scholarly journals Long-Chain Polyisoprenoids Are Synthesized by AtCPT1 in Arabidopsis thaliana

Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2789 ◽  
Author(s):  
Przemyslaw Surowiecki ◽  
Agnieszka Onysk ◽  
Katarzyna Manko ◽  
Ewa Swiezewska ◽  
Liliana Surmacz

Arabidopsis roots accumulate a complex mixture of dolichols composed of three families, (i.e., short-, medium- and long-chain dolichols), but until now none of the cis-prenyltransferases (CPTs) predicted in the Arabidopsis genome has been considered responsible for their synthesis. In this report, using homo- and heterologous (yeast and tobacco) models, we have characterized the AtCPT1 gene (At2g23410) which encodes a CPT responsible for the formation of long-chain dolichols, Dol-18 to -23, with Dol-21 dominating, in Arabidopsis. The content of these dolichols was significantly reduced in AtCPT1 T-DNA insertion mutant lines and highly increased in AtCPT1-overexpressing plants. Similar to the majority of eukaryotic CPTs, AtCPT1 is localized to the endoplasmic reticulum (ER). Functional complementation tests using yeast rer2Δ or srt1Δ mutants devoid of medium- or long-chain dolichols, respectively, confirmed that this enzyme synthesizes long-chain dolichols, although the dolichol chains thus formed are somewhat shorter than those synthesized in planta. Moreover, AtCPT1 acts as a homomeric CPT and does not need LEW1 for its activity. AtCPT1 is the first plant CPT producing long-chain polyisoprenoids that does not form a complex with the NgBR/NUS1 homologue.

2013 ◽  
Vol 26 (8) ◽  
pp. 977-986 ◽  
Author(s):  
Carlos Augusto Avila ◽  
Lirio Milenka Arevalo-Soliz ◽  
Argelia Lorence ◽  
Fiona L. Goggin

Plant α-dioxygenases (α-DOX) are fatty acid–hydroperoxidases that contribute to the synthesis of oxylipins, a diverse group of compounds primarily generated through oxidation of linoleic (LA) and linolenic acid (LNA). Oxylipins are implicated in plant signaling against biotic and abiotic stresses. We report here that the potato aphid (Macrosiphum euphorbiae) induces Slα-DOX1 but not Slα-DOX2 expression in tomato (Solanum lycopersicum). Slα-DOX1 upregulation by aphids does not require either jasmonic acid (JA) or salicylic acid (SA) accumulation, since tomato mutants deficient in JA (spr2, acx1) or SA accumulation (NahG) still show Slα-DOX1 induction. Virus-induced gene silencing of Slα-DOX1 enhanced aphid population growth in wild-type (WT) plants, revealing that Slα-DOX1 contributes to basal resistance to aphids. Moreover, an even higher percent increase in aphid numbers occurred when Slα-DOX1 was silenced in spr2, a mutant line characterized by elevated LA levels, decreased LNA, and enhanced aphid resistance as compared with WT. These results suggest that aphid reproduction is influenced by oxylipins synthesized from LA by Slα-DOX1. In agreement with our experiments in tomato, two independent α-dox1 T-DNA insertion mutant lines in Arabidopsis thaliana also showed increased susceptibility to the green peach aphid (Myzus persicae), indicating that the role α-DOX is conserved in other plant-aphid interactions.


2018 ◽  
Vol 20 (1) ◽  
pp. 130 ◽  
Author(s):  
Le Luo ◽  
Ruyi Qin ◽  
Tao Liu ◽  
Ming Yu ◽  
Tingwen Yang ◽  
...  

Asparagine is one of the important amino acids for long-distance transport of nitrogen (N) in plants. However, little is known about the effect of asparagine on plant development, especially in crops. Here, a new T-DNA insertion mutant, asparagine synthetase 1 (asn1), was isolated and showed a different plant height, root length, and tiller number compared with wild type (WT). In asn1, the amount of asparagine decreased sharply while the total nitrogen (N) absorption was not influenced. In later stages, asn1 showed reduced tiller number, which resulted in suppressed tiller bud outgrowth. The relative expression of many genes involved in the asparagine metabolic pathways declined in accordance with the decreased amino acid concentration. The CRISPR/Cas9 mutant lines of OsASN1 showed similar phenotype with asn1. These results suggest that OsASN1 is involved in the regulation of rice development and is specific for tiller outgrowth.


Author(s):  
Bao-Zhen Zhao ◽  
Yang Yu ◽  
Zhi Yang ◽  
Qi Ding ◽  
Na Cui

Aims: SPS (Sucrose phosphate synthase) participates in plant growth and yield formation, and plays an important role in plant stress resistance. This study used T-DNA insertion mutant of AtSPS in Arabidopsis as test material. The growth indexes and soluble sugar contents of Arabidopsis thaliana under salt stress, osmotic stress and low temperature stress were determined, which laid the foundation for further understanding the mechanism of SPS in plant growth and development and abiotic stress resistance. Study Design: In order to analyze the mechanism of SPS in plant growth and development and abiotic stress resistance, this study used T-DNA insertion mutant of AtSPS in Arabidopsis as test material. The growth indexes and soluble sugar contents of Arabidopsis thaliana under salt stress, osmotic stress and low temperature stress were determined. Place and Duration of Study: College of Biological Science and Technology, between December 2020 and May 2021. Methodology: The contents of soluble sugar in tomato fruits were measured with HPLC (High performance liquid chromatography). The growth indexes were determined. Results: The results showed that AtSPS played positive regulation roles in seed germination and seedling growth of Arabidopsis thaliana. However, under abiotic stress conditions, AtSPS mutant increased the contents of soluble sugar, suggesting that Arabidopsis thaliana seedlings might improve resistance through osmotic regulating substances. Conclusion: AtSPS played positive regulation roles in seed germination and seedling growth of Arabidopsis. Meanwhile, AtSPS mutant increased the contents of soluble sugar to increase resistance of Arabidopsis under abiotic stresses, and the growth and development were blocked, suggesting that SPS was negative regulatory element to resist abiotic stress.


2017 ◽  
Author(s):  
Anne Osterrieder ◽  
Stan W Botchway ◽  
Andy Ward ◽  
Tijs Ketelaar ◽  
Norbert de Ruijter ◽  
...  

AbstractThe plant Golgi apparatus modifies and sorts incoming proteins from the endoplasmic reticulum (ER), and synthesises cell wall matrix material. Plant cells possess numerous motile Golgi bodies, which are connected to the ER by yet to be identified tethering factors. Previous studies indicated a role of cis-Golgi plant golgins (long coiled-coil domains proteins anchored to Golgi membranes) in Golgi biogenesis. Here we show a tethering role for the golgin AtCASP at the ER-Golgi interface. Using live-cell imaging, Golgi body dynamics were compared in Arabidopsis thaliana leaf epidermal cells expressing fluorescently tagged AtCASP, a truncated AtCASP-ΔCC lacking the coiled-coil domains, and the Golgi marker STtmd. Golgi body speed and displacement were significantly reduced in AtCASP-ΔCC lines. Using a dual-colour optical trapping system and a TIRF-tweezer system, individual Golgi bodies were captured in planta. Golgi bodies in AtCASP-ΔCC lines were easier to trap, and the ER-Golgi connection was more easily disrupted. Occasionally, the ER tubule followed a trapped Golgi body with a gap, indicating the presence of other tethering factors. Our work confirms that the intimate ER-Golgi association can be disrupted or weakened by expression of truncated AtCASP-ΔCC, and suggests that this connection is most likely maintained by a golgin-mediated tethering complex.HighlightHere we show that the Golgi-associated Arabidopsis thaliana protein AtCASP may form part of a golgin-mediated tethering complex involved in anchoring plant Golgi stacks to the endoplasmic reticulum (ER).


2019 ◽  
Vol 60 (9) ◽  
pp. 2113-2126 ◽  
Author(s):  
Ayan Sadhukhan ◽  
Takuo Enomoto ◽  
Yuriko Kobayashi ◽  
Toshihiro Watanabe ◽  
Satoshi Iuchi ◽  
...  

Abstract The transcription factor sensitive to proton rhizotoxicity 1 (STOP1) regulates multiple stress tolerances. In this study, we confirmed its involvement in NaCl and drought tolerance. The root growth of the T-DNA insertion mutant of STOP1 (stop1) was sensitive to NaCl-containing solidified MS media. Transcriptome analysis of stop1 under NaCl stress revealed that STOP1 regulates several genes related to salt tolerance, including CIPK23. Among all available homozygous T-DNA insertion mutants of the genes suppressed in stop1, only cipk23 showed a NaCl-sensitive root growth phenotype comparable to stop1. The CIPK23 promoter had a functional STOP1-binding site, suggesting a strong CIPK23 suppression led to NaCl sensitivity of stop1. This possibility was supported by in planta complementation of CIPK23 in the stop1 background, which rescued the short root phenotype under NaCl. Both stop1 and cipk23 exhibited a drought tolerant phenotype and increased abscisic acid-regulated stomatal closure, while the complementation of CIPK23 in stop1 reversed these traits. Our findings uncover additional pleiotropic roles of STOP1 mediated by CIPK23, which regulates various ion transporters including those regulating K+-homeostasis, which may induce a trade-off between drought tolerance and other traits.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Elisa Dell’Aglio ◽  
Ivan Dalvit ◽  
Sylvain Loubéry ◽  
Teresa B. Fitzpatrick

Abstract Background PDX1.2 has recently been shown to be a regulator of vitamin B6 biosynthesis in plants and is implicated in biotic and abiotic stress resistance. PDX1.2 expression is strongly and rapidly induced by heat stress. Interestingly, PDX1.2 is restricted to eudicota, wherein it behaves as a non-catalytic pseudoenzyme and is suggested to provide an adaptive advantage to this clade. A first report on an Arabidopsis insertion mutant claims that PDX1.2 is indispensable for viability, being essential for embryogenesis. However, a later study using an independent insertion allele suggests that knockout mutants of pdx1.2 are viable. Therefore, the essentiality of PDX1.2 for Arabidopsis viability is a matter of debate. Given the important implications of PDX1.2 in stress responses, it is imperative to clarify if it is essential for plant viability. Results We have studied the previously reported insertion alleles of PDX1.2, one of which is claimed to be essential for embryogenesis (pdx1.2–1), whereas the other is viable (pdx1.2–2). Our study shows that pdx1.2–1 carries multiple T-DNA insertions, but the T-DNA insertion in PDX1.2 is not responsible for the loss of embryogenesis. By contrast, the pdx1.2–2 allele is an overexpressor of PDX1.2 under standard growth conditions and not a null allele as previously reported. Nonetheless, upregulation of PDX1.2 expression under heat stress is impaired in this mutant line. In wild type Arabidopsis, studies of PDX1.2-YFP fusion proteins show that the protein is enhanced under heat stress conditions. To clarify if PDX1.2 is essential for Arabidopsis viability, we generated several independent mutant lines using the CRISPR-Cas9 gene editing technology. All of these lines are viable and behave similar to wild type under standard growth conditions. Reciprocal crosses of a subset of the CRISPR lines with pdx1.2–1 recovers viability of the latter line and demonstrates that knocking out the functionality of PDX1.2 does not impair embryogenesis. Conclusions Gene editing reveals that PDX1.2 is dispensable for Arabidopsis viability and resolves conflicting reports in the literature on its function.


Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1875-1887
Author(s):  
Nicole Bechtold ◽  
Bénédicte Jaudeau ◽  
Sylvie Jolivet ◽  
Bruno Maba ◽  
Daniel Vezon ◽  
...  

Abstract In planta transformation methods are now commonly used to transform Arabidopsis thaliana by Agrobacterium tumefaciens. The origin of transformants obtained by these methods has been studied by inoculating different floral stages and examining gametophytic expression of an introduced β-glucuronidase marker gene encoding GUS. We observed that transformation can still occur after treating flowers where embryo sacs have reached the stage of the third division. No GUS expression was observed in embryo sacs or pollen of plants infiltrated with an Agrobacterium strain bearing a GUS gene under the control of a gametophyte-specific promoter. To identify the genetic target we used an insertion mutant in which a gene essential for male gametophytic development has been disrupted by a T-DNA bearing a Basta resistance gene (BR). In this mutant the BR marker is transferred to the progeny only by the female gametes. This mutant was retransformed with a hygromycin resistance marker and doubly resistant plants were selected. The study of 193 progeny of these transformants revealed 25 plants in which the two resistance markers were linked in coupling and only one plant where they were linked in repulsion. These results point to the chromosome set of the female gametophyte as the main target for the T-DNA.


Author(s):  
Suman Lata ◽  
Anshul Watts ◽  
S. R. Bhat

In Arabidopsis, most of the genes encoding mitochondrial ribosomal proteins are located in the nucleus and only seven are present in the mitochondrial genome. Assembly of a functional ribosome requires coordinated expression of ribosomal protein encoding genes located in both these organelles. Genes and promoters of nuclear encoded mitochondrial ribosomal protein coding genes of plants have not been well characterized so far. In the present study we have characterized Arabidopsis thaliana SALK mutant lines with T-DNA insertion in Rps14 or Rps19 gene. The location of T-DNA insertion in the mutant lines was confirmed and plants homozygous and hemizygous for TDNA insertion were identified for both Rps14 and Rps19 genes. In homozygous T-DNA mutant lines of both Rps14 and Rps19 genes, the expression was estimated using RTPCR. Rps14 and Rps19 transcripts similar to wild type were present in homozygous mutant plants of Rps14 and Rps19 which indicated that T-DNA insertion has not affected their expression.


1994 ◽  
Vol 5 (4) ◽  
pp. 551-558 ◽  
Author(s):  
Seok So Chang ◽  
Soon Ki Park ◽  
Byung Chul Kim ◽  
Bong Joong Kang ◽  
Dal Ung Kim ◽  
...  

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