ZmSnRK2.8 responds to ABA through the SnRK2-PP2C complex

Understanding the responses of maize to abscisic acid (ABA) dependent drought tolerance is an important topic for the biotechnological application of functional mechanisms of stress adaptation. Key components that control and modulate stress adaptive pathways include SnRK2 (sucrose non-fermenting 1-related protein kinases 2) proteins. Recent studies indicate that SnRK2 are plant specific kinases that together with ABA ligand PYR/PYL/RCAR proteins and type 2C group A protein phosphatases constitute the central core of abscisic acid perception and signal transduction. Here, we study drought responses in maize by analyzing the mechanism of ZmSnRK2.8 in ABA signaling to establish relevant analogies with other plant species. ZmSnRK2.8 is a very closely related protein to Arabidopsis OST1 (open stomata 1) kinase with nuclear and cytosolic subcellular localization able to auto-phosphorylate S182 or T183 amino acids on its activation loop suggesting that phosphorylation at these sites may be a general mechanism for SnRK2 activation. In addition, ZmSnRK2.8 is activated by ABA and interacts with PP2C phosphatases in a constitutive, ABA independent manner. Together, our data suggest a conserved mechanism of plant responses to ABA and drought stress in maize and point to the potential use of this kinase in improving programs of drought tolerance in crops

Enhancing Localized Pesticide Action through Plant Foliage by Silver-Cellulose Hybrid Patches

Efficacy and efficiency of pesticide application in the field through the foliage still face many challenges. There exists a mismatch between the hydrophobic character of the leaf and the active molecule, low dispersion of the pesticides on the leaves' surface, runoff loss, and rolling down of the active molecules to the field, decreasing their efficacy and increasing their accumulation to the soil. We produced bacterial cellulose-silver nanoparticles (BC-AgNPs) hybrid patches by in situ thermal reduction under microwave irradiation in a scalable manner and obtaining AgNPs strongly anchored to the BC. Those hybrids increase the interaction of the pesticide (AgNPs) with the foliage and avoids runoff loss and rolling down of the nanoparticles. The positive antibacterial and antifungal properties were assessed in vitro against the bacteria Escherichia coli and two agro-economically relevant pathogens: the bacterium Pseudomonas syringae and the fungus Botrytis cinerea. We showed in vivo inhibition of the infection in Nicotiana benthamiana and tomato leaves, as proven by the suppression of the expression of defense molecular markers and reactive oxygen species production. The hydrogel-like character of the bacterial cellulose matrix increases the adherence to the foliage of the patches

Engineering estructural defense responses in tomato for resistance against the bacterial wilt

Trabajo presentado en 5th International Symposium on Plant Apoplastic Diffusion Barriers (PADiBA) celebrado en Dundee (Escocia) del 13 al 15 de septiembre de 2022

Safety and Efficacy of Crizotinib in Combination with Temozolomide and Radiotherapy in Patients with Newly Diagnosed Glioblastoma: Phase Ib GEINO 1402 Trial

Simple Summary Most patients with glioblastoma, the most frequent primary brain tumor in adults, develop resistance to standard first-line treatment combining temozolomide and radiotherapy. Signaling through the hepatocyte growth factor receptor (c-MET) and the midkine (ALK ligand) promotes gliomagenesis and glioma stem cell maintenance, contributing to the resistance of glioma cells to anticancer therapies. This trial reports for the first time that the addition of crizotinib, an ALK, ROS1, and c-MET inhibitor, to standard RT and TMZ is safe and resulted in a promising efficacy for newly diagnosed patients with glioblastoma. Background: MET-signaling and midkine (ALK ligand) promote glioma cell maintenance and resistance against anticancer therapies. ALK and c-MET inhibition with crizotinib have a preclinical therapeutic rationale to be tested in newly diagnosed GBM. Methods: Eligible patients received crizotinib with standard radiotherapy (RT)/temozolomide (TMZ) followed by maintenance with crizotinib. The primary objective was to determine the recommended phase 2 dose (RP2D) in a 3 + 3 dose escalation (DE) strategy and safety evaluation in the expansion cohort (EC). Secondary objectives included progression-free (PFS) and overall survival (OS) and exploratory biomarker analysis. Results: The study enrolled 38 patients. The median age was 52 years (33-76), 44% were male, 44% were MGMT methylated, and three patients had IDH1/2 mutation. In DE, DLTs were reported in 1/6 in the second cohort (250 mg/QD), declaring 250 mg/QD of crizotinib as the RP2D for the EC. In the EC, 9/25 patients (32%) presented grade >= 3 adverse events. The median follow up was 18.7 months (m) and the median PFS was 10.7 m (95% CI, 7.7-13.8), with a 6 m PFS and 12 m PFS of 71.5% and 38.8%, respectively. At the time of this analysis, 1 died without progression and 24 had progressed. The median OS was 22.6 m (95% CI, 14.1-31.1) with a 24 m OS of 44.5%. Molecular biomarkers showed no correlation with efficacy. Conclusions: The addition of crizotinib to standard RT and TMZ for newly diagnosed GBM was safe and the efficacy was encouraging, warranting prospective validation in an adequately powered, randomized controlled study

Induced ligno-suberin vascular coating and tyramine-derived hydroxycinnamic acid amides restrict Ralstonia solanacearum colonization in resistant tomato

19 páginas.- 9 figuras.- referenciasTomato varieties resistant to the bacterial wilt pathogen Ralstonia solanacearum have the ability to restrict bacterial movement in the plant. Inducible vascular cell wall reinforcements seem to play a key role in confining R. solanacearum into the xylem vasculature of resistant tomato. However, the type of compounds involved in such vascular physico-chemical barriers remain understudied, while being a key component of resistance. Here we use a combination of histological and live-imaging techniques, together with spectroscopy and gene expression analysis to understand the nature of R. solanacearum-induced formation of vascular coatings in resistant tomato. We describe that resistant tomato specifically responds to infection by assembling a vascular structural barrier formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties, effectively contributing to resistance.Research is funded by MCIN/AEI/10.13039/501100011033 (NSC, MV), MCIN/AEI/PID2019-110330GB-C21 (MF, OS), MCIN/AEI/PID2020-118968RBI00 (JR), through the ‘Severo Ochoa Programme for Centres of Excellence in R&D’ (SEV-2015-0533, CEX2019-000917 and CEX2019-000902-S funded by MCIN/AEI/ 10.13039/501100011033), and by the Spanish National Research Council (CISC) pie-201620E081 (JR, AG) and the Generalitat de Catalunya (2017SGR765 grant). AK is the recipient of a Netaji Subhas – Indian Council of Agricultural Research International Fellowship. SS acknowledges financial support from DOC-FAM, European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 754397. This work was also supported by the CERCA Program/Generalitat de Catalunya.Peer reviewe

Enhanced water stress tolerance of transgenic maize plants over-expressing LEA Rab28 gene

Late Embryogenesis Abundant (LEA) proteins participate in plant stress responses and contribute to the acquisition of desiccation tolerance. In this report Rab28 LEA gene has been over-expressed in maize plants under a constitutive maize promoter. The expression of Rab28 transcripts led to the accumulation and stability of Rab28 protein in the transgenic plants. Native Rab28 protein is localized to nucleoli in wild type maize embryo cells; here we find by whole-mount immunocytochemistry that in root cells of Rab28 transgenic and wild-type plants the protein is also associated to nucleolar structures. Transgenic plants were tested for stress tolerance and resulted in sustained growth under polyethyleneglycol (PEG)-mediated dehydration compared to wild-type controls. Under osmotic stress transgenic seedlings showed increased leaf and root areas, higher relative water content (RWC), reduced chlorophyll loss and lower Malondialdehyde (MDA) production in relation to wild-type plants. Moreover, transgenic seeds exhibited higher germination rates than wild-type seeds under water deficit. Overall, our results highlight the presence of transgenic Rab28 protein in nucleolar structures and point to the potential of group 5 LEA Rab28 gene as candidate to enhance stress tolerance in maize plants.This work was supported by Ministerio de Ciencia e Innovación MICINN (Spain) [grant Bio 2009-13044-CO2-01] and Agencia Española de Cooperación Internacional para el Desarrollo (AECID) [grant A, 025042,09]. Imen Amara was financed by the Agència de Gestió d’Ajust Universitaris i de Recerca (AGUR) predoctoral Fellowship [FI-DRG 2011FI, B2, 00124].Peer reviewe

MAPK phosphatase MKP2 mediates disease responses in Arabidopsis and functionally interacts with MPK3 and MPK6

Mitogen-activated protein kinase (MAPK) cascades have important functions in plant stress responses and development and are key players in reactive oxygen species (ROS) signalling and in innate immunity. In Arabidopsis, the transmission of ROS and pathogen signalling by MAPKs involves the coordinated activation of MPK6 and MPK3; however, the specificity of their negative regulation by phosphatases is not fully known. Here, we present genetic analyses showing that MAPK phosphatase 2 (MKP2) regulates oxidative stress and pathogen defence responses and functionally interacts with MPK3 and MPK6. We show that plants lacking a functional MKP2 gene exhibit delayed wilting symptoms in response to Ralstonia solanacearum and, by contrast, acceleration of disease progression during Botrytis cinerea infection, suggesting that this phosphatase plays differential functions in biotrophic versus necrotrophic pathogen-induced responses. MKP2 function appears to be linked to MPK3 and MPK6 regulation, as indicated by BiFC experiments showing that MKP2 associates with MPK3 and MPK6 in vivo and that in response to fungal elicitors MKP2 exerts differential affinity versus both kinases. We also found that MKP2 interacts with MPK6 in HR-like responses triggered by fungal elicitors, suggesting that MPK3 and MPK6 are subject to differential regulation by MKP2 in this process. We propose that MKP2 is a key regulator of MPK3 and MPK6 networks controlling both abiotic and specific pathogen responses in plants. © 2010 Blackwell Publishing Ltd.V.L. was financed by the Spanish MCYT (Program Ramon y Cajal) and B.V. by European Union Marie-Curie Early Stage Training Fellowships MEST-CT-2005–020232–2 ADONIS. This work was supported by grants BIO2009–13044 from MCYT (Spain) to MV and BIO2009– 13044 from MCYT (Spain) and CIRIT-2005SGR00276 from Comissionat per Universitats i Recerca de la Generalitat de Catalunya to MP.Peer Reviewe

Gene expression profiles of MON810 and comparable non-GM maize varieties cultured in the field are more similar than are those of conventional lines

Maize is a major food crop and genetically modified (GM) varieties represented 24% of the global production in 2007. Authorized GM organisms have been tested for human and environmental safety. We previously used microarrays to compare the transcriptome profiles of widely used commercial MON810 versus near-isogenic varieties and reported differential expression of a small set of sequences in leaves of in vitro cultured plants of AristisBt/Aristis and PR33P67/PR33P66 (Coll et al. 2008). Here we further assessed the significance of these differential expression patterns in plants grown in a real context, i.e. in the field. Most sequences that were differentially expressed in plants cultured in vitro had the same expression values in MON810 and comparable varieties when grown in the field; and no sequence was found to be differentially regulated in the two variety pairs grown in the field. The differential expression patterns observed between in vitro and field culture were similar between MON810 and comparable varieties, with higher divergence between the two conventional varieties. This further indicates that MON810 and comparable non-GM varieties are equivalent except for the introduced character.This work was financially supported by the Spanish MEC project with ref. AGL2007-65903/AGR. AC received a studentship from the Generalitat de Catalunya (2005FI 00144).Peer reviewe