https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:44997 trans-acting small-interfering RNA (tasiRNA) production allowed for use of the loss-of-function mutant lines, drb1, drb2, drb4, and ago7, to further functionally characterize the TAS3 pathway in Arabidopsis thaliana (Arabidopsis). Towards achieving this goal, we also describe the developmental and molecular phenotypes expressed by three newly generated Arabidopsis lines, the drb1ago7, drb2ago7, and drb4ago7 double mutants. We show that the previously reported developmental abnormalities displayed by the drb1, drb2, drb4, and ago7 single mutants, are further exacerbated in the drb1ago7, drb2ago7, and drb4ago7 double mutants, with rosette area, silique length, and seed set all impaired to a greater degree in the double mutants. Molecular assessment of the TAS3 pathway in the floral tissues of the seven analyzed mutants revealed that DRB1 is the sole DRB required for miR390 sRNA production. However, DRB2 and DRB4 appear to play secondary roles at this stage of the TAS3 pathway to ensure that miR390 sRNA levels are tightly maintained. We further show that the expression of the TAS3-derived tasiARF target genes, AUXIN RESPONSE FACTOR2 (ARF2), ARF3, and ARF4, was altered in drb1ago7, drb2ago7, and drb4ago7 flowers. Altered ARF2, ARF3, and ARF4 expression was in turn demonstrated to lead to changes in the level of expression of KAN1, KAN3, and KAN4, three KANADI transcription factor genes known to be transcriptionally regulated by ARF2, ARF3, and ARF4. Taken together, the demonstrated relationship between altered ARF and KAN gene expression in drb1ago7, drb2ago7 and drb4ago7 flowers, could, in part, explain the more severe developmental defects displayed by the double mutants, compared to milder impact that loss of only a single piece of TAS3 pathway protein machinery was demonstrated to have on drb1, drb2, drb4 and ago7 reproductive development.]]> Wed 26 Oct 2022 09:28:43 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:48593 Wed 22 Mar 2023 08:46:40 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:38723 Wed 19 Jan 2022 10:04:17 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:55327 Wed 15 May 2024 15:48:41 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29329 Wed 11 Apr 2018 13:14:56 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:50712 Wed 02 Aug 2023 15:42:45 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49855 Tue 06 Jun 2023 15:03:36 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43784 Thu 29 Sep 2022 14:15:59 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:52099 Thu 28 Sep 2023 14:50:07 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:45368 Thu 27 Oct 2022 15:02:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:42559 Thu 25 Aug 2022 11:05:11 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:33146 Poaceae family of grasses, namely; maize (Zea mays L.), wheat (Triticum aestivum L.) and rice (Oryza sativa L.). It is, therefore, of significant concern that all three of these Poaceae grass species are susceptible to a range of abiotic stresses, including drought and salt stress. Highly conserved among monocotyledonous and dicotyledonous plant species, microRNAs (miRNAs) are now well-established master regulators of gene expression, influencing all aspects of plant development, mediating defense responses against pathogens and adaptation to environmental stress. Here we investigate the variation in the abundance profiles of six known abiotic stress-responsive miRNAs, following exposure to salt and drought stress across these three key Poaceae grass crop species as well as to compare these profiles to those obtained from the well-established genetic model plant species, Arabidopsis thaliana (L.) Heynh. Additionally, we outline the variables that are the most likely primary contributors to instances of differential miRNA abundance across the assessed species following drought or salt stress exposure, specifically; (1) identifying variations in the experimental conditions and/or methodology used to assess miRNA abundance, and; (2) the distribution of regulatory transcription factor binding sites within the putative promoter region of a MICRORNA (MIR) gene that encodes the highly conserved, stress-responsive miRNA. We also discuss the emerging role that non-conserved, species-specific miRNAs play in mediating a plant’s response to drought or salt stress.]]> Thu 21 Oct 2021 12:52:38 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:37780 Arabidopsis thaliana (Arabidopsis) can be readily molecularly manipulated, therefore offering an excellent experimental system to alter the profile of abiotic stress responsive miRNA/target gene expression modules to determine whether such modification enables Arabidopsis to express an altered abiotic stress response phenotype. Towards this goal, high throughput sequencing was used to profile the miRNA landscape of Arabidopsis whole seedlings exposed to heat, drought and salt stress, and identified 121, 123 and 118 miRNAs with a greater than 2-fold altered abundance, respectively. Quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) was next employed to experimentally validate miRNA abundance fold changes, and to document reciprocal expression trends for the target genes of miRNAs determined abiotic stress responsive. RT-qPCR also demonstrated that each miRNA/target gene expression module determined to be abiotic stress responsive in Arabidopsis whole seedlings was reflective of altered miRNA/target gene abundance in Arabidopsis root and shoot tissues post salt stress exposure. Taken together, the data presented here offers an excellent starting platform to identify the miRNA/target gene expression modules for future molecular manipulation to generate plant lines that display an altered response phenotype to abiotic stress.]]> Thu 21 Oct 2021 12:52:36 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:53263 Mon 20 Nov 2023 12:14:18 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49409 Fri 12 May 2023 14:55:34 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:49797 Fri 02 Jun 2023 17:08:29 AEST ]]>