Identification, characterization, and expression analysis of auxin response factor (ARF) gene family in Brachypodium distachyon.

Auxin response factors (ARFs) are one type of essential family of transcription factors that bind with auxin response elements (AuxRE), and play vital roles in variety of plant development and physiological processes. Brachypodium distachyon, related to the major cereal grain species, were recently developed to be a good model organism for functional genomics research. So far, genome-wide overview of the ARF gene family in B. distachyon was not available. Here, a systemic analysis of ARF gene family members in B. distachyon was performed. A comprehensive overview of the characterization of the BdARFs was obtained by multiple bioinformatics analyses, including the gene and protein structure, chromosome locations, conserved motifs of proteins, phylogenetic analysis, and cis-elements in promoters of BdARF. Results showed that all BdARFs contained conserved DBD, MR, and CTD could be divided into four classes, Ia, IIa, IIb, and III. Expression profiles of BdARF genes indicated that they were expressed across various tissues and organs, which could be clustered into three main expression groups, and most of BdARF genes were involved in phytohormone signal transduction pathways and regulated physiological process in responding to multiple environmental stresses. And predicted regulatory network between B. distachyon ARFs and IAAs was also discussed. Our genomics analysis of BdARFs could yield new insights into the complexity of the control of BdARF genes and lead to potential applications in the investigation of the accurate regulatory mechanisms of ARFs in herbaceous plants.

Immunomodulatory effect of ganoderma lucidum polysaccharides (GLP) on long-term heavy-load exercising mice.

Long-term heavy-load exercise can lead to a decrease in the organism's immune response. In this study, we used 100 Kunming (KM) mice to investigate the immune-regulatory effects of Ganoderma lucidum polysaccharides (GLP) on long-term heavy-load exercising mice. Peripheral white blood cells (WBC), the absolute value of neutrophils (NEUT), the phagocytic function of macrophages, serum agglutination valence, and the number of plaque-forming cells (PFC) were evaluated 4 weeks after gavaging long-term heavy-load exercising mice with GLP. After exercise, the WBC count in peripheral blood, absolute neutrophil count, macrophage phagocytic index, serum agglutination valence, and the number of plaque-forming cells were significantly reduced in the mice not fed GLP. Both medium and high doses of GLP drastically increased peripheral WBC, absolute neutrophil count, macrophage phagocytic index, serum agglutination valence, and the number of plaque-forming cells in long-term heavy-load exercising mice. High doses of GLP increased peritoneal macrophage phagocytic rate considerably. With this study, we demonstrate that 4 weeks of heavy-load exercise can lead to exercise-induced immunosuppression in mice. A supplement of GLP fed to these mice improves both non-specific and specific immune responses among these mice. The effect for the high-dose GLP treatment is especially significant.

Genome-wide survey of heat shock factors and heat shock protein 70s and their regulatory network under abiotic stresses in Brachypodium distachyon.

The heat shock protein 70s (Hsp70s) and heat shock factors (Hsfs) play key roles in protecting plant cells or tissues from various abiotic stresses. Brachypodium distachyon, recently developed an excellent model organism for functional genomics research, is related to the major cereal grain species. Although B. distachyon genome has been fully sequenced, the information of Hsf and Hsp70 genes and especially the regulatory network between Hsfs and Hsp70s remains incomplete. Here, a total of 24 BdHsfs and 29 BdHsp70s were identified in the genome by bioinformatics analysis and the regulatory network between Hsfs and Hsp70s were performed in this study. Based on highly conserved domain and motif analysis, BdHsfs were grouped into three classes, and BdHsp70s divided into six groups, respectively. Most of Hsf proteins contain five conserved domains: DBD, HR-A/B region, NLS and NES motifs and AHA domain, while Hsp70 proteins have three conserved domains: N-terminal nucleotide binding domain, peptide binding domain and a variable C-terminal lid region. Expression data revealed a large number of BdHsfs and BdHsp70s were induced by HS challenge, and a previous heat acclimation could induce the acquired thermotolerance to help seedling suffer the severe HS challenge, suggesting that the BdHsfs and BdHsp70s played a role in alleviating the damage by HS. The comparison revealed that, most BdHsfs and BdHsp70s genes responded to multiple abiotic stresses in an overlapping relationship, while some of them were stress specific response genes. Moreover, co-expression relationships and predicted protein-protein interaction network implied that class A and B Hsfs played as activator and repressors, respectively, suggesting that BdHsp70s might be regulated by both the activation and the repression mechanisms under stress condition. Our genomics analysis of BdHsfs and BdHsp70s provides important evolutionary and functional characterization for further investigation of the accurate regulatory mechanisms among Hsfs and Hsp70s in herbaceous plants.