Pollen Ultrastructure Observation And Starch Synthesis Pathway Analysis Of Maize Cytoplasmic Receptor-like Protein Kinase Mutants Zmstk1 And Zmstk2

In the laboratory,mutants of the pollen-specific genes Zmstk1 and Zmstk2 were obtained in the early stage.Through research on the mutants,the pollen germination rate decreased and starch accumulation decreased.In this study,wild-type Mc C,Zmstk1,Zmstk2,Zmstk1/Zmstk2 mutant anthers were subjected to tissue sectioning and ultra-thin sectioning under electron microscopy,real-time fluorescence quantification of starch synthesis-related genes in anthers,and determination of key enzymes for starch synthesis enzyme activity,to Find out why mutant starch has reduced starch accumulation.The results as follows:(1)Paraffin tissue sections and ultra-thin sections of wild-type Mc C,Zmstk1,Zmstk2,Zmstk1/Zmstk2 mutant anthers at various stages.The results showed that there was no significant difference between wild type and mutant in the early stage of anther development.In mature pollen,the Zmstk1,Zmstk2,Zmstk1/Zmstk2 mutant starch granules were reduced,and the inner and outer wall of the pollen were defective.(2)Real-time fluorescence quantification of key enzymes for starch synthesis in wild-type Mc C,Zmstk1,Zmstk2,Zmstk1/Zmstk2 mutant anthers at the tricellular pollen.The results showed that most of the starch synthesis-related enzyme genes were not significantly different in the wild-type and mutants,and the expression of amylose synthase GBSS? gene was significantly reduced in the Zmstk1,Zmstk2,and Zmstk1/Zmstk2 mutants..(3)Determination of the enzyme activities related to starch synthesis in the anthers of the tricellular pollen of wild-type Mc C,Zmstk1,Zmstk2,Zmstk1/Zmstk2 mutants,The results showed that the enzymatic activities of adenosine diphosphate glucose pyrophosphorylase(ADPGPase)and amylose synthase(GBSS)in pollen of Zmstk1,Zmstk2,and Zmstk1/Zmstk2 mutants were significantly lower than those of wild-type samples.To sum up,the Zmstk1,Zmstk2,Zmstk1/Zmstk2 mutant pollen reduced the number of starch granules,the expression level of the key enzyme gene for starch synthesis GBSS I is reduced,and the decreased enzyme activity of ADPGPase and GBSS I is the direct cause of the reduction of starch in pollen of mutants the reason.