12 research outputs found
A defective ABC transporter of the MRP family, responsible for the bean lpa1 mutation, affects the regulation of the phytic acid pathway, reduces seed myo-inositol and alters ABA sensitivity
We previously identified the lpa1 (low phytic acid) 280-10 line that carries a mutation conferring a 90% reduction in phytic acid (InsP6) content. In contrast to other lpa mutants, lpa1(280-10) does not display negative pleiotropic effects. In the present paper, we have identified the mutated gene and analysed its impact on the phytic acid pathway. Here, we mapped the lpa1(280-10) mutation by bulk analysis on a segregating F2 population, an then, by comparison with the soybean genome, we identified and sequenced a candidate gene. The InsP6 pathway was analysed by gene expression and quantification of metabolites. The mutated Pvmrp1(280-10) cosegregates with the lpa1(280-10) mutation, and the expression level of several genes of the InsP6 pathway are reduced in the lpa1(280-10) mutant as well as the inositol and raffinosaccharide content. PvMrp2, a very similar paralogue of PvMrp1 was also mapped and sequenced. The lpa1 mutation in beans is likely the result of a defective Mrp1 gene (orthologous to the lpa genes AtMRP5 and ZmMRP4), while its Mrp2 paralog is not able to complement the mutant phenotype in the seed. This mutation appears to down-regulate the InsP6 pathway at the transcriptional level, as well as altering inositol-related metabolism and affecting ABA sensitivity
The Arabidopsis Malectin-Like/LRR-RLK IOS1 is Critical for BAK1-Dependent and BAK1-Independent Pattern-Triggered Immunity
Plasma membrane-localized pattern recognition receptors (PRRs) such as FLAGELLIN SENSING2 (FLS2), EF-TU RECEPTOR (EFR) and CHITIN ELICITOR RECEPTOR KINASE 1 (CERK1) recognize microbe-associated molecular patterns (MAMPs) to activate pattern-triggered immunity (PTI). A reverse genetics approach on genes responsive to the priming agent beta-aminobutyric acid (BABA) revealed IMPAIRED OOMYCETE SUSCEPTIBILITY1 (IOS1) as a critical PTI player. Arabidopsis thaliana ios1 mutants were hyper-susceptible to Pseudomonas syringae bacteria. Accordingly, ios1 mutants showed defective PTI responses, notably delayed up-regulation of the PTI-marker gene FLG22-INDUCED RECEPTOR-LIKE KINASE1 (FRK1), reduced callose deposition and mitogen-activated protein kinase activation upon MAMP treatment. Moreover, Arabidopsis lines over-expressing IOS1 were more resistant to bacteria and showed a primed PTI response. In vitro pull-down, bimolecular fluorescence complementation, co-immunoprecipitation, and mass spectrometry analyses supported the existence of complexes between the membrane-localized IOS1 and BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1)-dependent PRRs FLS2 and EFR, as well as with the BAK1-independent PRR CERK1. IOS1 also associated with BAK1 in a ligand-independent manner, and positively regulated FLS2-BAK1 complex formation upon MAMP treatment. In addition, IOS1 was critical for chitin-mediated PTI. Finally, ios1 mutants were defective in BABA-induced resistance and priming. This work reveals IOS1 as a novel regulatory protein of FLS2-, EFR- and CERK1-mediated signaling pathways that primes PTI activation
QUES, a new Phaseolus vulgaris genotype resistant to common bean weevils, contains the Arcelin-8 allele coding for new lectin-related variants
In common bean (Phaseolus vulgaris L.), the most abundant seed proteins are the storage protein phaseolin and the family of closely related APA proteins (arcelin, phytohemagglutinin and α-amylase inhibitor). High variation in APA protein composition has been described and the presence of arcelin (Arc) has been associated with bean resistance against two bruchid beetles, the bean weevil (Acanthoscelides obtectus Say) and the Mexican bean weevil (Zabrotes subfasciatus Bohemian). So far, seven Arc variants have been identified, all in wild accessions, however, only those containing Arc-4 were reported to be resistant to both species. Although many efforts have been made, a successful breeding of this genetic trait into cultivated genotypes has not yet been achieved. Here, we describe a newly collected wild accession (named QUES) and demonstrate its resistance to both A. obtectus and Z. subfasciatus. Immunological and proteomic analyses of QUES seed protein composition indicated the presence of new Arc and arcelin-like (ARL) polypeptides of about 30 and 27 kDa, respectively. Sequencing of cDNAs coding for QUES APA proteins confirmed that this accession contains new APA variants, here referred to as Arc-8 and ARL-8. Moreover, bioinformatic analysis showed the two proteins are closely related to APA components present in the G12949 wild bean accession, which contains the Arc-4 variant. The presence of these new APA components, combined with the observations that they are poorly digested and remain very abundant in A. obtectus feces, so-called frass, suggest that the QUES APA locus is involved in the bruchid resistance. Moreover, molecular analysis indicated a lower complexity of the locus compared to that of G12949, suggesting that QUES should be considered a valuable source of resistance for further breeding purposes
The low phytic acid1-241 (lpa1-241) maize mutation altersthe accumulation of anthocyanin pigment in the kernel
The lpa1 mutations in maize are caused by
lesions in the ZmMRP4 (multidrug resistance-associated
proteins 4) gene. In previous studies, several mutations have been isolated in this locus causing a reduction of phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, or InsP6) content and an
equivalent increasing of free phosphate. In particular, the
lpa1-241 mutation causes a reduction of up to 90% of
phytic acid, associated with strong pleiotropic effects on
the whole plant. In this work, we show, for the first time to
our knowledge, an interaction between the accumulation of
anthocyanin pigments in the kernel and the lpa mutations.
In fact the lpa1-241 mutant accumulates a higher level of
anthocyanins as compared to wild type either in the embryo
(about 3.8-fold) or in the aleurone layer (about 0.3-fold) in
a genotype able to accumulate anthocyanin. Furthermore,
we demonstrate that these pigments are mislocalised in
the cytoplasm, conferring a blue pigmentation of the
scutellum, because of the neutral/basic pH of this cellular
compartment. As a matter of fact, the propionate treatment,
causing a specific acidification of the cytoplasm, restored
the red pigmentation of the scutellum in the mutant and
expression analysis showed a reduction of ZmMRP3
anthocyanins’ transporter gene expression. On the whole,
these data strongly suggest a possible interaction between
the lpa mutation and anthocyanin accumulation and compartmentalisation in the kernel
Actinide–lanthanide co-extraction by rigidified diglycolamides
<p>Within the actinide and lanthanide co-extraction strategy, three rigidified diglycolamides, namely 2,6-bis (<i>N</i>-dodecyl-carboxamide)-4-oxo-4<i>H</i>-pyran (<b>1</b>), 2,6-bis-[<i>N</i>-(4-<i>tert</i>-butylphenyl)carboxamide]-4-oxo-4<i>H</i>-pyran (<b>2</b>), 2,6-bis[(<i>N</i>-docecyl-<i>N</i>-methyl)carboxamide]-4-methoxy-tetrahydro-pyran (<b>3</b>), were synthesized. Moreover, the effect of structural rigidification on Am(III) and Eu(III) extraction under different conditions was investigated. The carboxamide extractant <b>3</b> resembles the extracting behavior of <i>N,N,N</i>′,<i>N</i>′‐tetraoctyl diglycolamide (TODGA) in terms of efficiency and affinity within the lanthanide family, together with fast kinetics and satisfactory cation back-extraction. The presence of 1-octanol in the diluent mixture strongly affects the ligand stability. Moreover, despite the low extraction efficiency showed by <b>1</b> and <b>2</b>, all the three ligands exhibit a higher affinity for Am with respect to TODGA, resulting in a lower lanthanide/Americium separation factor, of around 4 for ligand <b>3</b> and close to 1 for ligands <b>1</b> and <b>2</b>.</p
Identification ofN,1,4,4-Tetramethyl-8-{[4-(4-methylpiperazin-1-yl)phenyl]amino}-4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline-3-carboxamide (PHA-848125), a Potent, Orally Available Cyclin Dependent Kinase Inhibitor
The discovery of a novel class of inhibitors of cyclin dependent kinases (CDKs) is described. Starting from compound 1, showing good potency as inhibitor of CDKs but being poorly selective against a panel of serine−threonine and tyrosine kinases, new analogues were synthesized. Enhancement in selectivity, antiproliferative activity against A2780 human ovarian carcinoma cells, and optimization of the physical properties and pharmacokinetic profile led to the identification of highly potent and orally available compounds. Compound 28 (PHA-848125), which in the preclinical xenograft A2780 human ovarian carcinoma model showed good efficacy and was well tolerated upon repeated daily treatments, was identified as a drug candidate for further development. Compound 28 is currently undergoing phase I and phase II clinical trials