The Ustilaginales as Plant Pests and Model Systems

Martínez-Espinoza, Alfredo D.; García-Pedrajas, Maria D.; Gold, Scott E.

doi:10.1006/fgbi.2001.1301

Cited by 131 publications

(93 citation statements)

References 177 publications

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“…Como sería de esperarse, entre los genes identificados se encontró el que codifica la subunidad regulatoria de la PKA. Pero interesantemente, el resto de los genes codificaba los miembros de un módulo MAPK, sugiriendo que mientras la vía PKA está involucrada en el crecimiento levaduriforme, la vía MAPK lo está en el crecimiento micelial (véase revisión de Martínez-Espinoza et al 2002). Posteriormente nosotros demostramos que la adición de AMPc inhibía el crecimiento micelial a pH ácido y que las mutantes afectadas en cualquiera de los genes Ubc eran incapaces de crecer en forma micelial (Martínez-Espinoza et al 2004).…”

Section: Infección En Huéspedes No Naturalesunclassified

Ustilago maydis: ascenso de un hongo mexicano de la gastronomía local al mundo científico

Herrera

2014

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En el presente trabajo se describe la naturaleza del hongo Ustilago maydis, su papel como causante de una enfermedad del maíz, su uso en la cocina mexicana y las condiciones que lo llevaron a convertirse en material de estudio científico, además de algunas características descollantes de su fisiología, genética y bioquímica. U. maydis es un hongo patógeno biotrófico específico del maíz, y el teozintle, siendo el agente causal del “huitlacoche” o carbón común, una enfermedad de distribución mundial que bajo ciertas condiciones puede causar severos daños económicos. Sin embargo, en México, las mazorcas infectadas han sido un alimento usado en la cocina tradicional desde la época pre-colombina, y actualmente también en la alta gastronomía del país y el extranjero. El hongo y sus huéspedes son nativos de la parte central de México, y fueron introducidos en Europa por los españoles, donde la enfermedad fue considerada como una alteración fisiológica de la planta. Su naturaleza como infección fúngica fue reconocida solo hasta la segunda mitad del siglo XIX. U. maydis se introdujo a los laboratorios de investigación a principios del Siglo XX, convirtiéndose en un modelo clásico para el estudio de las bases de la patogénesis fúngica en plantas, de la especificidad en el apareamiento y de la recombinación genética, entre otras. Esto fue debido a su facilidad de manejo, su corto ciclo de vida, y el ser posible su análisis mediante métodos de genética clásica y molecular. El ciclo de vida del hongo es complicado alternando formas de levadura haploide saprofítica y micelio dicariótico infeccioso. Este ciclo sexual solo se completa en su huésped natural, estando bajo el control de dos loci de apareamiento que controlan la fusión celular y la patogénesis. En condiciones de cultivo axénico, hemos demostrado que el hongo es capaz de infectar plantas filogenéticamente distantes del maíz; y hemos desarrollado condiciones para completar su ciclo de vida mediante la interacción del patógeno con callos de maíz separados por una membrana que evita su contacto físico. Por medio del control de pH del medio de cultivo, hemos logrado la transición de levadura a micelio in vitro. Otro aspecto importante es la naturaleza de las vías de transducción de las señales que regulan el comportamiento sexual, la morfogénesis y la patogénesis de U. maydis. Se ha demostrado que éstas involucran vías MAPK y PKA que operan antagónicamente en la morfogénesis y en forma cooperativa en la patogénesis. No cabe duda que en el futuro, U.maydis seguirá siendo útil para desvelar los secretos de la patogénesis de los hongos en las plantas y deleitar a los amantes de la buena cocina.

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Section: Infección En Huéspedes No Naturalesunclassified

Ustilago maydis: ascenso de un hongo mexicano de la gastronomía local al mundo científico

Herrera

2014

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“…U. maydis is a member of the smut fungi, which infect a large number of dicotyledonous and monocotyledonous plants and cause severe economic losses to growers (Banuett and Herskowitz, 1996;Martínez-Espinoza et al, 2002). Within this group, U. maydis represents the most tractable system offering a comprehensive repertoire of molecular tools (Kahmann and Kämper, 2004).…”

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confidence: 99%

Dissecting Defense-Related and Developmental Transcriptional Responses of Maize during Ustilago maydis Infection and Subsequent Tumor Formation

Basse

2005

Plant Physiology

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Infection of maize (Zea mays) plants with the smut fungus Ustilago maydis triggers the formation of tumors on aerial parts in which the fungal life cycle is completed. A differential display screen was performed to gain insight into transcriptional changes of the host response. Some of the genes strongly up-regulated in tumors showed a pronounced developmental expression pattern with decreasing transcript levels from basal to apical shoot segments, suggesting that U. maydis has the capacity to extend the undifferentiated state of maize plants. Differentially expressed genes implicated in secondary metabolism were Bx1, involved in biosynthesis of the cyclic hydroxamic acid 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one, and a novel putative sesquiterpene cyclase gene U. maydis induced (Umi)2. Together with the up-regulation of Umi11 encoding a cyclotide-like protein this suggests a nonconventional induction of plant defenses. Explicitly, U. maydis was resistant to 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one but susceptible to its benzoxazolinone derivative 6-methoxy-2-benzoxazolinone. Infection studies of isolated leaves with U. maydis and Colletotrichum graminicola provided evidence for coregulation of Umi2 and PR-1 gene expression, with mRNA levels strongly determined by the extent of fungal colonization within tissue. However, in contrast to Umi2, transcript levels of PR-1 remained low in plants infected with wild-type U. maydis but were 8-fold elevated upon infection with an U. maydis mutant strongly attenuated in pathogenic development. This suggests that U. maydis colonization in planta suppresses a classical defense response. Furthermore, comparative expression analysis uncovered distinct transcriptional programs operating in the host in response to fungal infection and subsequent tumor formation.

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“…A large number of plants typically must be inoculated and screened from a plant population to potentially identify plants resistant to the pathogen of interest 6,23 . Therefore, it is important to utilize an inoculation method that reliably delivers the pathogen cell suspension culture in between the plant leaves and that this is done with relative ease and little manipulation of the plants.…”

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confidence: 99%

A Rapid and Efficient Method for Assessing Pathogenicity of <em>Ustilago maydis</em> on Maize and Teosinte Lines

Chavan

Smith

2014

JoVE

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Maize is a major cereal crop worldwide. However, susceptibility to biotrophic pathogens is the primary constraint to increasing productivity. U. maydis is a biotrophic fungal pathogen and the causal agent of corn smut on maize. This disease is responsible for significant yield losses of approximately $1.0 billion annually in the U.S.1 Several methods including crop rotation, fungicide application and seed treatments are currently used to control corn smut 2 . However, host resistance is the only practical method for managing corn smut. Identification of crop plants including maize, wheat, and rice that are resistant to various biotrophic pathogens has significantly decreased yield losses annually [3][4][5] . Therefore, the use of a pathogen inoculation method that efficiently and reproducibly delivers the pathogen in between the plant leaves, would facilitate the rapid identification of maize lines that are resistant to U. maydis. As, a first step toward indentifying maize lines that are resistant to U. maydis, a needle injection inoculation method and a resistance reaction screening method was utilized to inoculate maize, teosinte, and maize x teosinte introgression lines with a U. maydis strain and to select resistant plants.Maize, teosinte and maize x teosinte introgression lines, consisting of about 700 plants, were planted, inoculated with a strain of U. maydis, and screened for resistance. The inoculation and screening methods successfully identified three teosinte lines resistant to U. maydis. Here a detailed needle injection inoculation and resistance reaction screening protocol for maize, teosinte, and maize x teosinte introgression lines is presented. This study demonstrates that needle injection inoculation is an invaluable tool in agriculture that can efficiently deliver U. maydis in between the plant leaves and has provided plant lines that are resistant to U. maydis that can now be combined and tested in breeding programs for improved disease resistance. Video LinkThe video component of this article can be found at

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The Ustilaginales as Plant Pests and Model Systems

Cited by 131 publications

References 177 publications

Ustilago maydis: ascenso de un hongo mexicano de la gastronomía local al mundo científico

Ustilago maydis: ascenso de un hongo mexicano de la gastronomía local al mundo científico

Dissecting Defense-Related and Developmental Transcriptional Responses of Maize during Ustilago maydis Infection and Subsequent Tumor Formation

A Rapid and Efficient Method for Assessing Pathogenicity of <em>Ustilago maydis</em> on Maize and Teosinte Lines

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