RESUMO
MAIN CONCLUSION: The overexpression of RXam1 leads to a reduction in bacterial growth of XamCIO136, suggesting that RXam1 might be implicated in strain-specific resistance. Cassava bacterial blight (CBB) caused by Xanthomonas axonopodis pv. manihotis (Xam) is a prevalent disease in all regions, where cassava is cultivated. CBB is a foliar and vascular disease usually controlled through host resistance. Previous studies have found QTLs explaining resistance to several Xam strains. Interestingly, one QTL called XM5 that explained 13% of resistance to XamCIO136 was associated with a similar fragment of the rice Xa21-resistance gene called PCR250. In this study, we aimed to further identify and characterize this fragment and its role in resistance to CBB. Screening and hybridization of a BAC library using the molecular marker PCR250 as a probe led to the identification of a receptor-like kinase similar to Xa21 and were called RXam1 (Resistance to Xam 1). Here, we report the functional characterization of susceptible cassava plants overexpressing RXam1. Our results indicated that the overexpression of RXam1 leads to a reduction in bacterial growth of XamCIO136. This suggests that RXAM1 might be implicated in strain-specific resistance to XamCIO136.
Assuntos
Resistência à Doença/genética , Manihot/genética , Doenças das Plantas/microbiologia , Xanthomonas axonopodis , Receptores de Ativinas/genética , Receptores de Ativinas/metabolismo , Genes de Plantas/genética , Imunidade Vegetal/genética , Reação em Cadeia da Polimerase , Locos de Características Quantitativas/genéticaRESUMO
Taeniids exhibit a great adaptive plasticity, which facilitates their establishment, growth, and reproduction in a hostile inflammatory microenvironment. Transforming Growth Factor-ß (TGFß), a highly pleiotropic cytokine, plays a critical role in vertebrate morphogenesis, cell differentiation, reproduction, and immune suppression. TGFß is secreted by host cells in sites lodging parasites. The role of TGFß in the outcome of T. solium and T. crassiceps cysticercosis is herein explored. Homologues of the TGFß family receptors (TsRI and TsRII) and several members of the TGFß downstream signal transduction pathway were found in T. solium genome, and the expression of Type-I and -II TGFß receptors was confirmed by RT-PCR. Antibodies against TGFß family receptors recognized cysticercal proteins of the expected molecular weight as determined by Western blot, and different structures in the parasite external tegument. In vitro, TGFß promoted the growth and reproduction of T. crassiceps cysticerci and the survival of T. solium cysticerci. High TGFß levels were found in cerebrospinal fluid from untreated neurocysticercotic patients who eventually failed to respond to the treatment (P = 0.03) pointing to the involvement of TGFß in parasite survival. These results indicate the relevance of TGFß in the infection outcome by promoting cysticercus growth and treatment resistance.
Assuntos
Cysticercus/imunologia , Interações Hospedeiro-Parasita/imunologia , Neurocisticercose/imunologia , Taenia solium/imunologia , Fator de Crescimento Transformador beta/imunologia , Receptores de Ativinas/genética , Receptores de Ativinas/imunologia , Receptores de Ativinas/metabolismo , Animais , Antígenos de Helmintos/genética , Antígenos de Helmintos/imunologia , Antígenos de Helmintos/metabolismo , Antiparasitários/farmacologia , Antiparasitários/uso terapêutico , Cysticercus/genética , Cysticercus/metabolismo , Modelos Animais de Doenças , Resistência a Medicamentos/imunologia , Genoma Helmíntico/imunologia , Proteínas de Helminto/genética , Proteínas de Helminto/imunologia , Proteínas de Helminto/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Neurocisticercose/líquido cefalorraquidiano , Neurocisticercose/tratamento farmacológico , Neurocisticercose/parasitologia , Transdução de Sinais/imunologia , Suínos , Taenia solium/genética , Taenia solium/metabolismo , Fator de Crescimento Transformador beta/líquido cefalorraquidiano , Fator de Crescimento Transformador beta/metabolismoRESUMO
Mammary gland morphogenesis and differentiation are mediated through the combined activities of systemic hormones and locally synthesized growth factors. Activin, a member of the transforming growth factor (TGF)-beta superfamily, is known to regulate the growth and differentiation of several cell types. In the present study, we investigated the role of activin in rat mammary gland on different stages of development. We found that activin A in vitro inhibits the proliferation of isolated acini, and this effect increases with the development of the gland. This factor also produces in vitro an inhibition of the final differentiation of acini obtained from 19th day pregnant rats. We also report the expression of activin receptors IIA and IIB mRNA in whole rat mammary gland and acini, with decreased levels of expression of type IIA (in both compartments) and IIB (in acini) during pregnancy and lactogenesis. In addition, we show that activin betaB-subunit mRNA decreases throughout pregnancy, and that the mRNA levels of follistatin (Fst) (its ligand protein) are high in cycling rats and at the beginning of pregnancy and diminish thereafter, having the acini higher levels of expression. Our data show that activin betaB-subunit, follistatin and ActRIIA and IIB transcripts are expressed in rat mammary gland at appropriate times and locations during development, allowing an interplay that might regulate activin action on growth and differentiation of the gland.