Abstract
The effect of T-DNA insertion in the 3'-UTR region of Arabidopsis thaliana At3g58450 gene encoding the Germination-Related Universal Stress Protein (GRUSP) was studied. It was found that under a long-day condition this mutation delays transition to flowering of grusp-115 transgenic line that due to a reduced content of endogenous bioactive gibberellins GA1 and GA3 in comparison to the wild-type plants (Col-0). Exogenous GA accelerated flowering of both lines but did not change the time of difference in the onset of flowering between Col-0 and grusp-115. In addition to changes in GA metabolism, grusp-115 evidently has disturbances in realization of the signal that induces flowering. This is confirmed by the results of gene expression of the floral integrator FLOWERING LOCUS T (FT) and the floral repressor FLOWERING LOCUS C (FLC), which are key flowering regulators and acting opposite. We hypothesize that the formation of grusp-115 phenotype can also be affected by a low expression level of FT due to up-regulated FLC expression.
Highlights
The effect of T-DNA insertion in the 3'-UTR region of Arabidopsis thaliana At3g58450 gene encoding the Germination-Related Universal Stress Protein (GRUSP) was studied
GRUSP protein (Germination-Related Universal Stress Protein) encoded by At3g58450 gene A. thaliana [12, 13] is a potential member in pathways controlling the balance between abscisic acid (ABA) and GA throughout different growth stages
The aim of this study is to analyze for the first time the relationship of a late-flowering phenotype of grusp-115 transgenic line, characterized by suppressed expression of At3g58450 due to T-DNA insertion in the 3'-UTR, with the endogenous gibberellins content, as well as with the expression of genes that control the transition to reproductive development
Summary
We used A. thaliana (L.) Heynh ecotype Columbia wild type (Col-0) and GABI_kat 115C08 (grusp-115) homozygous transgenic line [12]. From studies using an isotope label, it is known that exogenously applied GAs are effectively absorbed by leaves and subsequently transported to the shoot apex in their bioactive form [16]. The stem elongation in Col-0 began 3–5 days after the emergence of a flower bud, while in grusp-115, this did not occur, and the head of inflorescence remained longer inside of rosette leaves (Fig. 1b; number 2 corresponds to 35-day-old plants). In our study, during vegetative growth, Col-0 plants formed on average 11 rosette leaves, while grusp-115 started flowering in only about 14 leaves (Fig. 3a). The delay in transition to flowering, expressed in a number of rosette leaves, was completely eliminated in grusp-115 after treatment of plants with exogenous gibberellins.
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