Metabolic and proteomic analysis of nitrogen metabolism mechanisms involved in the sugarcane - Fusarium verticillioides interaction.

Pokkah boeng disease (PBD) is a foliar disease causing severe losses in sugarcane crop production. Research into resistance mechanisms against the causal agent, Fusarium verticillioides, is particularly important for farmers and researchers. This work based on the comprehensive analysis of metabolic, proteomic, and bioinformatics data on nitrogen (N) metabolism, which revealed that this biosynthetic reactions was closely related to resistance mechanisms in the sugarcane- F. verticillioides interaction. Our results suggested that pathogen infection reduced the suppression of nitrate reductase (NR) activity, reducing ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) assimilation, which reduces glutamine synthetase (GS), glutamate synthetase (GOGAT) activity and polynucleotide synthesis and promotes RNA degradation, resulting in a decrease in ribosome levels and protein synthesis. Cysteine was found to be associated with the symptoms of PBD, while alanine, lysine, proline, and glutamic acid were found to be involved in protective and regulatory mechanisms as well. Additionally, glutamate played an important role in sugarcane defense against pathogens through the biosynthesis of proline and polyamines. Cyanamide, glutamate, proline, tyrosine, and arachidonic acid metabolism actively participate in resistance and response to stress. C5XPZ6 and C5XCA6 were considered to be critical proteins and key effectors according to this study. In conclusion, we have identified potential proteins and pathways involved in sugarcane resistance to F. verticillioides, revealing new findings that may be useful in the design of future diagnostics or sugarcane protection strategies and providing new insights into the molecular mechanisms of sugarcane-pathogen interactions.

Comparative analysis of sugarcane root transcriptome in response to the plant growth-promoting Burkholderia anthina MYSP113.

The diazotrophic Burkholderia anthina MYSP113 is a vital plant growth-promoting bacteria and sugarcane root association. The present study based on a detailed analysis of sugarcane root transcriptome by using the HiSeq-Illumina platform in response to the strain MYSP113. The bacterium was initially isolated from the rhizosphere of sugarcane. To better understand biological, cellular, and molecular mechanisms, a de novo transcriptomic assembly of sugarcane root was performed. HiSeq-Illumina platformwas employed for the sequencing of an overall of 16 libraries at a 2×100 bp configuration. Differentially expressed genes (DEGs) analysis identified altered gene expression in 370 genes (total of 199 up-regulated genes and 171 down-regulated genes). Deciphering the huge datasets, concerning the functioning and production of biological systems, a high throughput genome sequencing analysis was attempted with Gene ontology functional analyses and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The report revealed a total of 148930 unigenes. 70414 (47.28%) of them were annotated successfully to Gene Ontology (GO) terms. 774 at 45 days, 4985 of 30 days and 15 days of 6846 terms were significantly regulated. GO analysis revealed that many genes involved in the metabolic, oxidation-reduction process and biological regulatory processes in response to strain MYSP113 and significantly enriched as compare to the control. Moreover, KEGG enriched results show that differentially expressed genes were classified into different pathway categories involved in various processes, such as nitrogen metabolism, plant hormone signal transduction, etc. The sample correlation analyses could help examine the similarity at the gene expression level. The reliability of the observed differential gene expression patterns was validated with quantitative real-time PCR (qRT-PCR). Additionally, plant enzymes activities such as peroxidase and superoxide dismutase were significantly increased in plant roots after the inoculation of strain MYSP113. The results of the research may help in understanding the plant growth-promoting rhizobacteria and plant interaction.

Molecular Characterization and Co-expression Analysis of the SnRK2 Gene Family in Sugarcane (Saccharum officinarum L.).

In plants, both abscisic acid (ABA) dependent and independent pathways form the basis for the response to environmental stresses. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) plays a central role in plant stress signal transduction. However, complete annotation and specific expression patterns of SnRK2s in sugarcane remain unclear. For the present study, we performed a full-length cDNA library survey of sugarcane, thus identifying ten SoSnRK2 genes via phylogenetic, local BLAST methods, and various bioinformatics analyses. Phylogenetic analysis indicated division of SoSnRK2 genes into three subgroups, similar to other plant species. Gene structure comparison with Arabidopsis suggested a unique evolutionary imprint of the SnRK2 gene family in sugarcane. Both sequence alignment and structural annotation provided an overview of the conserved N-terminal and variations of the C-terminal, suggesting functional divergence. Transcript and transient expression assays revealed SoSnRK2s to be involved in the responses to diverse stress signals, and strong ABA induction of SoSnRK2s in subgroup III. Co-expression network analyses indicated the existence of both conserved and variable biological functions among different SoSnRK2s members. In summary, this comprehensive analysis will facilitate further studies of the SoSnRK2 family and provide useful information for the functional validation of SoSnRK2s.