Project description:The goal of this investigation was to identify putative targets of the TELOMERASE ACTIVATOR 1 transcription factor. Experiment Overall Design: Total RNA was isolated from leaves of 3 week old plants. We used three biological replicates of wild type (Columbia) and the tac1-1D activation tagged line (Ren et al., 2004. Plant Cell 16; 2910-2922).
Project description:This data is was generated in connection with a study on the 'Opposing influences of TAC1 and LAZY1 on Lateral Shoot Orientation in Arabidopsis'. RNA was extracted from individual shoot tips from wild type (Columbia; Col), tac1, and lazy1 plants that experienced either 0 or 45 minutes of gravistimulation by 90-degree reorientation. The summary of the entire project is as follows: TAC1 and LAZY1 are members of a gene family that regulates lateral shoot orientation in plants. TAC1 promotes outward orientations in response to light, while LAZY1 promotes upward shoot orientations in response to gravity via altered auxin transport. We performed genetic, molecular, and biochemical assays to investigate possible interactions between these genes. In Arabidopsis they were expressed in similar tissues and double mutants revealed the wide-angled lazy1 branch phenotype, indicating it is epistatic to the tac1 shoot phenotype. Surprisingly, the lack of TAC1 did not influence gravitropic shoot curvature responses. Combined, these results suggest TAC1 might negatively regulate LAZY1 to promote outward shoot orientations. However, additional results revealed that TAC1- and LAZY1 influence on shoot orientation is more complex than a simple direct negative regulatory pathway. Transcriptomes of Arabidopsis tac1 and lazy1 mutants compared to wild type under normal and gravistimulated conditions revealed few overlapping differentially expressed genes. Overexpression of each gene did not result in major branch angle differences. Shoot tip hormone levels were similar between tac1, lazy1, and Col, apart from exceptionally elevated levels of salicylic acid in lazy1. The data presented here provide a foundation for future study of TAC1 and LAZY1 regulation of shoot architecture.
