| Maize is one of the most widely distributed crops and used for food,animal-feed production and industrial raw materials in the world.The production of maize plays a very important position in the national economy,however,it’s seriously threatened by different abiotic stresses,such as drought,salinity.Drought and salinity are the major threats to the world food supply.As we all know,ZF-HD TFs are a land plant-specific TFs,which plays regulatory roles in developmental processes and response to abiotic stresses.Several stress-tolerance relative genes from rice and Arabidopsis has been reports,but a little study has been functionally characterized in maize.In the study,a comprehensive survey and identification were performed in maize using bioinformatics methods,including gene structure,conserved motifs,genome duplication events,evolutionary relationship,and tissue-specific expression pattern.Furthermore,to explore stress-response mechanisms of ZF-HD genes in maize,the seeding’s leaves and root were treated with high salt,drought stress and ABA.The main results of this study are as follows:(1)A total numbers of 24 ZF-HD genes were recognized in the maize genome by Blast homologous search.These genes were unevenly distributed on chromosome 1 to 10,except chromosome 9.Six and two maize ZF-HD genes have occurred segmental and tandem duplication during gene expansion,which might play an important role in expansion of ZF-HD family.(2)To investigating gene structures of ZF-HD genes,we found most of them(21,87.5%)have no intron,this results also found in rice and Arabidopsis genes.To analyze the evolutionary history of the ZF-HD genes family,a phylogenetic analysis of ZF-HD proteins in maize,rice and Arabidopsis was performed by constructing a phylogenetic tree.As a result,all of ZF-HD genes were involved in six major groups based on gene structures.And each groups show highly similar in gene structures and the order of conserved motifs,which suggest this gene family is highly conserved.(3)The expression profiling of all of genes in12 different organs and developmental stages was examined in maize based on qTeller transcriptome database.As a result,most of maize ZF-HD genes are highly expressed in embryo,ear and tassel primordia and a half of members are highly expressed in silk,which implying that ZF-HD genes were participated in flower and seed development processes.(4)We investigated cis-elements in the promoter regions of 24 maize ZF-HD genes and found that 18 genes contain ABA responsive element(ABRE).In addition,expression patters in drought,salinity and ABA were identified by qRT-PCR.The results showed that most genes induce by drought or salt or ABA and there were two genes simultaneously in response to the three stresses.ZmZHD11 and ZmZHD12 significantly up-regulated under drought and salt stress,suggesting that its might be involved in signal transduction of ABA.(5)The candidate genes ZmZHD11 and ZmZHD12 have very similar amino acid lengths,compositions and steric structures.The protein sequences encoded by the candidate genes ZmZHD11 and ZmZHD12 were analyzed and found to have very similar protein properties,including amino acid lengths,compositions and steric structures.The overexpression vector was constructed to explore its mechanism of functions in abiotic stress. |
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