Botryosphaeriaceae are an important fungal family that cause woody plant diseases worldwide. Recent studies have established a correlation between environmental factors and disease expression; however, less is known about factors that trigger these diseases. The current study reports on the 43.3 Mb de novo genome of Lasiodiplodia theobromae and five other genomes of Botryosphaeriaceae pathogens. Botryosphaeriaceous genomes showed an expansion of gene families associated with cell wall degradation, nutrient uptake, secondary metabolism and membrane transport, which contribute to adaptations for wood degradation. Transcriptome analysis revealed that genes involved in carbohydrate catabolism, pectin, starch and sucrose metabolism, and pentose and glucuronate interconversion pathways were induced during infection. Furthermore, genes in carbohydrate-binding modules, lysine motif domain and the glycosyl hydrolase gene families were induced by high temperature. Among these genes, overexpression of two selected putative lignocellulase genes led to increased virulence in the transformants. These results demonstrate the importance of high temperatures in opportunistic infections. This study also presents a set of Botryosphaeriaceae-specific effectors responsible for the identification of virulence-related pathogen-associated molecular patterns and demonstrates their active participation in suppressing hypersensitive responses. Together, these findings significantly expand our understanding of the determinants of pathogenicity or virulence in Botryosphaeriaceae and provide new insights for developing management strategies against them.

Rationale: Epidemiologic studies have identified an associate between iron deficiency (ID) and the use of oral contraceptives (CC) and ischemic stroke (IS). To date, however, the underlying mechanism remains poorly understood. Both ID and CC have been demonstrated to up-regulate the level and iron-binding ability of transferrin, with our recent study showing that this up-regulation can induce hypercoagulability by potentiating FXIIa/thrombin and blocking antithrombin-coagulation proteases interactions. Objective: To investigate whether transferrin mediates IS associated with ID or CC and the underlying mechanisms. Methods and Results: Transferrin levels were assayed in the plasma of IS patients with a history of iron-deficiency anemia (IDA), IDA patients, venous thromboembolism patients using CC, and ID mice, and in the cerebrospinal fluid of some IS patients. Effects of ID and estrogen administration on transferrin expression and coagulability and the underlying mechanisms were studied in vivo and in vitro. High levels of transferrin and transferrin-thrombin/FXIIa complexes were found in patients and ID mice. Both ID and estrogen up-regulated transferrin through hypoxia and estrogen response elements located in the transferrin gene enhancer and promoter regions, respectively. In addition, ID, administration of exogenous transferrin or estrogen, and transferrin overexpression promoted platelet-based thrombin generation and hypercoagulability, and thus aggravated IS. In contrast, anti-transferrin antibodies, transferrin knockdown, and peptide inhibitors of transferrin-thrombin/FXIIa interaction exerted anti-IS effects in vivo. Conclusions: Our findings revealed that certain factors (i.e., ID and CC) up-regulating transferrin are risk factors of thromboembolic diseases decipher a previously unrecognized mechanistic association among ID, CC and IS and provide a novel strategy for the development of anti-IS medicine by interfering with transferrin-thrombin/FXIIa interactions.

Coagulation balance is maintained through fine-tuned interactions among clotting factors, whose physiological concentrations vary substantially. In particular, the concentrations of coagulation proteases (pM to nM) are much lower than their natural inactivator antithrombin (AT,~3 μM), suggesting the existence of other coordinators. In the current study, we found that transferrin (normal plasma concentration~40 μM) interacts with fibrinogen, thrombin, factor XIIa (FXIIa), and AT with different affinity to maintain coagulation balance. Normally, transferrin is sequestered by binding with fibrinogen (normal plasma concentration~10 μM) at a molar ratio of 4:1. In atherosclerosis, abnormally up-regulated transferrin interacts with and potentiates thrombin/FXIIa and blocks AT's inactivation effect on coagulation proteases by binding to AT, thus inducing hypercoagulability. In the mouse model, transferrin overexpression aggravated atherosclerosis, whereas transferrin inhibition via shRNA knockdown or treatment with antitransferrin antibody or designed peptides interfering with transferrin-thrombin/FXIIa interactions alleviated atherosclerosis. Collectively, these findings identify that transferrin is an important clotting regulator and an adjuster in the maintenance of coagulation balance and modifies the coagulation cascade.