RESUMEN
Banana Fusarium wilt (BFW), which is one of the most important banana diseases worldwide, is mainly caused by Fusarium oxysporum f. sp. cubense tropic race 4 (Foc TR4). In this study, we conducted secretome analysis of Foc R1 and Foc TR4 and discovered a total of 120 and 109 secretory proteins (SPs) from Foc R1 cultured alone or with banana roots, respectively, and 129 and 105 SPs respectively from Foc TR4 cultured under the same conditions. Foc R1 and Foc TR4 shared numerous SPs associated with hydrolase activity, oxidoreductase activity, and transferase activity. Furthermore, in culture with banana roots, Foc R1 and Foc TR4 secreted many novel SPs, of which approximately 90% (Foc R1; 57/66; Foc TR4; 50/55) were unconventional SPs without signal peptides. Comparative analysis of SPs in Foc R1 and Foc TR4 revealed that Foc TR4 not only generated more specific SPs but also had a higher proportion of SPs involved in various metabolic pathways, such as phenylalanine metabolism and cysteine and methionine metabolism. The cysteine biosynthesis enzyme O-acetylhomoserine (thiol)-lyase (OASTL) was the most abundant root inducible Foc TR4-specific SP. In addition, knockout of the OASTL gene did not affect growth of Foc TR4; but resulted in the loss of pathogenicity in banana 'Brazil'. We speculated that OASTL functions in banana by interfering with the biosynthesis of cysteine, which is the precursor of an enormous number of sulfur-containing defense compounds. Overall, our studies provide a basic understanding of the SPs in Foc R1 and Foc TR4; including a novel effector in Foc TR4.
Asunto(s)
Liasas de Carbono-Oxígeno , Fusarium/patogenicidad , Musa/microbiología , Proteoma/metabolismo , Liasas de Carbono-Oxígeno/genética , Liasas de Carbono-Oxígeno/aislamiento & purificación , Liasas de Carbono-Oxígeno/metabolismo , Fusarium/química , Fusarium/genética , Fusarium/metabolismo , Perfilación de la Expresión Génica , Regulación Fúngica de la Expresión Génica , Organismos Modificados Genéticamente , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Raíces de Plantas/microbiología , Proteoma/análisis , Proteoma/genética , Vías Secretoras/genética , Transcriptoma , Virulencia/fisiología , Factores de Virulencia/genética , Factores de Virulencia/aislamiento & purificación , Factores de Virulencia/metabolismoRESUMEN
New gene origination is a major source of genomic innovations that confer phenotypic changes and biological diversity. Generation of new mitochondrial genes in plants may cause cytoplasmic male sterility (CMS), which can promote outcrossing and increase fitness. However, how mitochondrial genes originate and evolve in structure and function remains unclear. The rice Wild Abortive type of CMS is conferred by the mitochondrial gene WA352c (previously named WA352) and has been widely exploited in hybrid rice breeding. Here, we reconstruct the evolutionary trajectory of WA352c by the identification and analyses of 11 mitochondrial genomic recombinant structures related to WA352c in wild and cultivated rice. We deduce that these structures arose through multiple rearrangements among conserved mitochondrial sequences in the mitochondrial genome of the wild rice Oryza rufipogon, coupled with substoichiometric shifting and sequence variation. We identify two expressed but nonfunctional protogenes among these structures, and show that they could evolve into functional CMS genes via sequence variations that could relieve the self-inhibitory potential of the proteins. These sequence changes would endow the proteins the ability to interact with the nucleus-encoded mitochondrial protein COX11, resulting in premature programmed cell death in the anther tapetum and male sterility. Furthermore, we show that the sequences that encode the COX11-interaction domains in these WA352c-related genes have experienced purifying selection during evolution. We propose a model for the formation and evolution of new CMS genes via a "multi-recombination/protogene formation/functionalization" mechanism involving gradual variations in the structure, sequence, copy number, and function.
Asunto(s)
Citoplasma/genética , Evolución Molecular , Genes de Plantas , Genoma Mitocondrial , Infertilidad Vegetal/genética , Secuencia de Aminoácidos , Secuencia de Bases , Variaciones en el Número de Copia de ADN/genética , Regulación de la Expresión Génica de las Plantas , Estudios de Asociación Genética , Variación Genética , Modelos Genéticos , Oryza/genética , Proteínas de Plantas/química , Proteínas de Plantas/genética , Recombinación Genética/genética , Selección GenéticaRESUMEN
PREMISE OF THE STUDY: We developed microsatellite primers and tested the polymorphism of seven populations of Solanum rostratum distributed throughout their range in China. These will be useful for biologists to study the mating systems and genetic diversity and differentiation of S. rostratum in its native range in Mexico and in its current distribution throughout the world. METHODS AND RESULTS: Five polymorphic microsatellites were identified for Solanum rostratum. The number of alleles per locus ranged from 1 to 8 (average = 4) for 195 individuals examined from seven populations. The observed and expected heterozygosities ranged from 0.000 to 1.000 and 0.000 to 0.778, respectively. CONCLUSIONS: These five markers can be used in studies examining population genetics and the mating system of Solanum rostratum to investigate its invasive mechanisms and to provide information for developing management strategies for this species.
