Biomedical subjects

Pilar García-Agustín

Publications and source records attributed to Pilar García-Agustín.

6 recordsLinked to original sources

PubMed2006

Priming: getting ready for battle.

Infection of plants by necrotizing pathogens or colonization of plant roots with certain beneficial microbes causes the induction of a unique physiological state called "priming." The primed state can also be induced by treatment of plants with various natural and synthetic compounds. Primed plants display either faster, stronger, or both activation of the various cellular defense responses that are induced following attack by either pathogens or insects or in response to abiotic stress. Although the phenomenon has been known for decades, most progress in our understanding of priming has been made over the past few years. Here, we summarize the current knowledge of priming in various induced-resistance phenomena in plants.

Aminobutyrates↗

PubMed2005

An engineered plant that accumulates higher levels of heavy metals than Thlaspi caerulescens, with yields of 100 times more biomass in mine soils.

Nicotiana glauca transformed with TaPCS1 was tested for its application in phytoremediation. When plantlets were grown in mine soils containing Cu, Zn, and Pb (42, 2600, and 1500 mg kg(-1)) the plant showed high levels of accumulation especially of Zn and Pb. Adult plants growing in mine soils containing different heavy metal concentrations showed a greater accumulation as well as an extension to a wider range of elements, including Cd, Ni and B. The overexpressed gene confers up to 9 and 36 times more Cd and Pb accumulation in the shoots under hydroponic conditions, and a 3- and 6-fold increase in mining soils. When the hyperaccumulator Thlaspi caerulescens was compared, the results were higher values of heavy metal and Boron accumulation, with a yield of 100 times more biomass. Thlaspi was unable to survive in mining soils containing either a level higher than 11000 mg kg(-1) of Pb and 4500 mg kg(-1) of Zn, while engineered plants yielded an average of 0.5 kg per plant.

Biodegradation, Environmental↗

PubMed2005

Control of the phytopathogen Botrytis cinerea using adipic acid monoethyl ester.

The in vitro and in vivo antifungal activity of adipic acid monoethyl ester (AAME) on the necrotrophic pathogen Botrytis cinerea has been studied. This chemical effectively controlled this important phytopathogen, inhibited spore germination and mycelium development at non-phytotoxic concentrations. The effectiveness of AAME treatment is concentration-dependent and influenced by pH. Spore germination in the presence of AAME is stopped at a very early stage, preventing germ tube development. In addition, cytological changes such as retraction of the conidial cytoplasm in the fungus are observed. AAME was also found to act on membrane integrity, affecting permeability without exhibiting lytic activity, as described previously for other antifungal compounds. Polyamine content in the mycelium of B. cinerea was also affected in response to AAME treatment, resulting in putrescine reduction and spermine accumulation similar to a number of antifungal agents. Microscopic observation of treated conidia after inoculation on tomato leaves suggested that inhibited spores are not able to attach to and penetrate the leaf. Finally, AAME completely suppressed the grey mould disease of tomato fruits under controlled inoculation conditions, providing evidence for its efficacy in a biological context and for the potential use of this chemical as an alternative fungicide treatment.

Adipates↗

PubMed2004

Characterization of tomato endo-beta-1,4-glucanase Cel1 protein in fruit during ripening and after fungal infection.

The tomato (Lycopersicon esculentum Mill.) endo-beta-1,4-glucanase (EGase) Cel1 protein was characterized in fruit using specific antibodies. Two polypeptides ranging between 51 and 52 kDa were detected in the pericarp, and polypeptides ranging between 49 and 51 kDa were detected in locules. The polypeptides recognized by Cel1 antiserum in fruit are within the size range predicted for Cel1 protein and could be derived from heterogeneous glycosylation. Cel1 protein accumulation was examined throughout fruit ripening. Cel1 protein appears in the pericarp at the stage in which many ripening-related changes start, and remains present throughout fruit ripening. In locules, Cel1 protein is already present at the onset of fruit ripening and remains constant during fruit ripening. This pattern of expression supports a possible role for this EGase in the softening of pericarp tissue and in the liquefaction of locules that takes place during ripening. The accumulation of Cel1 protein was also analyzed after fungal infection. Cel1 protein and mRNA levels are down-regulated in pericarp after Botrytis cinerea infection but are not affected in locular tissue. The same behavior was observed when fruits were infected with Penicillium expansum, another fungal pathogen. Cel1 protein and mRNA levels do not respond to wounding. These results support the idea that the tomato Cel1 EGase responds to pathogen infection and supports a relationship between EGases, plant defense responses and fruit ripening.

Botrytis↗

PubMed2003

Enzymatic and non-enzymatic antioxidant responses of Carrizo citrange, a salt-sensitive citrus rootstock, to different levels of salinity.

In several plant species, oxidative stress has been shown to be one of the causes of damage produced by salinity. In order to assess the implication of oxidative stress in the reported sensitivity of the citrus rootstock Carrizo citrange to salt stress, 5-month-old seedlings were grown with increasing NaCl concentrations added to the watering solution. As an indicator of oxidative damage, malondialdehyde content was measured. The antioxidant capability of the plants was determined by measuring superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activities together with the non-enzymatic antioxidant activity. As additional physiological responses to the stress, 1-aminocyclopropane-1-carboxilic acid and proline accumulation were assessed. Data indicate that Carrizo citrange responded to salt-induced oxidative stress by increasing enzymatic and non-enzymatic antioxidant defenses proportionally to the extent of the stress imposed, and that in all plants the malondialdehyde content remained at a moderate level. We suggest that the important deleterious effects reported in Carrizo citrange grown under high NaCl concentrations are mainly due to a cellular intoxication by Cl(-) ions and not to the salt-induced oxidative stress.

Adaptation, Physiological↗

PubMed2002

Induction of protection against the necrotrophic pathogens Phytophthora citrophthora and Alternaria solani in Lycopersicon esculentum Mill. by a novel synthetic glycoside combined with amines.

1,2,3,4-tetra-O-acetyl-6-ethyladipate-beta- D-glucopyranose (TOGE), a glycoside derivative of adipic acid monoethyl ester and 1,2,3,4-tetra-O-acetyl-beta- D-glucopyranose, was synthesized and the resistance-inducing activity shown by TOGE-1 (TOGE plus furfurylamine) and TOGE-2 (TOGE plus 1,3-diaminepropane) was assayed. TOGE-1 and TOGE-2 protected tomato plants against two different fungal pathogens Phytophthora citrophthora and Alternaria solani. Foliar treatments at very low concentrations (2.5 mg l(-1) TOGE, 0.5 mg l(-1) amine) clearly reduced the disease incidence for both pathogens. TOGE-2 application was the most effective on intact plants as well as on detached leaves, reducing fungal growth by more than 46% with respect to control plants. On the other hand TOGE-1 treatment reduced fungal advance by 21%. These results demonstrate a high protective effect against fungal infections for both chemicals. A possible direct antimicrobial effect was discounted due to the weak activity observed in vitro against these pathogens at the low concentrations used in plants. TOGE-2 treatment clearly activates resistance against both pathogens and improves the protective effect previously shown by FGA mixture (adipic acid monoethyl ester, 1,2,3,4-tetra-O-acetyl-beta- D-glucopyranose and furfurylamine) [V. Flors et al. (2001) J Agric Food Chem 49:2569-2575]. The obtained results indicate that TOGE-1 and TOGE-2 act as resistance inducers. Although their mode of action is still unknown, pre-challenge studies have demonstrated the induction of the phenylpropanoid pathway and antioxidant activities. Both chemicals have demonstrated a beneficial effect on plant development, increasing chlorophyll and protein contents, photosynthetic rate and water-use efficiency. The improvement of plant growth and development produced by these treatments suggests crop tolerance to these chemicals, although effective formulations that are safe to humans must be developed before this technology can be used commercially.

Adipates↗