Identification of Arabidopsis stay-green mutants with a functional ethylene-response pathway

2010 ◽  
Vol 14 ◽  
pp. 119-129
Author(s):  
R. Shirzadian-Khorramabad ◽  
H.C. Jing ◽  
J. Hille ◽  
P.P. Dijkwel
Keyword(s):  
Shelf Life ◽  
Leaf Senescence ◽  
Plant Hormone ◽  
Floral Induction ◽  
Growth Conditions ◽  
Pleiotropic Effects ◽  
Wild Type ◽  
Stay Green ◽  
Ethylene Response ◽  
Determinant Factor

Natural or harvest-induced senescence is a major determinant factor causing crop losses. The plant hormone ethylene is a strong inducer of senescence and decreasing the ethylene response can reduce senescence, albeit often with undesirable pleiotropic effects. We took advantage of ethylene-induced leaf senescence as a tool to screen for late senescence Arabidopsis mutants that still have a functional ethylenesignalling pathway. Sixteen Arabidopsis onset of leaf death (old) mutants were selected that stayed green after treatment with ethylene. While all the mutants responded to ethylene in a triple response assay, ten mutants responded to the treatment in the same way as the wild type. These ten mutants showed limited pleiotropic effects when grown under standard growth conditions but nine mutants flowered slightly later than the wild type. Genetic characterisation of a subset of the mutants identified several independent loci controlling the leaf senescence process. The approach resulted in the isolation of several stay-green mutants with a functional ethylene response pathway. The late senescence mutants show extended leaf longevity and further research may advance the field of pre- or post-harvest senescence technology. The results, moreover, suggest that there is a correlation between senescence and floral induction. Keywords: Senescence, Arabidopsis, ethylene, mutant, shelf life

scholarly journals Ethylene response pathway is essential forARABIDOPSIS A-FIFTEENfunction in floral induction and leaf senescence

2012 ◽  
Vol 7 (4) ◽  
pp. 457-460 ◽  
Author(s):  
Guan-Hong Chen ◽  
Yuan-Li Chan ◽  
Chia-Ping Liu ◽  
Long-Chi Wang
Keyword(s):  
Leaf Senescence ◽  
Floral Induction ◽  
Ethylene Response

Effects of Exogenous ABA and 6-BA on Flag Leaf Senescence in Different Types of Stay-Green Wheat and Relevant Physiological Mechanisms

2013 ◽  
Vol 39 (6) ◽  
pp. 1096 ◽  
Author(s):  
Dong-Qing YANG ◽  
Zhen-Lin WANG ◽  
Yan-Ping YIN ◽  
Ying-Li NI ◽  
Wei-Bing YANG ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Flag Leaf ◽  
Physiological Mechanisms ◽  
Stay Green ◽  
Exogenous Aba ◽  
Different Types

scholarly journals The Lipid Lysyl-Phosphatidylglycerol Is Present in Membranes of Rhizobium tropici CIAT899 and Confers Increased Resistance to Polymyxin B Under Acidic Growth Conditions

2007 ◽  
Vol 20 (11) ◽  
pp. 1421-1430 ◽  
Author(s):  
Christian Sohlenkamp ◽  
Kanaan A. Galindo-Lagunas ◽  
Ziqiang Guan ◽  
Pablo Vinuesa ◽  
Sally Robinson ◽  
...  
Keyword(s):  
Sinorhizobium Meliloti ◽  
Minimal Medium ◽  
Polymyxin B ◽  
Growth Conditions ◽  
Membrane Lipid ◽  
Low Ph ◽  
Wild Type ◽  
Rhizobium Tropici ◽  
Gram Negative ◽  
Inducible Genes

Lysyl-phosphatidylglycerol (LPG) is a well-known membrane lipid in several gram-positive bacteria but is almost unheard of in gram-negative bacteria. In Staphylococcus aureus, the gene product of mprF is responsible for LPG formation. Low pH-inducible genes, termed lpiA, have been identified in the gram-negative α-proteobacteria Rhizobium tropici and Sinorhizobium medicae in screens for acid-sensitive mutants and they encode homologs of MprF. An analysis of the sequenced bacterial genomes reveals that genes coding for homologs of MprF from S. aureus are present in several classes of organisms throughout the bacterial kingdom. In this study, we show that the expression of lpiA from R. tropici in the heterologous hosts Escherichia coli and Sinorhizobium meliloti causes formation of LPG. A wild-type strain of R. tropici forms LPG (about 1% of the total lipids) when the cells are grown in minimal medium at pH 4.5 but not when grown in minimal medium at neutral pH or in complex tryptone yeast (TY) medium at either pH. LPG biosynthesis does not occur when lpiA is deleted and is restored upon complementation of lpiA-deficient mutants with a functional copy of the lpiA gene. When grown in the low-pH medium, lpiA-deficient rhizobial mutants are over four times more susceptible to the cationic peptide polymyxin B than the wild type.

scholarly journals The NALCN Channel Regulator UNC-80 Functions in a Subset of Interneurons To Regulate Caenorhabditis elegans Reversal Behavior

2019 ◽  
Vol 10 (1) ◽  
pp. 199-210 ◽  
Author(s):  
Chuanman Zhou ◽  
Jintao Luo ◽  
Xiaohui He ◽  
Qian Zhou ◽  
Yunxia He ◽  
...  
Keyword(s):  
Plant Hormone ◽  
Neuronal Excitability ◽  
Resting Membrane Potential ◽  
Loss Of Function ◽  
Wild Type ◽  
C Elegans ◽  
Link Type ◽  
Complex Functions ◽  
And Function ◽  
Multiple Loss

NALCN (Na+leak channel, non-selective) is a conserved, voltage-insensitive cation channel that regulates resting membrane potential and neuronal excitability. UNC79 and UNC80 are key regulators of the channel function. However, the behavioral effects of the channel complex are not entirely clear and the neurons in which the channel functions remain to be identified. In a forward genetic screen for C. elegans mutants with defective avoidance response to the plant hormone methyl salicylate (MeSa), we isolated multiple loss-of-function mutations in unc-80 and unc-79. C. elegans NALCN mutants exhibited similarly defective MeSa avoidance. Interestingly, NALCN, unc-80 and unc-79 mutants all showed wild type-like responses to other attractive or repelling odorants, suggesting that NALCN does not broadly affect odor detection or related forward and reversal behaviors. To understand in which neurons the channel functions, we determined the identities of a subset of unc-80-expressing neurons. We found that unc-79 and unc-80 are expressed and function in overlapping neurons, which verified previous assumptions. Neuron-specific transgene rescue and knockdown experiments suggest that the command interneurons AVA and AVE and the anterior guidepost neuron AVG can play a sufficient role in mediating unc-80 regulation of the MeSa avoidance. Though primarily based on genetic analyses, our results further imply that MeSa might activate NALCN by direct or indirect actions. Altogether, we provide an initial look into the key neurons in which the NALCN channel complex functions and identify a novel function of the channel in regulating C. elegans reversal behavior through command interneurons.

scholarly journals Isolation of a gene required for programmed initiation of development by Aspergillus nidulans.

1992 ◽  
Vol 12 (9) ◽  
pp. 3827-3833 ◽  
Author(s):  
T H Adams ◽  
W A Hide ◽  
L N Yager ◽  
B N Lee
Keyword(s):  
Life Cycle ◽  
Aspergillus Nidulans ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Nutrient Deprivation ◽  
Deletion Mutants ◽  
Wild Type ◽  
Microbial Development ◽  
Type Strains ◽  
Posttranscriptional Level

In contrast to many other cases in microbial development, Aspergillus nidulans conidiophore production initiates primarily as a programmed part of the life cycle rather than as a response to nutrient deprivation. Mutations in the acoD locus result in "fluffy" colonies that appear to grow faster than the wild type and proliferate as undifferentiated masses of vegetative cells. We show that unlike wild-type strains, acoD deletion mutants are unable to make conidiophores under optimal growth conditions but can be induced to conidiate when growth is nutritionally limited. The requirement for acoD in conidiophore development occurs prior to activation of brlA, a primary regulator of development. The acoD transcript is present both in vegetative hyphae prior to developmental induction and in developing cultures. However, the effects of acoD mutations are detectable only after developmental induction. We propose that acoD activity is primarily controlled at the posttranscriptional level and that it is required to direct developmentally specific changes that bring about growth inhibition and activation of brlA expression to result in conidiophore development.

scholarly journals A Screen for Genes That Function in Abscisic Acid Signaling in Arabidopsis thaliana

Genetics ◽  
2002 ◽  
Vol 161 (3) ◽  
pp. 1247-1255 ◽  
Author(s):  
Eiji Nambara ◽  
Masaharu Suzuki ◽  
Suzanne Abrams ◽  
Donald R McCarty ◽  
Yuji Kamiya ◽  
...  
Keyword(s):  
Abscisic Acid ◽  
Growth And Development ◽  
Plant Hormone ◽  
The Other ◽  
Aba Signaling ◽  
Wild Type ◽  
Plant Growth And Development ◽  
Diverse Range ◽  
Abscisic Acid Signaling ◽  
Aba Insensitive

Abstract The plant hormone abscisic acid (ABA) controls many aspects of plant growth and development under a diverse range of environmental conditions. To identify genes functioning in ABA signaling, we have carried out a screen for mutants that takes advantage of the ability of wild-type Arabidopsis seeds to respond to (−)-(R)-ABA, an enantiomer of the natural (+)-(S)-ABA. The premise of the screen was to identify mutations that preferentially alter their germination response in the presence of one stereoisomer vs. the other. Twenty-six mutants were identified and genetic analysis on 23 lines defines two new loci, designated CHOTTO1 and CHOTTO2, and a collection of new mutant alleles of the ABA-insensitive genes, ABI3, ABI4, and ABI5. The abi5 alleles are less sensitive to (+)-ABA than to (−)-ABA. In contrast, the abi3 alleles exhibit a variety of differences in response to the ABA isomers. Genetic and molecular analysis of these alleles suggests that the ABI3 transcription factor may perceive multiple ABA signals.

scholarly journals Arabidopsis NPF4.6 and NPF5.1 Control Leaf Stomatal Aperture by Regulating Abscisic Acid Transport

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 885
Author(s):  
Takafumi Shimizu ◽  
Yuri Kanno ◽  
Hiromi Suzuki ◽  
Shunsuke Watanabe ◽  
Mitsunori Seo
Keyword(s):  
Abscisic Acid ◽  
Plant Hormone ◽  
Leaf Surface ◽  
Stomatal Closure ◽  
Guard Cells ◽  
Cell Types ◽  
Acid Transport ◽  
Wild Type ◽  
Vascular Tissues ◽  
Abscisic Acid Transport

The plant hormone abscisic acid (ABA) is actively synthesized in vascular tissues and transported to guard cells to promote stomatal closure. Although several transmembrane ABA transporters have been identified, how the movement of ABA within plants is regulated is not fully understood. In this study, we determined that Arabidopsis NPF4.6, previously identified as an ABA transporter expressed in vascular tissues, is also present in guard cells and positively regulates stomatal closure in leaves. We also found that mutants defective in NPF5.1 had a higher leaf surface temperature compared to the wild type. Additionally, NPF5.1 mediated cellular ABA uptake when expressed in a heterologous yeast system. Promoter activities of NPF5.1 were detected in several leaf cell types. Taken together, these observations indicate that NPF5.1 negatively regulates stomatal closure by regulating the amount of ABA that can be transported from vascular tissues to guard cells.

Leaf Senescence in a Stay-Green Rice Variety, SNU-SG1 and a Mutant, sgr

2008 ◽  
pp. 1515-1518
Author(s):  
Min-Hyuk Oh ◽  
Tae-Shik Park ◽  
Woon-Ho Yang ◽  
Kang-Su Kwak ◽  
Jin-Chul Shin ◽  
...  
Keyword(s):  
Leaf Senescence ◽  
Rice Variety ◽  
Stay Green

scholarly journals Genetics and Genomic basis of Stay-green Trait

2021 ◽  
Vol 14 (2) ◽  
Author(s):  
Harshavardan J Hilli
Keyword(s):  
Transcription Factors ◽  
Leaf Senescence ◽  
Genetic Improvement ◽  
Physiological Role ◽  
Dimensional Approach ◽  
Stay Green ◽  
Chlorophyll Pigment ◽  
Yield Gain ◽  
Genomic Basis ◽  
Potential Use

Staygreen is one such trait in which genotypes possessing this trait maintain more photo synthetically active leaves (& less senescent) than genotypes not possessing this trait. Delay of leaf senescence also known as stay-green character, has been identified as an important component in the genetic improvement of several crops to promote stress tolerance and yield gain. Although the stay-green phenotype is superficially similar in all species and genotypes, the genetic and physiological routes the traits are diverse. Photosynthetically active leaves for longer period depends on the concentration of chlorophyll pigment absorbing sunlight for photosynthesis. An multi dimensional approach for studying the senescence pathway rather than studying only the physiological role made a significant role in improvement. Hence new approaches like genomics, proteomics and metabolomics studies are necessary to understand the various transcription factors involved in regulating the leaf senescence process. Therefore, this review has aimed to bring light to major aspects of the stay-green character, showing its potential use in plant breeding.

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