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Anthracnose caused by Colletotrichum spp. is one of the major diseases of avocado that affects the quality of its fruit and reducing production. Difficulties in controlling and eradicating the disease have been reported in previous years. Therefore, the objective was to identify and characterize Colletotrichum spp. strains as causal agent of anthracnose in the ‘Hass’ avocado through morphological, pathogenic and molecular studies, which were isolates from the principal production zones of avocado in the state of Nayarit, Mexico. Fruits with typical disease symptoms were collected from four communal lands belonging to Xalisco and Tepic, in Nayarit, Mexico. A collection of 20 isolates was obtained, which 13 were identified as C. gloeosporioides , one of C. hymenocallidis , five of C. siamense and one of C. tropicale , where the most pathogenic was a strain of Colletotrichum siamense and a strain of Colletotrichum gloeosporioides. It is important to note that it is the first report of C. hymenocallidis and C. siamense in avocado. Palabras clave: Avocado fruit, diversity, pathogenicity, variability., La antracnosis, ocasionada por Colletotrichum spp., es una de las principales enfermedades del aguacate que afecta la calidad del fruto y merma su producción. En los últimos años se han reportado dificultades para la prevención y erradicación de esta enfermedad. Por ello, el objetivo del presente trabajo fue identificar y caracterizar cepas de Colletotrichum spp . como agente causal de antracnosis en el aguacate ‘Hass’ . , mediante estudios morfológicos, patogénicos y moleculares, a partir de aislamientos provenientes de las principales zonas productoras de aguacate del estado de Nayarit, México. Se recolectaron frutos con síntomas típicos de la enfermedad, colectados en cuatro ejidos pertenecientes a los municipios de Xalisco y Tepic, Nayarit, México. Se obtuvo una colección de 20 aislamientos, de los cuales 13 son de C. gloeosporioides , una C. hymenocallidis , cinco C. siamense y una de C. tropicale , siendo la más patógena el Colletotrichum gloeosporioides . Es importante destacar que este es el primer reporte de C. hymenocallidis y C. siamense en aguacate. Palabras clave: Aguacate, diversidad, patogenicidad, variabilidad.

Anthracnose caused by Colletotrichum spp. is one of the major diseases of avocado that affects the quality of its fruit and reducing production. Difficulties in controlling and eradicating the disease have been reported in previous years. Therefore, the objective was to identify and characterize Colletotrichum spp. strains as causal agent of anthracnose in the ‘Hass’ avocado through morphological, pathogenic and molecular studies, which were isolates from the principal production zones of avocado in the state of Nayarit, Mexico. Fruits with typical disease symptoms were collected from four communal lands belonging to Xalisco and Tepic, in Nayarit, Mexico. A collection of 20 isolates was obtained, which 13 were identified as C. gloeosporioides , one of C. hymenocallidis , five of C. siamense and one of C. tropicale , where the most pathogenic was a strain of Colletotrichum siamense and a strain of Colletotrichum gloeosporioides. It is important to note that it is the first report of C. hymenocallidis and C. siamense in avocado. Palabras clave: Avocado fruit, diversity, pathogenicity, variability., La antracnosis, ocasionada por Colletotrichum spp., es una de las principales enfermedades del aguacate que afecta la calidad del fruto y merma su producción. En los últimos años se han reportado dificultades para la prevención y erradicación de esta enfermedad. Por ello, el objetivo del presente trabajo fue identificar y caracterizar cepas de Colletotrichum spp . como agente causal de antracnosis en el aguacate ‘Hass’ . , mediante estudios morfológicos, patogénicos y moleculares, a partir de aislamientos provenientes de las principales zonas productoras de aguacate del estado de Nayarit, México. Se recolectaron frutos con síntomas típicos de la enfermedad, colectados en cuatro ejidos pertenecientes a los municipios de Xalisco y Tepic, Nayarit, México. Se obtuvo una colección de 20 aislamientos, de los cuales 13 son de C. gloeosporioides , una C. hymenocallidis , cinco C. siamense y una de C. tropicale , siendo la más patógena el Colletotrichum gloeosporioides . Es importante destacar que este es el primer reporte de C. hymenocallidis y C. siamense en aguacate. Palabras clave: Aguacate, diversidad, patogenicidad, variabilidad.

Solvent effects on the UV–vis absorption spectra and molecular properties of four models of the photoactive yellow protein (PYP) chromophore have been studied with ASEP/MD, a sequential quantum mechanics/molecular mechanics method. The anionic trans-p-coumaric acid (pCA–), thioacid (pCTA–), methyl ester (pCMe–), and methyl thioester (pCTMe–) derivatives have been studied in gas phase and in water solution. We analyze the modifications introduced by the substitution of sulfur by oxygen atoms and hydrogen by methyl in the coumaryl tail. We have found some differences in the absorption spectra of oxy and thio derivatives that could shed light on the different photoisomerization paths followed by these compounds. In solution, the spectrum substantially changes with respect to that obtained in the gas phase. The n → π1* state is destabilized by a polar solvent like water, and it becomes the third excited state in solution displaying an important blue shift. Now, the π → π1* and π → π2* states mix, and we find contributions from both transitions in S1 and S2. The presence of the sulfur atom modulates the solvent effect and the first two excited states become practically degenerate for pCA– and pCMe– but moderately well-separated for pCTA– and pCTMe–.