Studies On BeCesAs Gene Expression Patterns Of Bambusa Emeiensis And Their Genetic Transformation In Populus Tomentosa

Bambusa emeiensis is one of the most common bamboo species in Southwest China,in which the content of cellulose is high,So it is good material for papermaking.CesA is the key gene of cellulose synthesis,which is not only related to the content of cellulose,but also related to plant growth and development.However,there is no report about the efects of the BeCesA gene on the growth and cellulose content of Bambusa emeiensis.In view of this,2 BeCesAs genes that regulate the biosynthesis of cellulose were cloned from bamboo shoots in this study.To provide a theoretical and practical basis for improving the quality of bamboo by transgenic engineering,their bioinformatic analysis,expression patters and transformation were carried out.The main results are as follows:1.Based on the full length sequences of four BeCesAs gene?BeCesA1,BeCesA2,BeCesA7 and BeCesA8?in the laboratory,the c DNA sequence of two new BeCesAs gene were successfully cloned from Bambusa emeiensis.These genes had been named BeCesA3 and BeCesA4,respectively.The full-length cDNA sequence of Be CesA3 and 4 were 3282 bp and 2949 bp,which encoded 1093 and 982 amino acids,respectively.Their registration numbers in GenBank are KX424591 and KX424592,respectively.2.The bioinformatics analysis showed that BeCesA1,BeCes A2,BeCesA3,BeCesA4,BeCesA7 and BeCesA8 had the closest genetic relationship with OsCesA1,BoCesA3,OsCesA3,OsCesA4,Os CesA7 and BoCesA4,respectively.Furthermore,the proteins possess four motifs?D,DxD,D,Q / Rxx RW?that have been identified as being conserved in CesAs and all processive glucosyl transferase,a sequence highly conserved in the plant CesAs called P-CR,two variable regions called VR1 and VR2,a region of acidic amino acid enrichment called ARR.3.The results of tissue expression pattern analysis showed that BeCesA1,3 expression was higher in unexpanded leaves and 30 cm shoots,but lower in the expanded leaves and 100 cm shoots,while the expression pattern of BeCesA4,7 is opposite to BeCesA1,3.The relative expression level of BeCesA1,3,4,7 gene in 30 cm,50cm and 170 cm shoots was further measured.The relative expression level of BeCesA1,3 gene was gradually decreased with the increase of the height of bamboo shoots,and the expression trend of BeCesA4,7 gene are completely opposite to BeCesA1,3 genes.4.The seedling plants of Bambusa emeiensis were treated with GA₃ and DMZ.The results showed that the BeCesA3 and 4 were conspicuously induced both by GA₃ and DMZ in the unfolded leaves,while GA₃ could promote the expression of BeCesA3 and inhibit the expression of BeCesA4 in the expanded leaves.GA₃ promoted internode elongation of lateral branch by promoting cell elongation from Bambusa emeiensis,while DMZ promotes internode elongation of lateral branch by promoting cell division.However,the effects of two reagents on the cellulose content is different,the cellulose content increased in culm but it decreased in expanded leaf treated by GA₃ treatment,while the cellulose content decreased in culm and leaf treated by DMZ treatment.Further study found that there are significant positive correlation between the expression of NAC29/31,MYB61 and BeCesA.5.The plant overexpression vectors named pCAMBIA1303-N-BeBeCesA3,4 was successfully constructed,and pCAMBIA1303-N-BeBeCesA4 was successfully transformed into Populus tomentosa by agrobacterium mediated.9 transgenic positive plants were obtained,of which 7 plants have higher expression of BeCesA4.The plant height,leaf length and leaf width of transgenic positive plants are significantly higher than that of control,but the cellulose content is significantly lower than that of control.