Search

Summary: Tassel branch number (TBN) is a key agronomic trait for adapting to high‐density planting and grain yield in maize. However, the molecular regulatory mechanisms underlying tassel branching are still largely unknown.Here, we used molecular and genetic studies together to show that ZmELF3.1 plays a critical role in regulating TBN in maize.Previous studies showed that ZmELF3.1 forms the evening complex through interacting with ZmELF4 and ZmLUX to regulate flowering in maize and that RA2 and TSH4 (ZmSBP2) suppresses and promotes TBN in maize, respectively. In this study, we show that loss‐of‐function mutants of ZmELF3.1 exhibit a significant increase of TBN. We also show that RA2 directly binds to the promoter of TSH4 and represses its expression, thus leading to reduced TBN. We further demonstrate that ZmELF3.1 directly interacts with both RA2 and ZmELF4.2 to form tri‐protein complexes that further enhance the binding of RA2 to the promoter of TSH4, leading to suppressed TSH4 expression and consequently decreased TBN.Our combined results establish a novel functional link between the ELF3‐ELF4‐RA2 complex and miR156‐SPL regulatory module in regulating tassel branching and provide a valuable target for genetic improvement of tassel branching in maize. [ABSTRACT FROM AUTHOR]

Little is known about the transport mechanism of intracellular auxin. Here, we report two vacuole-localized proteins, Oryza sativa Os CONTINUOUS VASCULAR RING- LIKE 1 (Os COLE1) and Os COLE1- INTERACTING PROTEIN (Os CLIP), that regulate intracellular auxin transport and homoeostasis., Overexpression of Os COLE1 markedly increased the internode length and auxin content of the stem base, whereas these parameters were decreased in RNA interference ( RNAi) plants. Os COLE1 was localized on the tonoplast and preferentially expressed in mature tissues. We further identified its interacting protein Os CLIP, which was co-localized on the tonoplast., Protein−protein binding assays demonstrated that the N-terminus of Os COLE1 directly interacted with Os CLIP in yeast cells and the rice protoplast. Furthermore, 3H-indole-3-acetic acid (3H- IAA) transport assays revealed that Os CLIP transported IAA into yeast cells, which was promoted by Os COLE1., The results indicate that Os COLE1 affects rice development by regulating intracellular auxin transport through interaction with Os CLIP, which provides a new insight into the regulatory mechanism of intracellular transport of auxin and the roles of vacuoles in plant development. [ABSTRACT FROM AUTHOR]

Previous studies have identified miR169/NF-YA modules are important regulators of plant development and stress responses. Currently, reported genome sequence data offers an opportunity for global characterization of miR169 and NF-YA genes, which may provide insights into the molecular mechanisms of the miR169/NF-YA modules in maize. In our study, fourteen NF-YA transcription factors with conserved domains were identified based on maize genome loci. The miR169 gene family has 18 members that generate 10 mature products, and 8 of these mature miR169 members could target 7 of 14 ZmNF-YA genes in maize. The seven ZmNF-YA proteins were localized to the nucleus while lacked transcriptional activity. We investigated the expression patterns of the zma-miR169 members and their targeted ZmNF-YA genes in maize roots treated by drought stress (polyethylene glycol, PEG), hormone stress (abscisic acid, ABA), and salt stress (NaCl). The zma-miR169 family members were downregulated in short term (0∼48 h) and generally upregulated over the long term (15 days) in response to the three abiotic stress conditions. Most of the targeted ZmNF-YA genes exhibited a reverse correlation with zma-miR169 gene expression over both the short term and long term. Maize root elongation was promoted by PEG and ABA but repressed by NaCl over the long term. Apparently, ZmNF-YA14 expression perfectly matched the zma-miR169 expression and corresponded to root growth reversely. [ABSTRACT FROM AUTHOR]

Salt stress significantly reduces the productivity of crop plants including maize (Zea mays). miRNAs are major regulators of plant growth and stress responses, but few studies have examined the potential impacts of miRNAs on salt stress responses in maize. Here, we show that ZmmiR169q is responsive to stress-induced ROS signals. After detecting that salt stress and exogenous H2O2 treatment reduced the accumulation of ZmmiR169q, stress assays with transgenic materials showed that depleting ZmmiR169q increased seedling salt tolerance whereas overexpressing ZmmiR169q decreased salt tolerance. Helping explain these observations, we found that ZmmiR169q repressed the transcript abundance of its target NUCLEAR FACTOR YA8 (ZmNF-YA8), and overexpression of ZmNF-YA8 in maize improved salt tolerance, specifically by transcriptionally activating the expression of the efficient antioxidant enzyme PEROXIDASE1. Our study reveals a direct functional link between salt stress and a miR169q-NF-YA8 regulatory module that plants use to manage ROS stress and strongly suggests that ZmNF-YA8 can be harnessed as a resource for developing salt-tolerant crop varieties., (© The Author(s) 2021. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Plants tend to flower earlier if placed under stress conditions. Those stress factors include drought, high salinity, low temperature, high- or low-intensity light, and ultraviolet light. This phenomenon has been called stress-induced flowering. Stress-induced plant flowering might be helpful for species preservation. Thus, stress-induced flowering might have biological significance and should be considered as important as other plant flowering control strategy. Here, history of stress-induced flowering, metabolic regulation and molecular regulation mechanisms in plants were reviewed. Potential perspective was discussed.

Little is known about the transport mechanism of intracellular auxin. Here, we report two vacuole-localized proteins, Oryza sativa OsCONTINUOUS VASCULAR RING-LIKE 1 (OsCOLE1) and OsCOLE1-INTERACTING PROTEIN (OsCLIP), that regulate intracellular auxin transport and homoeostasis. Overexpression of OsCOLE1 markedly increased the internode length and auxin content of the stem base, whereas these parameters were decreased in RNA interference (RNAi) plants. OsCOLE1 was localized on the tonoplast and preferentially expressed in mature tissues. We further identified its interacting protein OsCLIP, which was co-localized on the tonoplast. Protein-protein binding assays demonstrated that the N-terminus of OsCOLE1 directly interacted with OsCLIP in yeast cells and the rice protoplast. Furthermore, (3) H-indole-3-acetic acid ((3) H-IAA) transport assays revealed that OsCLIP transported IAA into yeast cells, which was promoted by OsCOLE1. The results indicate that OsCOLE1 affects rice development by regulating intracellular auxin transport through interaction with OsCLIP, which provides a new insight into the regulatory mechanism of intracellular transport of auxin and the roles of vacuoles in plant development., (© 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.)