Comparative Proteomics Analysis of the Rice Roots Colonized byHerbaspirillum seropedicaeStrain SmR1 Reveals Induction of the Methionine Recycling in the Plant Host

Abstract

Although the use of plant growth-promoting bacteria in agriculture is a reality, the molecular basis of plant-bacterial interaction is still poorly understood. We used a proteomic approach to study the mechanisms of interaction of Herbaspirillum seropedicae SmR1 with rice. Root proteins of rice seedlings inoculated or noninoculated with H. seropedicae were separated by 2-D electrophoresis. Differentially expressed proteins were identified by MALDI-TOF/TOF and MASCOT program. Among the identified proteins of H. seropedicae, the dinitrogenase reductase NifH and glutamine synthetase GlnA, which participate in nitrogen fixation and ammonium assimilation, respectively, were the most abundant. The rice proteins up-regulated included the S-adenosylmethionine synthetase, methylthioribose kinase, and acireductone dioxygenase 1, all of which are involved in the methionine recycling. S-Adenosylmethionine synthetase catalyzes the synthesis of S-adenosylmethionine, an intermediate used in transmethylation reactions and in ethylene, polyamine, and phytosiderophore biosynthesis. RT-qPCR analysis also confirmed that the methionine recycling and phytosiderophore biosynthesis genes were up-regulated, while ACC oxidase mRNA level was down-regulated in rice roots colonized by bacteria. In agreement with these results, ethylene production was reduced approximately three-fold in rice roots colonized by H. seropedicae. The results suggest that H. seropedicae stimulates methionine recycling and phytosiderophore synthesis and diminishes ethylene synthesis in rice roots.

Fusarium oxysporum mediates systems metabolic reprogramming of chickpea roots as revealed by a combination of proteomics and metabolomics

“…However, down‐regulation of ACC oxidase by 1.5‐fold in both the cultivars indicated that preferential AdoMet pool was not channelized towards ethylene production. A recent proteomic study has shown that increased expression of AdoMet synthetase and lower level of ACC oxidase resulted in higher methionine recycling and lower ethylene biosynthesis in rice roots against Herbaspirillum seropedicae (Alberton et al ., ). Silencing of AdoHcy hydrolase in transgenic tobacco plants confirmed its role in defence mechanism against pathogens (Masuta et al ., ).…”

RNA-seq transcriptional profiling of Herbaspirillum seropedicae colonizing wheat (Triticum aestivum) roots

“…2a). NifH was among the most abundant protein expressed during interaction of H. seropedicae and rice seedlings (Alberton et al 2013).…”

Essential Genes forIn VitroGrowth of the Endophyte Herbaspirillum seropedicae SmR1 as Revealed by Transposon Insertion Site Sequencing

“…seropedicae with different plant hosts (12–14). In addition, comparative genomics and metagenomics studies have shown that certain functions, e.g., nutrient transport systems, type IV conjugal DNA-protein transfer secretion systems, plant growth promotion genes, and iron uptake systems, are overrepresented in the genomes of bacterial endophytes, compared to rhizospheric or soil bacteria (4, 15–17).…”