title: Trichoderma asperellum(T42) andPseudomonas fluorescens(OKC)-Enhances Resistance of Pea againstErysiphe pisithrough Enhanced ROS Generation and Lignifications.
abstract: Plant signaling mechanisms are not completely understood in plant-fungal biotrophic pathogen interactions. Further how such interactions are influenced by compatible rhizosphere microbes are also not well-studied. Therefore, we explored the pea-Erysiphe pisi(obligate biotroph) system to understand the interaction and applied compatible rhizospheric bio-agentsTrichoderma asperellum(T42) andPseudomonas fluorescens(OKC) singly or in combination to assess their influence on the host while under the pathogen challenge. Transcript accumulation pattern of some vital genes in the lignin biosynthetic pathway in pea underE. pisichallenge indicated enhanced activation of the pathway. Interestingly, transcript accumulations were even higher in the bio-agent treated plants compared to untreated plants after pathogen inoculation particularly in co-inoculated treatments. Further, down regulation of the lignifications-associated ABC transporter gene in the pathogen challenged plants possibly is an indication of passive diffusion of monolignols across the membrane from symplast. Additionally, up regulation of NADPH oxidase gene revealed ROS generation in the challenged plants which was confirmed through spectrophotometric estimation of H2O2. Up regulation of laccase and peroxidase along with higher H2O2generation points out their involvement in lignifications which was further confirmed through cross section analysis of pea stems that showed increased lignifications in pathogen challenged plants co-inoculated with the bioagents. Interestingly, pathogen responsive MAPK homologs MAPK3/MAPK6 and the enzyme serine threonine kinase that activates MAPKs were down regulated and the results possibly indicate non-participation of the MAPK cascade in this interaction. Therefore, it can be concluded that the microbial treatments enhanced pea resistance toE. pisiby generation of ROS and lignifications.
authors.affiliation: Department of Botany, Banaras Hindu University Varanasi, India.
authors.forename: Jai S
authors.initials: JS
authors.lastname: Patel
authors.affiliation: Department of Botany, Banaras Hindu University Varanasi, India.
authors.forename: Ravindra N
authors.initials: RN
authors.lastname: Kharwar
authors.affiliation: Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University Varanasi, India.
authors.forename: Harikesh B
authors.initials: HB
authors.lastname: Singh
authors.affiliation: Department of Botany, Banaras Hindu University Varanasi, India.
authors.forename: Ram S
authors.initials: RS
authors.lastname: Upadhyay
authors.affiliation: Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University Varanasi, India.
authors.forename: Birinchi K
authors.initials: BK
authors.lastname: Sarma
keywords: ABC transporter; MAP kinase; NADHP oxidase; monolignol; pea; powdery mildew