MeLAZY1c基因调控木薯株型的初步研究

Preliminary study on the regulation of cassava plant type by MeLAZY1c gene

IGT基因家族参与作物株型的调控,LAZY属于IGT的亚家族。以拟南芥6个LAZY成员氨基酸序列为“种子”在木薯基因组中进行比对,在木薯中共鉴定到8个LAZY基因,其中MeLAZY1c与调控分枝角度的AtLAZY1高度同源。基于此,本研究以MeLAZY1c为研究对象,利用qRT-PCR分析发现MeLAZY1c在茎中转录水平最高,GUS染色显示pMeLAZY1c在维管束中染色较深。在MeLAZY1c启动子中发现8个光响应/调节元件,随后发现黑暗能显著抑制其表达水平。同时对MeLAZY1c进行基因编辑,获得纯合编辑株系19个,炼苗移栽后观测表型,发现melazy1c突变体植株与SC8野生型相比,其主茎呈现匍匐生长,并且弯曲部位茎外皮细胞形态扭曲变形且大小不一致,近地侧1 mm处细胞数目约是远地侧细胞数量的1.5倍,表明MeLAZY1c在木薯直立/匍匐生长建成方面发挥着重要作用。

The IGT gene family is involved in the regulation of crop plant type,and LAZY belongs to the IGT subfamily.By comparing the amino acid sequences of six Arabidopsis LAZY members as‘seeds’in the cassava genome,a total of 8 LAZY genes were identified in cassava,among which MeLAZY1c is highly homologous to AtLAZY1,which regulates branching an-gles.Based on this,MeLAZY1c had the highest transcription level in the stem by qRT-PCR and pMeLAZY1c was deeply stained in the vascular bundle by GUS staining,using MeLAZY1c as the experimental materials in this study.Eight photorespon-sive/regulatory elements were found in the MeLAZY1c promoter,and we subsequently found that darkness significantly inhib-ited the relative expression level of MeLAZY1c.At the same time,gene editing of MeLAZY1c was performed and 19 homozygous edited lineages.The phenotype of MeLAZY1c mutants was observed after seedling transplantation,compared to the SC8 wild-type,the main stems of MeLAZY1c mutants had crawing growth,and the stem skin cells at the curved part were distorted and deformed with different sizes.The number of cells at 1 mm near the ground was about 1.5 times that of cells at the far ground.In conclusion,these results indicates that MeLAZY1c plays an important role in the establishment of upright/creeping growth of cassava.