Identifying how genes and their functions evolve after duplication is central to understanding gene family radiation. In this study, we systematically examined the functional diversification of the glutathione S-transferase (GST) gene family in Populus trichocarpa by integrating phylogeny, expression, substrate specificity, and enzyme kinetic data. GSTs are ubiquitous proteins in plants that play important roles in stress tolerance and detoxification metabolism. Genome annotation identified 81 GST genes in Populus that were divided into eight classes with distinct divergence in their evolutionary rate, gene structure, expression responses to abiotic stressors, and enzymatic properties of encoded proteins. In addition, when all the functional parameters were examined, clear divergence was observed within tandem clusters and between paralogous gene pairs, suggesting that subfunctionalization has taken place among duplicate genes. The two domains of GST proteins appear to have evolved under differential selective pressures. The C-terminal domain seems to have been subject to more relaxed functional constraints or divergent directional selection, which may have allowed rapid changes in substrate specificity, affinity, and activity, while maintaining the primary function of the enzyme. Our findings shed light on mechanisms that facilitate the retention of duplicate genes, which can result in a large gene family with a broad substrate spectrum and a wide range of reactivity toward different substrates.

BackgroundPreeclampsia (PE) is an obstetric disorder with high morbidity and mortality rates but without clear pathogeny. The dysfunction of the blood coagulation-fibrinolysis system is a salient characteristic of PE that varies in severity, and necessitates different treatments. Therefore, it is necessary to find suitable predictors for the onset and severity of PE.ObjectivesWe aimed to evaluate blood coagulation parameters and platelet indices as potential predictors for the onset and severity of PE.MethodsBlood samples from 3 groups of subjects, normal pregnant women (n = 79), mild preeclampsia (mPE) (n = 53) and severe preeclampsia (sPE) (n = 42), were collected during early and late pregnancy. The levels of coagulative parameters and platelet indices were measured and compared among the groups. The receiver-operating characteristic (ROC) curves of these indices were generated, and the area under the curve (AUC) was calculated. The predictive values of the selected potential parameters were examined in binary regression analysis.ResultsDuring late pregnancy in the normal pregnancy group, the activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and platelet count decreased, while the fibrinogen level and mean platelet volume (MPV) increased compared to early pregnancy (p<0.05). However, the PE patients presented with increased APTT, TT, MPV and D-dimer (DD) during the third trimester. In the analysis of subjects with and without PE, TT showed the largest AUC (0.743) and high predictive value. In PE patients with different severities, MPV showed the largest AUC (0.671) and ideal predictive efficiency.ConclusionNormal pregnancy causes a maternal physiological hypercoagulable state in late pregnancy. PE may trigger complex disorders in the endogenous coagulative pathways and consume platelets and FIB, subsequently activating thrombopoiesis and fibrinolysis. Thrombin time and MPV may serve as early monitoring markers for the onset and severity of PE, respectively.

Brassicales plants produce glucosinolates and myrosinases that generate toxic isothiocyanates conferring broad resistance against pathogens and herbivorous insects. Nevertheless, some cosmopolitan fungal pathogens, such as the necrotrophic white mold Sclerotinia sclerotiorum, are able to infect many plant hosts including glucosinolate producers. Here, we show that S. sclerotiorum infection activates the glucosinolate-myrosinase system, and isothiocyanates contribute to resistance against this fungus. S. sclerotiorum metabolizes isothiocyanates via two independent pathways: conjugation to glutathione and, more effectively, hydrolysis to amines. The latter pathway features an isothiocyanate hydrolase that is homologous to a previously characterized bacterial enzyme, and converts isothiocyanate into products that are not toxic to the fungus. The isothiocyanate hydrolase promotes fungal growth in the presence of the toxins, and contributes to the virulence of S. sclerotiorum on glucosinolate-producing plants.

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