Abstract Detail

Recent Topics Posters

Zhang, Yunan [1], Miao, Sen [2], Gou, Xiaoping [3], Tian, Hui Qiao [1], RUSSELL , SCOTT D [2].

Transcriptional Profiling of the Unfertilized Egg, Fertilized Egg and Early Zygote of Rice.

The maternal to zygotic transition (MZT) of plants during in vivo fertilization has only recently been within the reach of genomic analysis.  Using the Affymetrix 57K rice chip, we analyzed RNA isolated from microdissected mature egg cells, sperm cells, newly-fertilized egg cells (1 hr after pollination) and early zygotes (2.5 hr after pollination).  Prior studies have reported conflicting amounts of new expression and suggest that flowering plants may diverge from the protracted maternal contribution reported in the MZT of model animal systems.  Rice (Oryza sativa) was chosen, as whole, intact gametes and zygotes could be collected and because of the rich genomic information available for rice.  Very significantly (p<0.001) differentially-upregulated transcripts in the egg and zygote (1.2-fold or greater), as compared with other gametophytic and sporophytic tissues, were selected as potentially interesting candidate genes and their pattern of expressional change was compared.  Changes in transcript signal intensity in these transcripts where normalized over the genome and examined prior to fertilization and during early post-fertilization stages.  These egg-cell/zygote-responsive genes showed transient increases in signal intensity in the newly-fertilized egg cell.  Most of these transcripts, however, displayed a marked decrease in average signal intensity between the unfertilized and fertilized egg cell followed by an increase in the early zygote.  Since the sperm cells have approximately a 1:1000 difference compared to the unfertilized egg cell, most potential increases in transcripts predicted from sperm expressional differences did not result in detectable increases in paternally-expressed genes.  Highly paternally-transcribed genes showed divergent patterns of expression, independent of initial transcription levels in the gametes, with most decreasing sharply in abundance.  Approximately equal numbers of newly-expressed probe set sequences were detected in the transition from the unfertilized to the fertilized egg as became undetectable during fertilization.  Relatively few new probe set sequences were detected immediately after nuclear fusion occurred in the zygote.  This occurrence of relatively few expressional changes immediately after syngamy suggests relatively few examples of new expression and decreases of prior abundant transcripts, potentially indicative of gradual upregulation of the pathways that are required for activation of the zygote and initiation of S-phase prior to the start of embryogenesis.

Related Links:
Rice Annotation site
Russell Lab Page

1 - Xiamen University, School of Life Sciences, Xiamen, 361005, China
2 - University Of Oklahoma, Department Of Microbiology And Plant Biology, 770 Van Vleet Oval, Norman, OK, 73019-6155, USA
3 - Lanzhou University, School of Life Sciences, Lanzhou, 730000, China

Keywords:
none specified

Presentation Type: Recent Topics Poster
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PRT050
Abstract ID:1836
Candidate for Awards:None