Screening And Identification Of Rolled-leaf Rice Genetically Modified With Genes Of MYB Family

Rice leaf is the key photosynthetic organ.And leaf shape is an important part for breeding of plant type.Appropriate leaf rolling enhances erect-leaf habits and photosynthetic efficiency.Therefore,identifying more useful rolled-leaf genes is still an important goal for practical breeding in rice.The main content of this study is to transfer MYB-family genes into japonica rice cultivar Nipponzaki by agrobacterium transformation,and screen transgenic rice with stable leaf rolling traits.Cytology and molecular biology techniques are used to identify and investigate the agronomic traits of T₁ generation.Quantitative PCR is used to analyze the expression level of some genes associated with leaf rolling.The main research results are as follows:1.The over-expression vectors of 41 MYB-family genes endowed with transcription factors from maize are constructed by GATEWAY cloning technique.The results of PCR and sequencing show that the vectors are constructed successfully.2.Agrobacterium transformation method is used to transfer 41 MYB-family genes into calli of rice,and 652 plantlets are obtained by plant tissue culture technique,with an average of 16 for every gene.3.After screening of transgenic plants in T₀ and T₁ generations,it is found that the transgenic plant,No.AC270 shows a heritable and dominant trait of leaf rolling,and AC270 is loaded with MYBR96 gene by sequencing and BLAST.4.The number of bulliform cells of AC270 is less than that of wild plant by paraffin section and cell counting.5.Agronomic traits of AC270 are investigated,and the results show that the transpiration rate,stomatal conductance and intercellular CO₂ concentration are significantly higher than that of wild type.There is no significant difference in photosynthetic efficiency,1000-grain weight,tiller number,plant height and seed setting percentage.6.Quantitative analysis of the expression of 4 genes connected with leaf rollig show that the transcriptional mRNA of ROC5 gene increased in AC270,that of ACL1 decreased,and both of SRL1 and NRL1 have no significant differences,in contrast to wild type.These suggest that the transgenic lines of MYBR96 will provid the basis of material and technique for the genetic improvement of rice in the future.