Leaf senescence, which is the final process of leaf development, involves a complex regulation of thousands of genes to recover and recycle valuable nutrients and mobilize them to growing part of the plant for high yield of fruits and grains. A greater understanding of the complex senescence gene regulation could be helpful for higher crop yield. This study is focused on three genes (ATX1, ATX3 and ATX4) that code for H3K4me3 methyl transferases to investigate their effect on flowering transition time, and their importance during senescence by assaying total chlorophyll and protein levels, and quantifying the mRNA expression of senescence marker gene WRKY75. An additive early flowering phenotype was observed for double mutants. However, no senescence alteration was found for double mutants. An increased level of total chlorophyll was shown by single mutant atx4. Significant differences for total protein were observed in leaf 6 vs. leaf 7 for double mutants atx1atx3 and atx1atx4, suggesting a faster protein degradation rate or smaller variability (reduced confidence interval) in leaf 7 data. Due to the gene redundancy of the ten-member ATX family, knocking out two genes may not adequately affect the function of H3K4 methyltransferase activity. Therefore, phenotypic analyses of triple and quadruple mutants of senescence-expressed H3K4me3 methyltransferase coding genes may show stronger senescence phenotypes. Of importance, these data show that significantly early flowering does not dictate early leaf senescence.
|Commitee:||Eldon, Elizabeth, Fraser, Deborah|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 56/04M(E), Masters Abstracts International|
|Keywords:||Arabidopsis, H3K4me3, Methyltransferases, Mutants, Phenotype, Senescence|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be