Changes in the phenylalanine ammonia lyase activity, total phenolic compounds, and flavonoids in Prosopis glandulosa treated with cadmium and copper.

The aim of the present work is to evaluate the changes on the phenylalanine ammonia lyase (PAL) activity, phenolic compounds accumulation and photochemical efficiency in leaves of P. glandulosa treated with Cd2+ (0.001 M) and Cu2+ (0.52 M) concentrations for 96 h under hydroponic conditions. The results showed that only leaves treated with copper had a decrease in photochemical efficiency and leaf epidermal polyphenols in P. glandulosa leaves after 96 h of exposure. On the other hand the reverse-phase HPLC analysis revealed higher levels of phenolic compound (gallic, vanillic and caffeic acids) and flavonoids (rutin and kaempferol-3-O-glucosides) in plant leaves from Cu and Cd-treatments with respect to control plants. Finally, highest increments in PAL activity was observed in extracts of leaves treated with Cu and Cd (about 205 and 284%), respectively, with respect to control plants after 96 h treatment. These suggest that activation of phenylpropanoid pathway represent a source of nonenzymatic antioxidants that protect at P. glandulosa against oxidative stress when exposed to cadmium and copper. Hence future studies are necessary to elucidate the participation of phenylpropanoid pathway in the reduction of metal toxicity in Prosopis species.

[Antifungal effect of phenolic and carotenoids extracts from chiltepin (Capsicum annum var. glabriusculum) on Alternaria alternata and Fusarium oxysporum]. / Efecto antifúngico de extractos fenólicos y de carotenoides de chiltepín (Capsicum annum var. glabriusculum) en Alternaria alternata y Fusarium oxysporum.

The effect of phenolic and carotenoid extracts from chiltepin fruits on mycelial growth and the inhibition of conidial germination of Alternaria alternata and Fusarium oxysporum were investigated in the present work. Phenolic extracts inhibited mycelial growth of A.alternata by 38.46%, and significantly reduced conidial germination on the fifth day after treatment to 92% in relation to control. No significant changes were observed in the inhibition of mycelial growth in Fusarium oxysporum; however, the number of germinated conidia was reduced, showing 85% inhibition five days after treatment in relation to control. Moreover, carotenoid extracts showed 38.5% inhibition of mycelial growth and 85.3% inhibition of conidial germination of A.alternata, five days after treatment. Carotenoid extracts showed less inhibition of mycelial growth (20.3%) in F.oxysporum, with respect to A.alternata; while there was greater inhibition of conidial germination (96%) on the fifth day after treatment. Phenolic and carotenoid extracts from chiltepin may be a promising alternative as a natural fungicide against fungi of agricultural importance.

Cell viability and leakage of electrolytes in Avicennia germinans exposed to heavy metals.

The effect of heavy metal stress on the cell viability and leakage of electrolytes of Avicennia germinans leaf discs was investigated by the tissue tolerance test. Foliar discs were incubated with different Cd2+ or CU2+ concentrations for 24 h; thereafter, the cell membrane stability of the tissue was assayed by the cell viability Evans blue and leakage electrolytes methods. The results indicated that electrolyte leakage of the leaf discs increased 24 h after exposure to heavy metal stress, as shown by a reduction of the cell viability by 30% in discs exposed to higher doses of Cd2+ (0.546 M) and Cu2+ (0.7 M), respectively. Additionally, the histological analysis of the leaf discs exposed to heavy metal stress revealed that at higher Cd2+ and/or Cu2+ concentrations an increase in the intercellular spaces and destruction of mesophyll cells was observed 24 h after exposure. In summary, the biochemical and structural changes observed in foliar tissues of A. germinans suggest that higher cadmium and copper concentrations may result in structural changes and altered physiological characters in leaves.

Efecto antifúngico de extractos fenólicos y de carotenoides de chiltepín (Capsicum annum var. glabriusculum) en Alternaria alternata y Fusarium oxysporum / Antifungal effect of phenolic and carotenoids extracts from chiltepin (Capsicum annum var. glabriusculum) on Alternaria alternata and Fusarium oxysporum

En el presente estudio se evaluó el efecto de extractos fenólicos y de carotenoides procedentes de frutos de chiltepín sobre el crecimiento micelial y la germinación de conidios de Alternaria alternata y Fusarium oxysporum, 2 importantes hongos causantes de podredumbres en frutas y hortalizas. Los extractos fenólicos presentaron una inhibición en el crecimiento micelial de A. alternata del 38,46 %, y redujeron significativamente la germinación de conidios al quinto día después del tratamiento al 92 % en relación al control. No se observaron cambios significativos en el crecimiento micelial de F. oxysporum, pero sí se redujo significativamente al 85 % en relación al control, el número de conidios germinados a los 5 días de tratamiento. Los extractos de carotenoides mostraron una inhibición del 38,5 % en el crecimiento micelial y del 85,3 % en la germinación de conidios de A. alternata, 5 días después del tratamiento. Frente a F. oxysporum, dichos extractos presentaron menor inhibición del crecimiento micelial (20,3 %), mientras que hubo una mayor inhibición en la germinación de conidios (96 %). Los extractos fenólicos y de carotenoides de chiltepín pueden ser una alternativa promisoria de importancia agrícola como fungicidas naturales.

The effect of phenolic and carotenoid extracts from chiltepin fruits on mycelial growth and the inhibition of conidial germination of Alternaria alternata and Fusarium oxysporum were investigated in the present work. Phenolic extracts inhibited mycelial growth of A. alternata by 38.46%, and significantly reduced conidial germination on the fifth day after treatment to 92% in relation to control. No significant changes were observed in the inhibition of mycelial growth in Fusarium oxysporum; however, the number of germinated conidia was reduced, showing 85% inhibition five days after treatment in relation to control. Moreover, carotenoid extracts showed 38.5% inhibition of mycelial growth and 85.3% inhibition of conidial germination of A. alternata, five days after treatment. Carotenoid extracts showed less inhibition of mycelial growth (20.3%) in F. oxysporum, with respect to A. alternata; while there was greater inhibition of conidial germination (96%) on the fifth day after treatment. Phenolic and carotenoid extracts from chiltepin may be a promising alternative as a natural fungicide against fungi of agricultural importance.

Detección de geminivirus asociados a la alstroemeria (alstroemeria l.) En villa guerrero, estado de México / Detection of geminivirus associated to alstroemeria (alstroemeria l.) In villa guerrero, state of Mexico / Detecção de geminivírus associados a alstroemeria (alstroemeria l.) Em villa guerrero, estado do México

En plantaciones de alstroemeria (Alstroemeria L.) de Villa Guerrero, Estado de México, se han detectado plantas con síntomas similares a los inducidos por geminivirus en otros cultivos hortícolas. En dichas plantaciones también se ha observado la presencia de la mosquita blanca, considerada como el vector más eficiente de estos virus. El objetivo del presente trabajo fue detectar la presencia de geminivirus en plantas de alstroemeria. Mediante PCR, usando los iniciadores MotCP2118/MotCP2123, se obtuvo un segmento de ~600pb, similar al del control positivo correspondiente a chile infectado con el begomovirus pepper huasteco yellow vein virus (PHYVV, antes pepper huasteco virus) en plantas sintomáticas, mientras que en las asintomáticas la detección fue negativa. Plantas de Nicotiana glutinosa, N. benthamiana, N. rustica, N. tabacum var. xanthi y Datura stramonium inoculadas por biobalística con ADN total obtenido de alstroemerias con síntomas y positivas a PHYVV mediante PCR, mostraron mosaicos leves y deformación de hojas, mientras que en plantas de Capsicum annuum se observaron mosaicos, necrosis en nervaduras y abultamientos en hojas. Con el ADN de estas plantas también se obtuvieron bandas correspondientes al PHYVV, pero en las monocotiledóneas bombardeadas, incluyendo alstroemeria, no fue detectado el fragmento. La secuencia de oligonucleótidos de los productos de PCR mostró 98% de homología con el begomovirus PHYVV. Aunque no fue posible reproducir en alstroemeria los síntomas observados en campo, sí se evidenció mediante PCR la presencia de un geminivirus similar al PHYVV en tejido de plantas sintomáticas.

In alstroemeria (Alstroemeria L.) plantations located in Villa Guerrero, Mexico State, plants with symptoms similar to those induced by geminivirus in other horticultural crops have been detected. In addition, the presence of whiteflies, which are considered the most efficient vectors of these viruses, has been observed in these plantations. The goal of this work was to detect the presence of this geminivirus species in alstroemeria plants. By means of PCR analysis using primers MotCP2118/MotCP2123, a fragment of ~600pb similar to the amplicon obtained from PHYVV-infected positive control was amplified only from symptomatic plants. Nicotiana glutinosa, N. benthamiana, N. rustica, N. tabacum var. xanthi and Datura stramonium plants were inoculated by bombardment with total DNA obtained from symptomatic alstroemerias and positive to PHYVV by means of PCR. Inoculated plants showed mild mosaics and deformation of leaves, whereas in the leaves of Capsicum annum plants, mosaics, vein necrosis and blisters were observed. Using DNA from these plants as template in PCR, amplicons corresponded to PHYVV were also obtained; however, in bombarded monocotyledons, including alstroemeria, this fragment was not detected. The sequence of oligonucleotides from the PCR products showed 98% homology to PHYVV geminivirus. Even though symptoms presented by alstroemeria plants in the field were not reproduced, the presence of a geminivirus similar to PHYVV in tissue of symptomatic plants was evidenced through PCR.

Em plantações de alstroemeria (Alstroemeria L.) de Villa Guerrero, Estado do México, se tem detectado plantas com sintomas similares aos induzidos por geminivírus em outros cultivos hortícolas. Em ditas plantações também tem sido observada a presença da mosquinha branca, considerada como o vetor mais eficiente destes vírus. O objetivo do presente trabalho foi detectar a presença de geminivírus em plantas de alstroemeria. Mediante PCR, usando os iniciadores MotCP2118/MotCP2123, obteve-se um segmento de ~600pb, similar ao do controle positivo correspondente a chile infectado com o begomovírus pepper huasteco yellow vein virus (PHYVV, antes pepper huasteco virus) em plantas sintomáticas, enquanto que nas assintomáticas a detecção foi negativa. Plantas de Nicotiana glutinosa, N. benthamiana, N. rustica, N. tabacum var. xanthi e Datura stramonium inoculadas por biobalística com DNA total obtido de alstroemerias com sintomas e positivas a PHYVV mediante PCR, mostraram mosaicos leves e deformação de folhas, enquanto que em plantas de Capsicum annuum se observaram mosaicos, necrose em nervaduras e protuberâncias em folhas. Com o DNA destas plantas também se obtiveram bandas correspondentes ao PHYVV, mas nas monocotiledóneas bombardeadas, incluindo alstroemeria, não foi detectado o fragmento. A sequência de oligonucleotídeos dos produtos de PCR mostrou 98% de homologia com o begomovírus PHYVV. Embora não foi possível reproduzir em alstroemeria os sintomas observados em campo, sím foi evidenciada, mediante PCR, a presença de um geminivírus similar ao PHYVV em tecido de plantas sintomáticas.

Los elementos potencialmente tóxicos en las plantas de manglar: una revisión de los mecanismos de tolerancia involucrados / The potentially toxic elements in mangrove plants: a review of the mechanisms of tolerance involved / Os elementos potencialmente tóxicos no manguezal plantas: revisão dos mecanismos de tolerância involucrados

Las plantas de manglar han desarrollado a través de su evolución una serie de mecanismos a nivel celular que le permiten establecerse en ambientes con altas concentraciones de metales. Externamente, involucra la participación de microorganismos rizosféricos, la formación de placas de hierro y modificaciones en sus raíces. A nivel interno, se menciona la participación conjunta de exudados radicales, metalotioneinas, y fitoquelatinas. La comprensión de los mecanismos de tolerancia a metales por las plantas de manglar representa un factor clave en el conocimiento de la fisiología de estas plantas de gran importancia ecológica y biotecnológica. En este trabajo se describen los mecanismos de tolerancia a elementos potencialmente tóxicos presentes en algunas especies de manglares.

Mangroves have developed through evolution a number of potential mechanisms at the cellular level that let them settle in environments with high concentrations of metals. Externally, they involve the participation of rhizosphere microorganisms, the formation of iron plaques and changes in their roots. Internally, they involve the participation of radical exudates, metallothioneins, and phytochelatins. The comprehension of metal tolerance mechanisms by mangroves is a key factor in understanding of the physiology of these plants of great significance to ecology and biotechnology. This paper describes the mechanisms of tolerance to potentially toxic elements present in some species of mangroves.

As plantas de manglar desenvolveram através de sua evolução uma série de mecanismos potenciais a nível celular que lhe permitem se estabelecer em ambientes com altas concentrações de metais: externamente, envolve a participação de microorganismos rizosféricos, a formação de placas de ferro e modificações em suas raízes. Ao nível interno menciona-se a participação conjunta de exudados radicais, metalotioneinas, e fitoquelatinas. O entendimento dos mecanismos de tolerância a metais, pelas plantas de mangue pode representar um fator chave que no conhecimento da fisiologia destas plantas têm grande importância ecológica e biotecnológica. Nesta revisão realiza-se uma breve descrição dos mecanismos de tolerância a elementos potencialmente tóxicos presentes em algumas espécies de manguezais.