Life Sciences Commons^™

Correct developmental timing is essential for plant fitness and reproductive success. Two important transitions in shoot development—the juvenile-to-adult vegetative transition and the vegetative-to-reproductive transition—are mediated by a group of genes targeted by miR156, SQUAMOSA PROMOTER BINDING PROTEIN (SBP) genes. To determine the developmental functions of these genes in Arabidopsis thaliana, we characterized their expression patterns, and their gain-of-function and loss-of-function phenotypes. Our results reveal that SBP-LIKE (SPL) genes in Arabidopsis can be divided into three functionally distinct groups: 1) SPL2, SPL9, SPL10, SPL11, SPL13 and SPL15 contribute to both the juvenile-to-adult vegetative transition and the vegetative-to-reproductive transition, with SPL9, SP13 …

Developing seedlings are well equipped to alter their growth in response to external factors in order to maximize their chances of survival. SUPPRESSOR OF PHYTOCHROME B4-#3 (SOB3) and other members of the AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) family of transcription factors modulate the development of Arabidopsis (Arabidopsis thaliana) by repressing hypocotyl elongation in young seedlings growing in light. However, the molecular mechanism behind how AHLs influence seedling development is largely unknown. We have identified genes associated with auxin-mediated hypocotyl elongation as downstream targets of SOB3. We found that YUCCA8 (YUC8) as well as members of the SMALL AUXIN UP-REGULATED …

The Arabidopsis thaliana hypocotyl is a robust system for studying the interplay of light and plant hormones, such as brassinosteroids (BRs), in the regulation of plant growth and development. Since BRs cannot be transported between plant tissues, their cellular levels must be appropriate for given developmental fates. BR homeostasis is

maintained in part by transcriptional feedback regulation loops that control the expression of key metabolic enzymes, including the BRinactivating enzymes BAS1 (CYP734A1, formerly CYP72B1) and SOB7 (CYP72C1). Here, we find that the NAC transcription factor (TF) ATAF2 binds the promoters of BAS1 and SOB7 to suppress their expression. ATAF2 restricts …

Background:

Members of the ancient land-plant-specific transcription factor AT-Hook Motif Nuclear Localized (AHL)

gene family regulate various biological processes. However, the relationships among the AHL genes, as well as their evolutionary history, still remain unexplored.

Results:

We analyzed over 500 AHL genes from 19 land plant species, ranging from the early diverging Physcomitrella

patens and Selaginella to a variety of monocot and dicot flowering plants. We classified the AHL proteins into three types (Type-I/-II/-III) based on the number and composition of their functional domains, the AT-hook motif(s) and PPC domain. We further inferred their phylogenies via Bayesian inference analysis and …

The Arabidopsis thaliana genome encodes 29 AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) genes, which evolved into two phylogenic clades. The AHL proteins contain one or two AT-hook motif(s) and one plant and prokaryote conserved (PPC)/domain of unknown function #296 (DUF296) domain. Seedlings lacking both SOB3/AHL29 and ESC/AHL27 confer a subtle long-hypocotyl phenotype compared with the WT or either single-null mutant. In contrast, the missense allele sob3-6 confers a dramatic long-hypocotyl phenotype in the light. In this study, we examined the dominant-negative feature of sob3-6 and found that it encodes a protein with a disrupted AT-hook motif that abolishes binding to …