<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>1405-3195</journal-id>
<journal-title><![CDATA[Agrociencia]]></journal-title>
<abbrev-journal-title><![CDATA[Agrociencia]]></abbrev-journal-title>
<issn>1405-3195</issn>
<publisher>
<publisher-name><![CDATA[Colegio de Postgraduados]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S1405-31952007000700775</article-id>
<title-group>
<article-title xml:lang="es"><![CDATA[Proceso de infección de la roya de la hoja del trigo (Puccinia triticina Erikson) en genotipos con resistencia parcial]]></article-title>
<article-title xml:lang="en"><![CDATA[Infection process to wheat leaf rust (Puccinia triticina Erikson) in genotipes with partial resistance]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[García-Lara]]></surname>
<given-names><![CDATA[Erika]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Leyva-Mir]]></surname>
<given-names><![CDATA[S. Gerardo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cárdenas-Soriano]]></surname>
<given-names><![CDATA[Elizabeth]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Huerta-Espino]]></surname>
<given-names><![CDATA[Julio]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Sandoval-Islas]]></surname>
<given-names><![CDATA[J. Sergio]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Villaseñor-Mir]]></surname>
<given-names><![CDATA[Eduardo]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Colegio de Postgraduados Campus Montecillo ]]></institution>
<addr-line><![CDATA[ Estado de México]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad Autónoma Chapingo Departamento de Parasitología Agrícola ]]></institution>
<addr-line><![CDATA[Chapingo Estado de México]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,INIFAP Campo Experimental Valle de México ]]></institution>
<addr-line><![CDATA[Chapingo Estado de México]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>11</month>
<year>2007</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>11</month>
<year>2007</year>
</pub-date>
<volume>41</volume>
<numero>7</numero>
<fpage>775</fpage>
<lpage>785</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S1405-31952007000700775&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S1405-31952007000700775&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S1405-31952007000700775&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen: Con el propósito de entender los mecanismos de resistencia parcial que confieren los genes Lr 34, Lr46 y uno aún no designado (Gen 1) a la resistencia prehaustorial que presentan algunos genotipos de trigo con resistencia parcial a roya de la hoja causada por Puccinia triticina, se estudió el proceso de infección en genotipos de trigo que contienen genes con resistencia parcial: Jupateco 73R+Lr34, Avocet+Lr34, Lalbahadur+Lr46 y Lalbahadur+Gen 1, y en genotipos que no contienen el gen: Jupateco 73S-Lr34, Avocet-Lr34 y Lalbahadur. El objetivo fue conocer los mecanismos de resistencia que actúan en el proceso de infección. Se utilizaron las técnicas de tinción con fucsina ácida y microscopía de fluorescencia. En el porcentaje de germinación de las urediosporas de la roya de trigo no hubo diferencias significativas en la comparación múltiple de medias (p&gt;0.05; DMS). Sin embargo, se encontró que Lalbahadur+Lr46 y Lalbahadur+Lr34 presentaron mayor porcentaje de reducción (p&#8804;0.05) en porcentaje de germinación. En cuanto a la formación de apresorios, penetración y formación de vesícula subestomática, se encontraron diferencias significativas (p&#8804;0.05) entre los genotipos Lalbahadur+Lr46 y Lalbahadur+Lr34. En los tejidos de hoja de trigo infectados con roya, por la técnica de inclusión en parafina se observaron daños celulares: colapso, desintegración celular y necrosis. En los genotipos con el gen Lr34 se encontró colapso, desintegración celular y finalmente necrosis en toda la hoja excepto en el haz vascular del genotipo Lalb+Lr34 y en gran parte de la hoja en los genotipos AOC+Lr34 y Jup73R+Lr34. El genotipo con el Gen1 presentó poca necrosis a 86 h de muestreo, por lo que se expresó pronto la resistencia parcial, y en el genotipo con el gen Lr46 se inició la infección con colapso seguida de la desintegración de cloroplastos a las 30 h, y posteriormente la necrosis en toda la hoja excepto en el haz vascular, por lo que manifestó temprano su resistencia. Además, se encontraron papilas en Jupateco 73R 40 h después de la inoculación. De los resultados obtenidos se deduce que Lr34, Lr46 y el Gen1 confieren resistencia prehaustorial, o sea frente al haustorio del hongo, que se asemeja mucho a la resistencia de no hospedante, la cual es de tipo durable.]]></p></abstract>
<abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract: With the purpose to understand partial resistance mechanisms, which the genes Lr34, Lr46, and one gene (Gene 1) not yet named confer to prehaustorial resistance, presented by some wheat genotypes with partial resistance to leaf rust caused by Puccinia triticina, the infection process in wheat genotypes containing genes with partial resistance was studied: Jupateco 73R+Lr34, Avocet+Lr34, Lalbahadur+Lr46, and Lalbahadur+Gene 1, and in genotypes that do not contain the gene: Jupateco 73S-Lr34, Avocet-Lr34, and Lalbahadur. The objective was to recognize the resistance mechanisms which act in the infection process. Staining techniques with fuchsine acid and fluorescence microscopy were employed. In the percentage of urediospore germination of wheat rust, there were no significant differences in multiple comparison of means (p&gt;0.05; DMS). It was found, however, that Lalbahadur+Lr46 and Lalbahadur+Lr34 showed higher percentage of reduction (p&#8804;0.05) in the germination percentage. With respect to the formation of apresoria, penetration, and substomatal bladder formation, significant differences (p&#8804;0.05) between the genotypes Lalbahadur+Lr46 and Lalbahadur+Lr34 were noticed. In the tissues of rust-infected wheat leaf, cell damages were observed by the technique of inclusion in paraffin: collapse, cell disintegration, and necrosis. In the genotypes with gene Lr34, collapse, cell disintegration and finally necrosis were found all over the leaf with exception of the vascular bundle of genotype Lalb+Lr34 and to a great extent of the leaf in genotypes AOC+Lr34 and Jup73R+Lr34. The genotype with Gene 1 presented little necrosis at 86 h of sampling, that is why partial resistance was expressed soon, and in the genotype with gene Lr46, the infection began with collapse, followed by chloroplast disintegration at 30 h, and subsequently necrosis on the entire leaf except the vascular bundle, therefore its resistance became evident soon. Besides, papillae were detected in Jupateco 73R 40 h after inoculation. From the results obtained it is deduced that Lr34, Lr46, and Gene1 confer prehaustorial resistance, or in other words, before the haustorium of the fungus, which is very similar to the resistance of the non-host, that is of the durable type.]]></p></abstract>
<kwd-group>
<kwd lng="es"><![CDATA[Alteraciones celulares]]></kwd>
<kwd lng="es"><![CDATA[cereales]]></kwd>
<kwd lng="es"><![CDATA[fitopatógenos]]></kwd>
<kwd lng="es"><![CDATA[resistencia vegetal]]></kwd>
<kwd lng="es"><![CDATA[signos]]></kwd>
<kwd lng="en"><![CDATA[Cell alterations]]></kwd>
<kwd lng="en"><![CDATA[cereals]]></kwd>
<kwd lng="en"><![CDATA[phyto-pathogens]]></kwd>
<kwd lng="en"><![CDATA[vegetal resistance]]></kwd>
<kwd lng="en"><![CDATA[signs]]></kwd>
</kwd-group>
</article-meta>
</front><back>
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