Molecular Mechanisms Study On The Development Of Apical Bud And Vascular Tissue Regulated By PtSHRs Gene

The GRAS family is a class of plant-specific transcription factor,which plays an important role in plant growth and development.The GRAS family contains 8 subfamilies: DELLA,HAM,LISCL,PAT1,LS,SCR,SHR and SCL3.Different subfamilies play different roles in the process of plant growth.SHORT-ROOT(SHR)is a key component in a developmental pathway regulating the specification of the root stem cell niche as well as the radial patterning of the root in plant.SHR gene also regulates a range of genes,mediates many important signal pathways,and participates in a variety of physiological processes.To specify the functions of PtSHRs gene,PtSHR1 gene and PtSHR2 gene were introduced into wild poplar(INRA717 1-B4)by Agrobacterium-mediated transformation.Each transgenic poplar was analyzed by semi-quantitative reverse transcription and real-time quantitative PCR.The transgenic poplar with the highest expression and the medium of expression was selected for transplanting,morphological observation and growth data.The results showed that the development of apical bud of poplar and plant growth were repressed by the over expression of PtSHRs gene.The above-mentioned transgenic poplar was transplanted for 8 weeks and stained at the 3rd,6th and 9th internode sections.The results showed that the over expression of PtSHRs gene also influence the development of vascular tissue of transgenic poplar.Study on related genes in the development of apical bud and vascular tissue of transgenic poplar by real-time quantitative PCR after transplanting 8 weeks.The results showed that PtSHRs gene influenced the development of transgenic poplar buds by inhibiting the expression of WUS gene,influenced the development of vascular tissue of poplar by inhibiting the expression of STM gene,and influenced the plant growth by inhibiting the expression of PIN1 gene.To further verify the functions of PtSHRs gene,PtSHR1 gene and PtSHR2 gene are transferred into Arabidopsis by Agrobacterium-mediated transformation.Each transgenic Arabidopsis is analyzed by semi-quantitative reverse transcription and real-time quantitative PCR.The Over-expression and Medium-expression of PtSHRs gene in transgenic Arabidopsis were selected to morphological observation and statistics.The results showed that the development of apical bud of Arabidopsis was repressed by the overexpression of PtSHRs gene at the early growth stage,Accompanied by bolting delay,increased leaf and increased axillary bud rate.Observe apical bud of transgenic Arabidopsis analysis after transplanting 2 days by semi-thin sectioning.The results showed that the overexpression of PtSHRs gene influenced the development of apical meristem of transgenic Arabidopsis.Then analysis the tissue sections of the stem and hypocotyl of transgenic Arabidopsis after transplanting 40 days.The results showed that the overexpression of PtSHRs gene also influenced the development of vascular tissue of transgenic Arabidopsis.Study on related genes in the development of apical bud and vascular tissue of transgenic Arabidopsis by real-time quantitative PCR after transplanting 2 days and 40 days.The results showed that PtSHRs gene influenced the development of apical bud of Arabidopsis by inhibiting the expression of WUS gene,the development of secondary xylem of Arabidopsis by inhibiting the expression of STM gene and the plant growth by inhibiting the expression of PIN1 gene.This paper,further supplemented the function of SHR gene,which based on the study of transgenic poplar and transgenic Arabidopsis over-expressing Pt SHRs gene,provided the experimental basis for the study of plant budding and vascular tissue,and offered some guidance on the improvement of timber structure.