Isolation And Functional Studies Of The Related Transcription Factors In Rice Seed Development

Rice is an important food crop, and it has been as an importantmonocotyledonous model species for molecular genetics studies. The seeds of riceare the primary food sources of the world. Thus our study focused on thetranscription regulation during rice seed development.In the first part, an efficient yeast-based system was developed for the isolation ofplant cDNAs encoding transcription factors (TFs) and proteins with transcriptionactivation functions (co-activators) in rice embryo development. The system is basedon the trans-activation domain screening and ?-galactosidase (lacZ) reporter genesystem; TFs during rice embryo development are isolated through this system.Approximately 200 confirmed positive colonies were obtained from screening 106yeast colonies, including 75 independent cDNAs: 20 of which encoded plant TFs orco-activators belonging to different gene families; Peptides encoded by 13 of theisolated cDNAs are classified as potential TFs or co-activators because of thepresence of conserved TF-like domains. Expression pattern of selected TF-encodinggenes was analyzed via RT-PCR. This work provides informative hints for furtherstudy of the regulatory mechanism of rice seed development, and illustrates anidentification strategy that will be of practical value for the isolation of TFs andco-activators associated with specific plant developmental processes. Then westudied the OsGRF4 and OsGRF5 gene encoding the transcription activators, whichwere isolated through our yeast system. We found that these two genes are highlyexpressed during the flower and seed development. And the expression of OsGRF5 isslightly induced treating with Gibberellin. OsGRF5 protein can localize in the cellnucleus. The phenotype of the OsGRF5 anti-sense transgenic rice implied this genemay be essential for rice anther development.In the second part, a collection of rice mutated lines harbouring T-DNAinsertion has been generated, together with the set up of the efficient technology ofhigh-throughput thermal asymmetric interlaced (TAIL)-PCR to recover the flankingsequence of the T-DNA left borders. Nearly 43% mutants are linked with the FST(flanking sequence tag). All the FST are analyzed in the bioinformatics pipelineagainst the TIGR Rice Pseudomolecules (virtual contigs). Plants showing mutationrelated with flower and seed development are screened and studied. All theseinformation has been settled into the mutant database.(http://www.plantsignal.cn/ship).