Functional validation of the drought-responsive rice transcription factor "no apical meristem" (OsNAM12.1)

Date

6-2018

Abstract

The rice gene for transcription factor No Apical Meristem (OsNAM12.1) plays a central role in rice yield under drought through a network of co-localized genes at the QTL qDTY12.1. In this study, OsNAM12.1 was demonstrated to effectively transactivate a reporter gene via transient expression assays in rice and tobacco protoplasts. Transactivation activity of OsNAM12.1 using a yeast system was not successful in earlier studies. However, transactivation in a plant-based system suggests that plant-specific protein post translational modifications (PTMs) may be essential for this function. The OsNAM12.1 PTM, as profiled by 1-dimensional immuno-detected bands showed differences in band pattern between three rice varieties Vandana, Way Rarem and the near isogenic line (NIL) 481-B under well-watered and drought conditions. The differential band pattern suggested that the in silico predicted PT of SUMOylation phosphorylation and/or oligomerization may underpin these differences. In addition to transactivation and PTM studies, expression analysis in IR64+qDTY2.3 and IR64+qDTY12.1/2.3 near isogenic lines showed that OsNAM12.1 is upregulated two-fold under drought. Thus suggesting that OsNAM12.1. may be transcriptionally regulated by a gene or a set of genes found in qDTY2.3. Preliminary expression analyses exhibited that some qDTY2.3 putative candidate genes may indeed have a role in transcriptional regulation of OsNAM12.1. Further analyses have showed a MAPKK gene to be the most probable candidate gene responsible for such regulation of OsNAM12.1.

Document Type

Dissertation

Degree

Doctor of Philosophy in Genetics

College

Graduate School (GS)

Adviser/Committee Chair

Merlyn S. Mendioro

Co-adviser

Ajay Kohli

Committee Member

Maribel L. Dionisio-Sese, Ma. Genaleen Q. Diaz

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

En – AGROVOC descriptors

ORYZA SATIVA; GENES; APICAL MERISTEMS; TRANSCRIPTION FACTORS; FUNCTIONAL ANALYSIS; DROUGHT STRESS

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