Genome-wide Transcriptomic Analysis Reveals The Gene Regulatory Network That Controlled By TAW1 In Regulating Rice Inflorescence

TAW1（TAWAWA1）is a member of the ALOG（Arabidopsis LSH1 and Oryza G1）gene family.It regulates rice inflorescence development by maintaining the activity of inflorescence meristem and inhibiting the transformation of branch meristem to spikelet meristem.It is a specific regulator of rice meristem.In the gain-of-function mutant taw1-D,the increasing TAW1expression leads to the expression changes of several MADS box genes,which ultimately leads to an increase in the number of secondary branches.Current studies showed that the branch number of the loss-of-function mutant taw1 is reduced.However,its internal regulatory mechanism is still unclear.In order to explore the regulatory network of TAW1 in rice inflorescence development,we used the CRISPR/Cas9 gene editing system to generate a homozygous knockout line taw1^CRISPR with a reduction in number of secondary branches.Transcriptome sequencing was performed on the 2 cm young spikelet of the taw1^CRISPR strain as well as the control（non-KO）.A total of 2,819 genes were consider as differentially expressed genes（|log₂（Fold Change）|>1 and FDR<0.01）,920 of which were significantly up-regulated,while 1,899 were significantly down-regulated.Further analysis revealed that,unlike taw1-D,there was no significant change in the expression of MADS box gene in taw1^CRISPR.We speculated that the loss of TAW1 function does not lead to the expression change of the MADS box family and therefore the decrease in the number of secondary branches may not related to these MADS box genes.At the same time,there is also an up-regulation of DST（Drought and Salt Tolerance）,a gene that regulates the expression of cytokinin oxidative dehydrogenase in the transcriptome data.The experimental results show that TAW1 can bind to the DST promoter region to participate in the transcriptional regulation of DST and affect rice inflorescence development.This experiment deepens our understanding of the molecular mechanism of TAW1 regulating inflorescence development,and provides reliable evidence for further improving the regulation network of rice inflorescence development in the future.