Light signal provides the spatial and temporal information for plants to adapt to the prevailing environmental conditions. Alterations in light quality and quantity can trigger robust changes in global gene expression. In
The catalytic activity of mitogen‐activated protein kinases (
- NSF-PAR ID:
- 10083813
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 97
- Issue:
- 5
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 970-983
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
more » « less
Summary Arabidopsis thaliana , two groups of key factors regulating those changes in gene expression areCONSTITUTIVE PHOTOMORPHOGENESIS /DEETIOLATED /FUSCA (COP /DET /FUS ) and a subset of basic helix‐loop‐helix transcription factors calledPHYTOCHROME ‐INTERACTING FACTORS (PIF s). Recently, rapid progress has been made in characterizing the E3 ubiquitin ligases for the light‐induced degradation ofPIF 1,PIF 3 andPIF 4; however, the E3 ligase(s) forPIF 5 remains unknown. Here, we show that theCUL 4COP 1–SPA complex is necessary for the red light‐induced degradation ofPIF 5. Furthermore,COP 1 andSPA proteins stabilizePIF 5 in the dark, but promote the ubiquitination and degradation ofPIF 5 in response to red light through the 26S proteasome pathway. Genetic analysis illustrates that overexpression ofPIF 5cop1‐4 andspaQ seedling de‐etiolation phenotypes under dark and red‐light conditions. In addition, thePIF 5 protein level cycles under both diurnal and constant light conditions, which is also defective in thecop1‐4 andspaQ backgrounds. Bothcop1‐4 andspaQ show defects in diurnal growth pattern. Overexpression ofPIF 5cop1‐4 andspaQ under diurnal conditions, suggesting that theCOP 1–SPA complex plays an essential role in photoperiodic hypocotyl growth, partly through regulating thePIF 5 level. Taken together, our data illustrate how theCUL 4COP 1–SPA E3 ligase dynamically controls thePIF 5 level to regulate plant development. -
more » « less
Summary Plant small
RNA s (sRNA s) modulate key physiological mechanisms through post‐transcriptional and transcriptional silencing of gene expression. SmallRNA s fall into two major categories: those are reliant onRNA ‐dependentRNA polymerases (RDR RDR 12 /6 ‐dependentsRNA s include phased and repeat‐associated short interferingRNA s, while knownRDR 12 /6 ‐independentsRNA s are primarily microRNA s (miRNA ) and other hairpin‐derivedsRNA s. In this study we produced and analyzedsRNA ‐seq libraries fromrdr1 /rdr2 /rdr6 triple mutant plants. We found 58 previously annotated miRNA loci that were reliant onRDR 12 , or ‐6 function, casting doubt on their classification. We also found 38RDR 12 /6‐independentsRNA loci that are notMIRNA sRNA biogenesis. These 38sRNA ‐producing loci have as‐yet‐undescribed biogenesis mechanisms, and are frequently located in the vicinity of protein‐coding genes. Altogether, our analysis suggests that these 38 loci represent one or more undescribed types ofsRNA inArabidopsis thaliana . -
more » « less
Summary Plant lateral organ development is a complex process involving both transcriptional activation and repression mechanisms. The
WOX transcriptional repressorWOX 1/STF , theLEUNIG (LUG ) transcriptional corepressor and theANGUSTIFOLIA 3 (AN 3) transcriptional coactivator play important roles in leaf blade outgrowth and flower development, but how these factors coordinate their activities remains unclear. Here we report physical and genetic interactions among these key regulators of leaf and flower development.We developed a novel
in planta transcriptional activation/repression assay and suggest thatLUG could function as a transcriptional coactivator during leaf blade development.Mt
LUG physically interacts with MtAN 3, and this interaction appears to be required for leaf and flower development. A single amino acid substitution at position 61 in theSNH domain of MtAN 3 protein abolishes its interaction with MtLUG , and its transactivation activity and biological function. Mutations inlug andan3 enhanced each other's mutant phenotypes. Both thelug and thean3 mutations enhanced thewox1 prs leaf and flower phenotypes inArabidopsis .Our findings together suggest that transcriptional repression and activation mediated by the
WOX ,LUG andAN 3 regulators function in concert to promote leaf and flower development, providing novel mechanistic insights into the complex regulation of plant lateral organ development. -
more » « less
Abstract Fatty acid amide hydrolase (FAAH) is a conserved amidase that is known to modulate the levels of endogenous
N ‐acylethanolamines (NAEs) in both plants and animals. The activity of FAAH is enhancedin vitro by synthetic phenoxyacylethanolamides resulting in greater hydrolysis of NAEs. Previously, 3‐n ‐pentadecylphenolethanolamide (PDP‐EA) was shown to exert positive effects on the development of Arabidopsis seedlings by enhancing Arabidopsis FAAH (AtFAAH) activity. However, there is little information regarding FAAH activity and the impact of PDP‐EA in the development of seedlings of other plant species. Here, we examined the effects of PDP‐EA on growth of upland cotton (Gossypium hirsutum AtFAAH . Independent transgenic events showed accelerated true‐leaf emergence compared with non‐transgenic controls. Exogenous applications of PDP‐EA led to increases in overall seedling growth in AtFAAH transgenic lines. These enhanced‐growth phenotypes coincided with elevated FAAH activities toward NAEs and NAE oxylipins. Conversely, the endogenous contents of NAEs and NAE‐oxylipin species, especially linoleoylethanolamide and 9‐hydroxy linoleoylethanolamide, were lower in PDP‐EA treated seedlings than in controls. Further, transcripts for endogenous cottonFAAH genes were increased following PDP‐EA exposure. Collectively, our data corroborate that the enhancement of FAAH enzyme activity by PDP‐EA stimulates NAE‐hydrolysis and that this results in enhanced growth in seedlings of a perennial crop species, extending the role of NAE metabolism in seedling development beyond the model annual plant species,Arabidopsis thaliana -
more » « less
Summary The mitochondrial and chloroplast
mRNA s of the majority of land plants are modified through cytidine to uridine (C‐to‐U)RNA editing. Previously, forward and reverse genetic screens demonstrated a requirement for pentatricopeptide repeat (PPR ) proteins forRNA editing. Moreover, chloroplast editing factorsOZ 1,RIP 2,RIP 9 andORRM 1 were identified in co‐immunoprecipitation (co‐IP) experiments, albeit the minimal complex sufficient for editing activity was never deduced. The current study focuses on isolated, intact complexes that are capable of editing distinct sites. Peak editing activity for four sites was discovered in size‐exclusion chromatography (SEC) fractions ≥ 670 kDa, while fractions estimated to be approximately 413 kDa exhibited the greatest ability to convert a substrate containing the editing siterps14 C80.RNA content peaked in the ≥ 670 kDa fraction. Treatment of active chloroplast extracts withRN ase A abolished the relationship of editing activity with high‐MW fractions, suggesting a structuralRNA component in native complexes. By immunoblotting,RIP 9,OTP 86,OZ 1 andORRM 1 were shown to be present in active gel filtration fractions, thoughOZ 1 andORRM 1 were mainly found in low‐MW inactive fractions. Active editing factor complexes were affinity‐purified using anti‐RIP 9 antibodies, and orthologs to putativeArabidopsis thaliana RNA editing factorPPR proteins,RIP 2,RIP 9,RIP 1,OZ 1,ORRM 1 andISE 2 were identified via mass spectrometry. Western blots from co‐IP studies revealed the mutual association ofOTP 86 andOZ 1 with nativeRIP 9 complexes. Thus,RIP 9 complexes were discovered to be highly associated with C‐to‐URNA editing activity and other editing factors indicative of their critical role in vascular plant editosomes.
