Producing Transgenic Lines With Large Kernel Through Overexpressing ZmANT Gene In Maize(Zea Mays L.)

Maize(Zea mays L.)is one of important economic crops and food crops,and yield of maize is the foundation of the agricultural development.Because the yield of maize is restricted by planting area and density,the kernel size and weight are the most important elements.Therefore,cloning the key gene regulating maize kernel characters and discovering their biological functions have important theoretical and practical significance.Here,we identified ZmANT gene in maize,and found that it was the homologous gene of AINTEGUMENTA(ANT)in Arabidopsis.We then produced new transgenic lines in maize with large kernel through overexpressing ZmANT gene.The main results are as follows:Cloning and homologous analysis of ZmANT gene.In Arabidopsis,the ANT gene plays a central role in increasing size of plant organs and seeds.In this study,we identified and cloned a homologous gene of Arabidopsis ANT in maize,and named it as ZmANT.The overexpression of ZmANT rescued the phenotype of small seeds in the ant mutants.We constructed 35S::ZmANT vector,and transferred it into the wild type(Col)and ant mutants of Arabidopsis.The results showed that the overexpression of ZmANT gene significantly increased seed size and weight in the wild type of Arabidopsis,and completely rescued the small and light seeds of the ant mutants.Therefore,ZmANT gene has homologous function with ANT in the regulation of seed size.The expression pattern of ZmANT gene.Through analyzing the expression of ZmANT by qRT-PCR,we found that ZmANT gene was widely expressed in various tissues of maize.Among them,the expression levels in the seeds were the highest.The results of in situ hybridization showed that ZmANT gene was expressed in embryos,endosperm and pericarp,the expression signals in embryos were the highest.This indicated that ZmANT gene may play an important role in the regulation of the kernels in maize.Obtaining and identification of the transgenic plants in maize,with overexpression of ZmANT.We constructed the pUbi::ZmANT vector and transferred it into the KN5585 inbred line.Until now,two generation of transgenic lines have been obtained.Among them,12 positive transgenic plants were identified in T0 generation.After they were planted in the field,49 positive transgenic plants were identified in T1 generation.Phenotype analysis of ZmANT transgenic plants in maize.Because the various stress effects during gene transformation,transgenic plants had abnormal kernel phenotypes in T0 generation.However,some T0 positive transgenic plants still had increased kernel weight.We further found that the expression levels of ZmANT gene were significantly increased in the T0 positive transgenic plants,compared to the wild type.In T1 positive transgenic lines,the kernel size and weight were significantly increased.The plant height of several positive lines are also much increased than the wild type.The above result indicate that ZmANT plays an important role in regulating kernel size and weight of maize.In summary,overexpressing ZmANT gene in maize results in increased kernel size and weight,as well as the plant height.It is useful for producing transgenic lines with good agronomic traits and increased yield in maize.