Project description:Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defense and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. In this context, this study aimed at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of root gene expression of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon roots) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition.
Project description:Cooperation involving Plant Growth-Promoting Rhizobacteria results in improvements of plant growth and health. While pathogenic and symbiotic interactions are known to induce transcriptional changes for genes related to plant defense and development, little is known about the impact of phytostimulating rhizobacteria on plant gene expression. In this context, this study aimed at identifying genes significantly regulated in rice roots upon Azospirillum inoculation, considering possible favored interaction between a strain and its original host cultivar. Genome-wide analyses of root gene expression of Oryza sativa japonica cultivars Cigalon and Nipponbare were performed, by using microarrays, seven days post inoculation with A. lipoferum 4B (isolated from Cigalon roots) or Azospirillum sp. B510 (isolated from Nipponbare) and compared to the respective non-inoculated condition. For each of the four condition, three replicates were analysed on an oligo microarray produced by NimbleGenTM (Madison, WI, USA). The microarray was derived of the one previously described in Yuan et al. 2005 . This microarray is composed of about 385,000 60mer probes selected for their GC content, Tm and number of cycles needed to synthesize the oligo. This chip contains 90,000 probes representing 45,000 genes (two probes per gene) of rice Oryza sativa ssp. japonica, based on the TIGR rice genome annotation version 3.1 genes (Chaparro et al. 2007) and 201 691 oligomers corresponding to previously described copies of LTR retrotranposons available on the retrOryza database (www.retroryza.fr). Probes represent 1,000 bp of the LTR-retrotransposon flanking regions at the 3M-bM-^@M-^Y and 5M-bM-^@M-^Y side. The oligonucleotides have been designed at the 3M-bM-^@M-^Y end of the genes to detect the readings of reverse transcriptase. On the other hand, the LTR-retrotransposons are represented throughout their length at the rate of a probe every 500 bp.
Project description:Purpose: Transcriptional profiling of Oryza sativa japonica Nipponbare roots after one, three and seven days post inoculation with Azoarcus olearius BH72 (vs. non-inoculated controls) to understand the changes in transcriptomic response of rice roots to colonization by bacterial endophyte at initial stages of interaction; Additional set-up was included in which bacterial growth was boosted (through increasing 20-times carbon source - malic acid in the plant's hydroponic medium) to study rice roots transcriptome during enhanced colonization by the endophyte after three days post inoculation. Methods: Rice root mRNA profiles after one day, three days (including additional set-ups for boosted colonization), and seven days post inoculation with Azoarcus olearius BH72 and corresponding non-inoculated controls were generated by RNA sequencing, in triplicates, using Illumina NextSeq 500. Raw reads were then filtered, trimmed (PHRED > 33) and mapped onto IRGSP-1 version of Oryza sativa ssp. japonica cv. Nipponbare genome using CLC Genomics Workbench 8.5.1 (Qiagen, Germany). Expression of 17 selected genes was confirmed via RT-qPCR. Results: Using the RNA-Seq technology we obtained transcriptomic data from 24 sequencing libraries, with an average 46,181,160 clean reads per library, of which 87% or more were mapped onto the Oryza sativa ssp. japonica cv. Nipponbare IRGSP-1.0 genome (Fig. S3). We considered genes as differentially regulated (DEG) that exhibited at least 1.5-fold-change in expression level between Azo-colonized and non-colonized roots and FDR<0.05. Conclusions: Bacteria appeared to short-circuit the initial root defense responses for a compatible interaction during endophytic establishment, involving previously unknown putative rice candidate genes.
Project description:In order to understand the salt response-mechanisms and ability of plant growth promoting bacteria to moderate harmful effect of salt, two Canola cultivars, salt-tolerant Hyola308, and salt-sensitive Sarigol, were treated with Inoculation with plant growth promoting bacteria, Pseudomonas fluorescens, and salt. For this quantitative proteomics technique was used.
Project description:Root exudates play an important role in plant-microbe interaction. The transcriptional profilings of plant growth-promoting rhizobacteria Bacillus amyloliquefaciens SQR9 in response to maize root exudates under static condition, were investigated by an Illumina RNA-seq for understanding the regulatory roles of the root exudates. 4 treatments, including 2 blank control (24 h and 48 h-post inoculation, named as 5 and 15, respectively), and 2 treatments with maize root exudates (24 h and 48 h-post inoculation, named as 7 and 17, respectively)
Project description:Herbaspirillum seropedicae is an endophytic bacterium that can fix nitrogen and promote a hormonal imbalance that leads to a plant growth-promoting effect when used as a microbial inoculant. Studies focused on mechanisms of action are crucial for a better understanding of the bacteria-plant interaction and optimization of plant growth-promoting response. The work aims to understand the underlined mechanisms responsible for the early stimulatory growth effects of the H. seropedicae inoculation in maize. To perform it, we combined transcriptomic and proteomic approaches with physiological analysis. The results obtained with the inoculation showed increased root biomass (233 and 253%) and shoot biomass (249 and 264%), respectively, for the fresh and dry mass of maize seedlings and increased green content and development. Omics data analysis for the positive biostimulation phenotype revealed that inoculation increases N-uptake and N-assimilation machinery through differential expressed nitrate transporters and amino acids pathway, as well carbon/nitrogen metabolism integration by the tricarboxylic acid cycle and the polyamines pathway. Additionally, phytohormone levels of root and shoot tissues increased in bacterium-inoculated-maize plants leading to feedback regulation by the ubiquitin-proteasome system. The early biostimulatory effect of H. seropedicae partially results from hormonal imbalance coupled with efficient nutrient uptake-assimilation and a boost in primary anabolic metabolism of carbon-nitrogen integrative pathways.
Project description:Possitive effects of plant growth promoting bacteria (PGPB) inoculation on plant growth and development are dependent on interaction between bacterial strains and plant roots, which are usually the bacterial niche. Furthermore, phytohormones are key regulators of plant physiology. Ethylene is essential in plant growth and development and in response to drought. Plant sensibility to ethylene is involved in plant response to PGPB strain inoculation and plant growth promotion. We used microarrays to detail the global programme of gene expression underlying plant interaction with two different PGPB strains (isolated from arid soils in southern Spain) regarding to plant sentitivity to ethylene by tomato ethylene receptor 3 (SlETR3).
Project description:affy_meloidogyne_rice - affy_meloidogyne_rice - Plant-parasitic nematodes cause profound economic losses to global agriculture with the obligate sedentary endoparasitic varieties; amongst them the cyst and Root Knot Nematode (RKN) species are the most damaging. Meloidogyne graminicola is a RKN mainly found in the monocotyledous plants. In the compatible interaction with Oryza sativa, M. graminicola induces the characteristic formation of hook-like galls resulting from the redifferentiation of root cells into multinucleate giant cells. In order to understand the global transcriptome changes occurring during infection, several recent microarray studies on root knots have demonstrated complex changes in host plant gene expression in response to infection. However, to our knowledge, all these transcriptome studies were performed on dicotyledous plants. A histological study enabled us to observe hyperplasia and hypertrophy of the surrounding cells leading to the formation of hook-like galls. We also investigated the plant response to M. graminicola by carrying out a global analysis of gene expression during gall formation in rice, using giant cell-enriched root tissues at an early stage (2dpi) and a latter stage (4dpi) of gall development.-Oryza sativa (var. Nipponbare) seedlings were grown on 6 cm3 SAP substrate completed with diluted Hoaglands solution (Reversat et al., 1999). Culture units were placed in a growth chamber illuminated with fluorescent tubes 9/24 h and maintained at 23°C for 5 days before being inoculated with a 100 J2-stage juveniles M. graminicola. One day after inoculation (dai), the rice seedlings were immersed in de-ionised water to remove all J2s that had not penetrated the roots and allowing synchronization of the infection. Each seedling was transferred to a hydroponic mini chamber (Reversat et al., 2004). Sampling was performed at 2 and 4 dai and each of them contained galls from 70 infected plants, they were then hand-dissected, frozen in liquid-nitrogen and stored at -80°C. As reference samples, uninfected meristematic root fragments were dissected from seedlings grown under the same conditions. Each sample was replicated 3 times. Keywords: normal vs disease comparison,time course 9 arrays - rice