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Fruit rot caused by Colletotrichum magnum is a crucial watermelon disease threatening the production and quality. To understand the pathogenic mechanism of C. magnum, we optimized the Agrobacterium tumefaciens-mediated transformation system (ATMT) for genetic transformation of C. magnum. The transformation efficiency of ATMT was an average of around 245 transformants per 100 million conidia. Southern blot analysis indicated that approximately 75% of the mutants contained a single copy of T-DNA. Pathogenicity test revealed that three mutants completely lost pathogenicity. The T-DNA integration sites (TISs) of three mutants were Identified. In mutant Cm699, the TISs were found in the intron region of the gene, which encoded a protein containing AP-2 complex subunit s, and simultaneous gene deletions were observed. Two deleted genes encoded the transcription initiation protein SPT3 and a hypothetical protein, respectively. In mutant Cm854, the TISs were found in the 5'-flanking regions of a gene that was similar to the MYO5 encoding Myosin I of Pyricularia oryzae (78%). In mutant Cm1078, the T-DNA was integrated into the exon regions of two adjacent genes. One was 5'-3' exoribonuclease 1 encoding gene while the other encoded a WD-repeat protein retinoblastoma binding protein 4, the homolog of the MSl1 of Saccharomyces cerevisiae. [ABSTRACT FROM AUTHOR]

Satellites image segmentation is useful in a variety of fields. Professionals in related industries can gain a lot of important information by segmenting satellite images, but processing them is difficult due to the complex background and various locations of interest. The simplest basic picture segmentation approach is multilevel threshold segmentation, but the results can be unsatisfactory due to its computational complexity and high computation time. This paper presents an improved bald eagle search algorithm based on the standard bald eagle search algorithm. This method is used to find the best threshold values for the Renyi entropy multilevel threshold methods. To expand the diversity of the bald eagle population and the bald eagle's prey space, the strategy uses Chaotic Tent and Levy Fight method. The method is utilized to do multilevel segmentation of color satellite images, and the results suggest that it is capable of doing so. At the same time, this method has fewer iterations and can achieve better threshold values than typical methods such as standard bald eagle search optimization algorithm. [ABSTRACT FROM AUTHOR]

Rice false smut caused by Ustilaginoidea virens is a serious disease of rice (Oryza sativa), severely reducing plant mass and yields worldwide. We performed genome-wide analysis of the CCHC-type zinc-finger transcription factor family in this pathogen. We identified and functionally characterized seven UvCCHC genes in U. virens. The deletion of various UvCCHC genes affected the stress responses, vegetative growth, conidiation, and virulence of U. virens. DUvCCHC5 mutants infected rice spikelets normally but could not form smut balls. Sugar utilization experiments showed that the DUvCCHC5 mutants were defective in the utilization of glucose, sucrose, lactose, stachyose, and trehalose. Deletion of UvCCHC5 did not affect the expression of rice genes associated with grain filling, as revealed by RT-qPCR. We propose that the DUvCCHC5 mutants are impaired in transmembrane transport, and the resulting nutrient deficiencies prevent them from using nutrients from rice to form smut balls. RNA-seq data analysis indicated that UvCCHC4 affects the expression of genes involved in mitochondrial biogenesis, ribosomes, transporters, and ribosome biogenesis. These findings improve our understanding of the molecular mechanism underlying smut ball formation in rice by U. virens. [ABSTRACT FROM AUTHOR]

Polycomb repressive complex 2 (PRC2) is responsible for the trimethylation of lysine 27 of histone H3 (H3K27me3)-mediated transcriptional silencing. At present, its biological roles in the devastating rice pathogenic fungus Ustilaginoidea virens remain unclear. In this study, we analyzed the function of a putative PRC2 catalytic subunit UvKmt6. The results showed that disruption of UvKMT6 resulted in reduced growth, conidiation and pathogenicity in U. virens. Furthermore, UvKmt6 is essential for establishment of H3K27me3 modification, which covers 321 genes in the genome. Deletion of UvKMT6 led to transcriptional derepression of 629 genes, 140 of which were occupied with H3K27me3 modification. Consistent with RNA-seq and ChIP-seq analysis, UvKmt6 was further confirmed to participate in the transcriptional repression of genes encoding effectors and genes associated with secondary metabolites production, such as PKSs, NRPSs and Cytochrome P450s. Notably, we found that UvKmt6 is involved in transcriptional repression of oxidative, osmotic, cell wall and nutrient starvation stresses response-related genes. From the perspective of gene expression and phenotype, in addition to the relatively conservative role in fungal development, virulence and production of secondary metabolites, we further reported that UvKmt6-mdediated H3K27me3 plays a critical role in the response to various stresses in U. virens. [ABSTRACT FROM AUTHOR]

Ustilaginoidea virens, causing rice false smut (RFS) is an economically important ascomycetous fungal pathogen distributed in rice-growing regions worldwide. Here, we identified a novel transcription factor UvCGBP1 (Cutinase G-box binding protein) from this fungus, which is unique to ascomycetes. Deletion of UvCGBP1 affected development and virulence of U. virens. A total of 865 downstream target genes of UvCGBP1 was identified using ChIP-seq and the most significant KEGG enriched functional pathway was the MAPK signaling pathway. Approximately 36% of target genes contain the AGGGG (G-box) motif in their promoter. Among the targets, deletion of UvCGBP1 affected transcriptional and translational levels of UvPmk1 and UvSlt2, both of which were important in virulence. ChIP-qPCR, yeast one-hybrid and EMSA confirmed that UvCGBP1 can bind the promoter of UvPmk1 or UvSlt2. Overexpression of UvPmk1 in the AUvCGBP1-33 mutant restored partially its virulence and hyphae growth, indicating that UvCGBP1 could function via the MAPK pathway to regulate fungal virulence. Taken together, this study uncovered a novel regulatory mechanism of fungal virulence linking the MAPK pathway mediated by a G-box binding transcription factor, UvCGBP1. [ABSTRACT FROM AUTHOR]