枝菌根真菌与柳枝稷共生可以抑制柳枝稷根系合成独脚金内酯,进而解除独脚金内酯对柳枝稷分蘖的抑制作用,促进柳枝稷苗期的生长。

Mechanistic Insights into the Arbuscular Mycorrhizal Fungi on the Growth of Switchgrass during Seedling Stage

Switchgrass (Panicum virgatum L.) grows slowly at the seedling stage, while it was known that mycorrhizal symbiosis has positive effects on plant growth.To reveal the impact of mycorrhizal symbiosis on the seedling growth of switchgrass, two cultivars of switchgrass, Ma and Mg, were inoculated with Arbuscular mycorrhizal fungi (AMF).The results showed that AMF successfully infected the roots of switchgrass and formed arbuscular mycorrhizae, which improved the content of chlorophyll, the growth of roots and leaves and biomass of the infected switehgrass.The extracts from root of AMF-infected switchgrass dramatically reduced the germination rate of Orobanche aegyptiaca seeds.In addition, the expression of genes D10 and D27, the main genes in the synthesis pathway of strigolactones, was decreased obviously in switchgrass with AMF.Our results suggested that switchgrass inoculated with AMF at seedling stage may restrain the biosynthesis of strigolactones, a newly identified plant hormone with inhibitory effects on plant branching, and promote the growth of switchgrass at seedling stage.