Functional analysis of glycin rich- RNA binding protein, a suppressor of trehalose-6-phosphate mediating growth arrest in Arabidopsis thaliana

ABSTRACT

Metabolism of the alpha-1,1 glucose disaccharide, trehalose, is indispensable in plants. In the Murashige and Skoog [MS] medium, trehalose inhibits plant growth and allocation of carbon to roots. A suppressor of trehalose-6-phosphate [T6P] mediated growth arrest, GR-RBP2, is characterized in more detail. Phylogenetic analysis revealed that GR-RBP2 is a protein of likely prokaryotic origin. A knockout mutant of GR-RBP2 was identified in the T-DNA insertion line SALK-059714, yet plants of this line were not altered with regard to growth on different carbon sources and on trehalose compared to WT. GUS expression analysis showed that GR-RBP2 was detected in adult leaves, flowers and siliques. Expression was particularly high in root tips. GR-RBP2 expression also is insensitive to 100 mM trehalose. TAP-tagged versions of this protein showed that GR-RBP2 is part of a protein complex in planta