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

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

Development of nano-immunosensor with magnetic separation and electrical detection of Escherichia coli using antibody conjugated Fe3O4@Ppy

Detection of bacterial pathogens is the need of the hour due to the increase in antibiotic resistance and the infusion of multi-drug-resistant parasites. The conventional strategies such as ELISA, PCR, and MNP based tests for the detection are efficient but they are cost, time, lab, and manpower intensive. Thus, warranting a simple and effective technique for rapid detection of bacterial pathogens. Magnetic nanoparticles (NPs) have proved to be better alternatives for separation of bacterial pathogens from a variety of sample sources. However, the use of magnetic NPs has not been successful in the detection of these parasites. The current work involves the coating of magnetic NPs (Fe3O4) with a conducting polymer (polypyrrole; Ppy) to facilitate simultaneous separation and detection. Electrical (conductivity) measurement was the mode of choice due to the sensitivity, accuracy, and ease it offers. To enhance the conductivity, carboxylic groups were expressed on the Fe3O4@Ppy complex and to ensure specificity, E. coli specific antibodies were conjugated. The resulting complex at various process parameters was characterized using FTIR, VSM, and SEM. SEM images were recorded to ensure bacterial separation at optimal process parameters. The impedance analysis and conductivity measurements were carried out for the sample volume of 15 μl. The bacterial suspension from 101 –106 CFU ml−1 was successfully detected with a limit of detection of 10 CFU ml−1 within 10 min using a simplistic detection method.Dr D Bodas and Dr V Gajbhiye acknowledge funding received from ICMR-New Delhi to carry out this work (ICMR Grant No. 5/3/8/12/2019-ITR).Peer reviewe