The total protein contents of rice seeds are significantly higher in the three wild rice species (Oryza rufipogon Grill., Oryza officinalis Wall. and Oryza meyeriana Baill.) than in the cultivated rice (Oryza sativa L.). However, there is still no report regarding a systematic proteomic analysis of seed proteins in the wild rice species. Also, the relationship between the contents of seed total proteins and rice nutritional quality has not been thoroughly investigated. The total seed protein contents, especially the glutelin contents, of the three wild rice species were higher than those of the two cultivated rice materials. Based on the protein banding patterns of SDS-PAGE, O. rufipogon was similar to the two cultivated rice materials, followed by O. officinalis, while O. meyeriana exhibited notable differences. Interestingly, O. meyeriana had high contents of glutelin and low contents of prolamine, and lacked 26 kDa globulin band and appeared a new 28 kDa protein band. However, for O. officinali a 16 kDa protein band was absent and a row of unique 32 kDa proteins appeared. In addition, we found that 13 kDa prolamine band disappeared while special 14 kDa and 12 kDa protein bands were present in O. officinalis. Two-dimensional gel electrophoresis (2-DE) analysis revealed remarkable differences in protein profiles of the wild rice species and the two cultivated rice materials. Also, the numbers of detected protein spots of the three wild rice species were significantly higher than those of two cultivated rice. A total of 35 differential protein spots were found for glutelin acidic subunits, glutelin precursors and glutelin basic subunits in wild rice species. Among those, 18 protein spots were specific and 17 major spots were elevated. Six differential protein spots for glutelin acidic subunits were identified, including a glutelin type-A 2 precursor and five hypothetical proteins. This was the first report on proteomic analysis of the three wild rice species. Overall results suggest that there were many new types of glutelin subunits and precursor in the three wild rice species. Hence, wild rice species are important genetic resources for improving nutritional quality to rice.

Aspergillus oryzaeis widely used in industrial applications, which always encounter changes within multiple environmental conditions during fermentation, such as temperature stress. However, the molecular mechanisms by whichA.oryzaeprotects against temperature stress have not been elucidated. Therefore, this study aimed to characterize the fermentative behavior, transcriptomic profiles, and metabolic changes ofA.oryzaein response to temperature stress. Both low and high temperatures inhibited mycelial growth and conidial formation ofA.oryzae. Transcriptomic analysis revealed that most differentially expressed genes (DEGs) were involved in sugar metabolism and lipid metabolism under temperature stress. Specifically, the DEGs in trehalose synthesis and starch metabolism were upregulated under low-temperature stress, while high temperatures inhibited the expression of genes involved in fructose, galactose, and glucose metabolism. Quantitative analysis of intracellular sugar further revealed that low temperature increased trehalose accumulation, while high temperature increased the contents of intracellular trehalose, galactose, and glucose, consistent with transcriptome analysis. In addition, most DEGs involved in lipid metabolism were significantly downregulated under low-temperature stress. Furthermore, the metabolomic analysis revealed that linoleic acid, triacylglycerol, phosphatidylethanolamine, and phosphoribosyl were significantly decreased in response to low-temperature stress. These results increase our understanding of the coping mechanisms ofA.oryzaein response to temperature stress, which lays the foundation for future improvements through genetic modification to enhanceA.oryzaeagainst extreme temperature stress.

GATA transcription factors (TFs) are involved in the regulation of growth processes and various environmental stresses. Although GATA TFs involved in abiotic stress in plants and some fungi have been analyzed, information regarding GATA TFs in Aspergillusoryzae is extremely poor. In this study, we identified and functionally characterized seven GATA proteins from A.oryzae 3.042 genome, including a novel AoSnf5 GATA TF with 20-residue between the Cys-X₂-Cys motifs which was found in Aspergillus GATA TFs for the first time. Phylogenetic analysis indicated that these seven A. oryzae GATA TFs could be classified into six subgroups. Analysis of conserved motifs demonstrated that Aspergillus GATA TFs with similar motif compositions clustered in one subgroup, suggesting that they might possess similar genetic functions, further confirming the accuracy of the phylogenetic relationship. Furthermore, the expression patterns of seven A.oryzae GATA TFs under temperature and salt stresses indicated that A. oryzae GATA TFs were mainly responsive to high temperature and high salt stress. The protein–protein interaction network of A.oryzae GATA TFs revealed certain potentially interacting proteins. The comprehensive analysis of A. oryzae GATA TFs will be beneficial for understanding their biological function and evolutionary features and provide an important starting point to further understand the role of GATA TFs in the regulation of distinct environmental conditions in A.oryzae.

Background: Bacterial blight (BB) caused byXanthomonas oryzaePv.oryzae(Xoo) is one of the most serious diseases of rice worldwide.Oryza officinalisWall ex Watt, harboring abundant genetic diversity and disease resistance features, are important resources of exploring resistance genes with broad-spectrum resistance to BB. However, the molecular mechanisms and genes of BB resistance inO. officinalishave been rarely explored.Results: Here, the BB resistance of four different originO. officinalispopulations in Yunnan were identified by seven representative hypervirulentXooraces, which exhibited different BB resistance among four populations, in which the BB resistance of the Gengma_Lincang population was the strongest. In addition, the pathogenetic ability of sevenXooraces toO. officinaliswas different in that the pathogenicity of PXO99 was stronger than that of C5. There were no remarkable differences in leaf microstructures among fourO. officinalispopulations, revealing the differences in resistance of fourO. officinalisto BB are caused by the endogenous resistance genes. Furthermore, our results proved that there were no nine cloned BB resistance genes in four populations but possessed dominantXa5, dominantXa13, and recessivexa3/xa26homologous alleles ofxa5,xa13, andXa3/Xa26resistance genes. These three homologous genes were isolated and cloned from four populations and namedOoXa5,OoXa13, andOoxa3/xa26. The expression profile revealed that the expression levels ofOoXa13andOoxa3/xa26were significantly down-regulated under PXO99 and C5 stress, especially in the Gengma_Lincang population, suggesting theO. officinalismight enhance BB resistance by down-regulating the expression level ofOoXa13andOoxa3/xa26.Conclusion: The BB resistance genes ofO. officinalishad its own characteristics by expression pattern and BLAST analysis ofOoXa5,OoXa13, andOoxa3/xa26, which indicated that there might be new genes or molecular mechanism of BB resistance inO. officinalis.Our studies provided a solid foundation and reference for revealing the molecular mechanism of BB resistance inO. officinalis.

Filamentous fungi hold critical industrial value for their ability to produce enzymes, antibiotics, organic acids, and food fermentation. GATA transcription factors (TFs) serve as central regulators of nitrogen metabolism, synthesis of secondary metabolites, stress adaptation, and directly influence fungal development and pathogenicity in filamentous fungi. In this review, we primarily discuss the structural characterization, different types, and phylogenetic analysis of filamentous fungi GATA TFs in filamentous fungi. Subsequently, we systematically summarize the multifunctions of GATA TFs in the mycelial growth, morphological differentiation, and conidial development of filamentous fungi. In addition, we explore their functions in the synthesis of secondary metabolites such as antibiotics (e.g., cephalosporins, penicillins) and organic acids (e.g., ganoderic acid, fumaric acid) in filamentous fungi. Furthermore, we focus on the key roles of GATA TFs AreA and AreB in nitrogen and carbon metabolism in filamentous fungi and their potential synergistic regulatory relationships. Finally, we review the important roles of GATA TFs in the adaptation of filamentous fungi to environmental changes. This review provides research ideas for the development of genetically engineered strains with optimized growth characteristics, increased target metabolites in the fermentation production process, and enhanced environmental adaptability.