Chili Pepper Jojutla Morelos (Capsicum annuum L.), CJ-2018: A Variety Resistant to Bactericera cockerelli.

Chili pepper is a vegetable of worldwide economic and gastronomic importance. The psyllid, Bactericera cockerelli, is an economically important pest in this crop, causing considerable losses in its production. Currently, the application of insecticides is the main way to control B. cockerelli. However, the use of varieties resistant to this insect is a viable alternative for its control and management. In this work, the oviposition rate, development, and survival of B. cockerelli in two native varieties of chili were evaluated. Choice and non-choice trials showed that the B. cockerelli oviposition was reduced on CJ-2018 by 92.17 and 80.18%, respectively, compared to the control. In CM-334, the insect showed a behavior similar to the control in the non-choice test, while in the choice test it laid more eggs on CM-334 compared to the control. The development and survival assay showed that only 1.33% of the eggs managed to reach the adult stage on CJ-2018. In contrast, on CM-334 the survival of B. cockerelli was similar to the control. These results suggest that CJ-2018 presented a resistance based on antixenosis and antibiosis against B. cockerelli.

Detection of Mycobacterium avium subsp. paratuberculosis in reproductive tissue and semen of naturally infected rams.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis (PTB), disease that causes a syndrome of bad nutrient absorption, weight loss and eventually death. The intestine is the main target organ where the infection develops; however, there is evidence of infection by MAP in extra-intestine sites of sheep, including mesenteric nodes and semen. The aim of the study was to identify the presence of MAP in reproductive tissue and semen of infected Pelibuey rams in clinical state of PTB. Seven rams were used in clinical PTB state and a non-infected ram by MAP of the Pelibuey breed, confirmed by serology, nPCR and bacteriological culture, with average weight and age of 57.23 ± 1.73 kg and 2.91 ± 0.17 years, respectively. The presence of MAP was identified in different tissue samples: spleen (1/7, 14.3% and 2/7, 28.6%), small intestine (3/7, 42.9% and 4/7, 57.1%) and mesenteric lymph nodes (3/7, 42.9% and 3/7, 42.9%), with nPCR and culture, respectively. It was also identified in epididymis tissue (1/7, 14.3%), Cowper gland (2/7, 28.6%) and prostate (1/7, 14.3%), using nPCR, although without detection in culture. It was identified in testicular tissue in 42.8% (3/7; culture or nPCR technique), but in 28.6% (2/7) with both techniques. Finally, the presence of MAP was identified in 42.9% (3/7) of semen samples with nPCR; however, it was not detected through culture. In conclusion, the presence of MAP was identified in lymphatic, digestive tissue, and semen; the presence of MAP was reported for the first time in epididymis, Cowper gland, prostate and testicles of infected Pelibuey rams.

Cladosporium cladosporioides and Cladosporium pseudocladosporioides as potential new fungal antagonists of Puccinia horiana Henn., the causal agent of chrysanthemum white rust.

Puccinia horiana Hennings, the causal agent of chrysanthemum white rust, is a worldwide quarantine organism and one of the most important fungal pathogens of Chrysanthemum × morifolium cultivars, which are used for cut flowers and as potted plants in commercial production regions of the world. It was previously reported to be controlled by Lecanicillium lecanii, Cladosporium sphaerospermum, C. uredinicola and Aphanocladium album, due to their antagonistic and hyperparasitic effects. We report novel antagonist species on Puccinia horiana. Fungi isolated from rust pustules in a commercial greenhouse from Villa Guerrero, México, were identified as Cladosporium cladosporioides and Cladosporium pseudocladosporioides based upon molecular analysis and morphological characters. The antagonism of C. cladosporioides and C. pseudocladosporioides on chrysanthemum white rust was studied using light and electron microscopy in vitro at the host/parasite interface. Cladosporium cladosporioides and C. pseudocladosporioides grew towards the white rust teliospores and colonized the sporogenous cells, but no direct penetration of teliospores was observed; however, the structure and cytoplasm of teliospores were altered. The two Cladosporium spp. were able to grow on media containing laminarin, but not when chitin was used as the sole carbon source; these results suggest that they are able to produce glucanases. Results from the study indicate that both Cladosporium species had potential as biological control agents of chrysanthemum white rust.

Oclusión de haces vasculares para evaluar resistencia de caña de azúcar a xanthomonas albilineans / Vascular bundle occlusion as a measure of sugarcane resistance to xanthomonas albilineans / Oclusão de feixes vasculares para avaliar resistência de cana de açucar a xanthomonas albilineans

La evaluación de resistencia de caña de azúcar (Saccharum officinarum L.) a escaldadura de la hoja ha sido realizada sin consideración del porcentaje de daño al sistema vascular. En el presente estudio se analizó la oclusión de haces vasculares del tallo, en la parte basal y apical de la caña de azúcar, para evaluar resistencia a Xanthomonas albilineans (Xa). Se utilizó caña de azúcar de la variedad susceptible Mex 64-1487 y la resistente Co 997, distribuidas en un diseño de bloques al azar con cuatro repeticiones. La inoculación se realizó por inyección en la parte media del tallo de plantas de tres meses de edad, con 3ml de Xa con 2x10(5)UFC/ml o agua estéril. Los muestreos se realizaron a 0, 30, 60, 110 y 213 días después de la inoculación (ddi), cortando dos tallos al azar por repetición. De cada tallo se tomó un nudo de la parte basal y otro de la parte apical, los cuales se colocaron en formaldehido-alcohol-ácido acético. La oclusión se analizó utilizando un diseño completamente al azar con arreglo factorial 2³ con tres repeticiones. La identificación de Xa se realizó utilizando Bio-PCR (colonias bacterianas en la PCR), con los iniciadores PGBL1 y PGBL2, específicos para DNA de Xa. El mayor porcentaje de haces vasculares ocluidos se detectó a los 110 ddi en la parte basal (p£0,05) de ambas variedades. La oclusión de haces vasculares permitió evaluar correctamente la resistencia de Mex 64-1487 y Co 997(p£0,05) utilizando la parte basal del tallo.

The sugarcane (Saccharum officinarum L.) resistance to leaf scald has been studied without consideration of the percentage of damage to the vascular system. In the present study the occlusion of vascular bundles in the basal and apical parts of the sugarcane stalk was analyzed to evaluate the resistance to Xanthomonas albilineans (Xa). The susceptible sugarcane variety Mex 64-1487 and the resistant variety Co 997 were used under a randomized design with four replications. Inoculation was carried out by injection in the middle of the stalk of 3 month old plants, using 3ml of a 2x10(5)UFC/ml bacterial suspension or sterile water. The sampling was done at 0, 30, 60, 110 and 213 days after the inoculation, cutting two stalks by replication. In each plant two nodes from the basal part and two from the apical part were sampled and kept in a formaldehide-alcohol-acetic acid solution, to determine occlusion with a complete randomized design in factorial composition 2³ with three replications. The Xa diagnosis was done employing Bio-PCR (bacterial cells in the PCR) and PGBL1 and PGBL2 DNA specific primers for Xa. The percentage of vascular bundle occlusion was larger in the basal part of the stalk in both varieties (p£0,05). The determination of the vascular bundle occlusion allowed a correct evaluation of the resistance of both Mex 64-1487 and Co 997 (p£0,05), analyzing the lower basal part of the stalk.

A avaliação de resistência de cana de açucar (Saccharum officinarum L.) a escaldadura da folha tem sido realizada sem consideração da porcentagem de dano ao sistema vascular. No presente estudo se analisou a oclusão de feixes vasculares do caule, na parte basal e apical da cana de açucar, para avaliar resistência a Xanthomonas albilineans (Xa). Utilizou-se cana de açucar da variedade suscetível Mex 64-1487 e a resistente Co 997, distribuidas em um desenho aleatório de blocos com quatro repetições. A inoculação se realizou por injeção na parte média do caule de plantas de três meses de idade, com 3ml de Xa com 2x10(5)UFC/ml ou agua estéril. As amostragens foram realizdas a 0, 30, 60, 110 e 213 dias após a inoculação (dai), cortando dois caules aleatoriamente por repetição. De cada caule foi retirado um nó da parte basal e outro da parte apical, os quais foram colocados em formaldehido-álcool-ácido acético. A oclusão se analisou utilizando um desenho completamente aleatório com arranjo fatorial 2³ com três repetições. A identificação de Xa se realizou utilizando Bio-PCR (colônias bacterianas na PCR), com os iniciadores PGBL1 e PGBL2, específicos para DNA de Xa. A maior porcentagem de feixes vasculares ocluídos foi detectada aos 110 dai na parte basal (p£0,05) de ambas as variedades. A oclusão de feixes vasculares permitiu avaliar corretamente a resistência de Mex 64-1487 e Co 997(p£0,05) utilizando a parte basal do caule.