Expression and purification of the transcription factor StMsn2 from Setosphaeria turcica in Escherichia coli

Background: In Saccharomyces cerevisiae, Msn2, which acts as a key transcription factor downstream the MAPKHOG cascade pathway, also regulates the expression of genes related to stress responses. However, little is known about the regulation mechanisms of the transcription factor in Setosphaeria turcica. Results: In this study, a zinc finger DNA-binding protein, designated as StMSN2, was cloned from S. turcica. Sequencing results showed that StMSN2 had a 1752 bp open reading frame (ORF), which was interrupted by an intron (135 bp) and encoded a putative 538-amino acid protein. Phylogenetic analysis further revealed that StMsn2 was more closely related to Msn2 of Aspergillus parasiticus. StMSN2 was cloned into the pET-28a vector with His (Histidine) tags and induced with 1 mM IPTG (isopropyl-ß-D-thiogalactoside) at 37°C. The recombinant His-tagged StMsn2 was purified, and a band of size approximately 58.8 kDa was obtained. The high specificity of the polyclonal antibody Msn2-2 was detected with the StMsn2 protein from S. turcica and prokaryotic expression system, respectively. Conclusions: A new gene, named StMSN2, with 1617 bp ORF was cloned from S. turcica and characterized using bioinformatics methods. StMsn2 was expressed and purified in a prokaryotic system. A polyclonal antibody, named Msn2-2, against StMsn2 with high specificity was identified.

Identification of Bipolaris bicolor and Bipolaris sorokiniana on wheat seeds (Triticum aestivum L) in Brazil

Diseases caused in wheat by Helminthosporium spp. have led to considerable yield and production losses. Different species in this genus are associated with wheat seeds. In Brazil, spot blotch in wheat is caused by Bipolaris sorokiniana (Sacc) Schoem, and another fungus Bipolaris bicolor (Mitra) Shoem that has been also isolated from wheat seeds. The current study was undertaken to identify the most frequent fungus species that normaly infects wheat seeds and compared them with B. sorokiniana. The fungus Bipolaris bicolor (Mitra) Shoem., isolated from wheat seeds cultivar IAPAR, was identified by taxonomic methods and compared with the fungus Bipolaris sorokiniana (Sacc.) Shoem., in relation to growth characteristics on the seeds, as well as to growth characteristics in PDA and morphology of the structures. Type of colony observed on the seeds is important for the differentiation between the fungus species. Bipolaris sorokiniana presented black colonies, which were well-adherent to the seeds, whereas B. bicolor presented grayish, aerial, cotton-like colonies. The size of the conidia also differed in length and width, and B. bicolor presented the smallest dimensions. In relation to septa, B. bicolor conidia presented deep ones, with dark color bases, but seldom presented dark apex. Bipolaris sorokiniana presented homogenous color.

Doenças causadas por Helminthosporium spp. em trigo, causam consideráveis perdas na produção. Diferentes espécies do gênero do fungo podem ser encontradas em sementes. No caso do Brasil, a mancha foliar do trigo tem sido causada por Bipolaris sorokiniana (Sacc) Schoem, entretanto, outro fungo como Bipolaris bicolor (Mitra) Shoem tem sido isolado de sementes do trigo. O objetivo do presente trabalho foi identificar as espécies de fungo que normalmente infectam sementes de trigo e comparar com a mais comum B. sorokiniana. O fungo Bipolaris bicolor (Mitra) Shoem., isolado de sementes de trigo var. IAPAR, foi identificado por métodos taxonômicos e comparado com o fungo Bipolaris sorokiniana (Sacc.) Shoem. em relação ao crescimento sobre as sementes bem como às características culturais no meio BDA e morfologia das estruturas. O tipo de colônia observada sobre as sementes é importante para diferenciar as espécies entre si. O fungo B. sorokiniana apresentou colônias de cor preta sendo bem aderidas às sementes, enquanto B. bicolor apresentou colônias aéreas acinzentadas e com aspecto cotonoso. O tamanho dos conídios também diferenciaram no comprimento e largura onde os valores menores corresponderam a B. bicolor. Em relação aos septos, os conídios de B. bicolor apresentavam septo "profundo", com coloração escura na base e, raras vezes no ápice. Os conídios de B. sorokiniana apresentaram coloração homogênea.

Especies graminícolas de bipolaris, drechslera y curvularia en la V región (Chile): aspectos morfológicos y biogeográficos / Graminicolous species of bipolaris, drechslera and curvularia in the V región (Chile): morphologic and biogeographic aspects

Mediante cultivos en cámara húmeda y agar agua, se estudió la presencia y distribución biogeográfica, del género curvularia y helminthosporium "complex", en 19 gramíneas silvestres recolectadas en 20 localidades de la V región, Chile. En los 88 aislamientos fúngicos, se detectaron los géneros: bipolaris (77,2 por ciento), curvularia (12,5 por ciento) y drechslera (10,2 por ciento). Bipolaris cynodontis (45,5 por ciento) y b. australiensis (27,3 por ciento), fueron las especies dominantes, mientras los integrantes de los géneros curvularia (c. lunata ( 1,1 por ciento) y c. affinis ( 1,1 por ciento) fueron esporádicas. Las gramíneas y localidades con mayor diversidad de especies fueron respectivamente: sorghum (5) y zea (3); Curacaví (6 taxa) y Quillota (3 taxa). Se efectuaron claves dicotómicas, se compararon algunas características morfofisiológicas de las especies dominantes y se revisó brevemente en la literatura algunas patologías humanas causadas por estas dematiáceas

Acción del hongo Helminthosporium sacharii en la acumulación de alcaloides en suspensiones celulares de Catharanthus roseus G Don / Helminthosporium sacharii fungus action in alkaloid accumulation in cell suspension of Catharanthus roseus G Don

Se ha demostrado que cuando se produce un estrés en las células vegetales, se estimula o induce la producción de metabolitos secundarios; para lograr estos fines se han empleado, fundamentalmente, agentes químicos y biológicos. En el presente trabajo se adicionó un homogeneizado del hongo Helminthosporium sacharii a una suspensión celular de Catharanthus roseus (L) G Don, para observar su efecto sobre la estimulación de la producción de alcaloides en dicha especie vegetal. Se realizaron diversas determinaciones químicas y biológicas en el momento de la inoculación del hongo, y a los 4, 8 y 12 días posteriores a su inoculación. Los resultados evidenciaron un ligero incremento de la producción de alcaloides por la suspensión de C. roseus inoculada, observándose que la tetrahidroalstonina fue el alcaloide mayormente producido en todos los tiempos de incubación