Cristina Navarro

Conservation of Arabidopsis Flowering Genes in Model Legumes

The model plants Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa) have provided a wealth of information about genes and genetic pathways controlling the flowering process, but little is known about the corresponding pathways in legumes. The garden pea (Pisum sativum) has been used for several decades as a model system for physiological genetics of flowering, but the lack of molecular information about pea flowering genes has prevented direct comparison with other systems. To address this problem, we have searched expressed sequence tag and genome sequence databases to identify flowering-gene-related sequences from Medicago truncatula, soybean (Glycine max), and Lotus japonicus, and isolated corresponding sequences from pea by degenerate-primer polymerase chain reaction and library screening. We found that the majority of Arabidopsis flowering genes are represented in pea and in legume sequence databases, although several gene families, including the MADS-box, CONSTANS, and FLOWERING LOCUS T/TERMINAL FLOWER1 families, appear to have undergone differential expansion, and several important Arabidopsis genes, including FRIGIDA and members of the FLOWERING LOCUS C clade, are conspicuously absent. In several cases, pea and Medicago orthologs are shown to map to conserved map positions, emphasizing the closely syntenic relationship between these two species. These results demonstrate the potential benefit of parallel model systems for an understanding of flowering phenology in crop and model legume species.

Flower development in pisum sativum: from the war of the whorls to the battle of the common primordia

The ontogeny of pea (Pisum sativum L.) flowers, as in many legume and nonlegume plant species, proceeds through a very different sequence of events from the same process in Antirrhinum majus and Arabidopsis thaliana. Using scanning electron microscopic analysis, we have characterized the early development of wild-type pea flowers and selected morphological characters or markers to break it down into different developmental stages. We used these markers as tools to characterize early alterations in flower development of several pea floral homeotic mutants. These mutants display phenotypes resembling those of: (1) floral meristem identity mutations, frondosus (brac); (2) class A mutations, calix carpellaris (cc); (3) class B mutations, stamina pistilloida (stp-1 and stp-2); and (4) class C mutations, petalosus (pe). According to the homeotic transformations observed in the pea floral mutants, it would appear feasible that the identity and developmental pattern of the four organ types in pea flowers are governed by at least the same three developmental functions, A, B, and C, proposed for the two model systems. However, our results suggest that, in pea, although these functions do have a similar role in the specification of organ identity shown by their counterparts in Arabidopsis or Antirrhinum, they may differ in the control of other processes, such as floral determinacy, organ number, or leaf development. The more remarkable features of pea flower ontogeny were the existence of four common primordia to petals and stamens, the early carpel primordium initiation, and the abaxial-adaxial unidirectional initiation of organ primordia within each different floral whorl, in contrast to the centripetal and sequential floral ontogeny in other plants. Organ differentiation within each of these common primordia appears to be a complex process that plays a central role in the ontogeny of pea flowers. Analysis of flower developmental pea homeotic mutants suggests that A, B, and C functions are necessary for the correct differentiation of organs from common primordia and that, in addition to its role in the specification of petals and stamens, B function, would be involved in conferring common primordia identity. Copyright 1999 Wiley-Liss, Inc.

Influence of Ground Predators on the Survival of the Mediterranean Fruit Fly Pupae, Ceratitis capitata , in Spanish Citrus Orchards

A survey of predaceous ground arthropods was conducted in two citrus orchards in Valencia, Spain, and their role as predators of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) pupae was evaluated under field and laboratory conditions. A total of 2959 predaceous arthropods were collected in pitfall traps in the two orchards from July 2003 to September 2004. Ants (Hymenoptera) were the most abundant group (83.61%), followed by Staphylinidae (7.77%), Araneae (5.24%), Dermaptera (2.13%), Carabidae (0.64%) and Cicindelidae (0.61). Pupae disappearance rates were higher during the warmer months of the year, from May to October, and in the orchard with the largest ant population. In the warm season, the mean survival of C. capitata pupae was 35.7±6.2% and 14.3±6.7%, respectively, in both orchards. Patterns of predation, inferred from broken or abnormal pupae, were more frequently observed in the colder months, from November to April, when spiders, Staphylinidae and other predators were present. In the cold season, the combined effect of predation and low temperature led to an adult emergence rate of 26.7±9.9% and 13.0±7.5% in both orchards. In no-choice laboratory trials, all predator species tested fed at significantly different rates on C. capitata pupae. Preliminary data show that the Carabids, Pseudophonus rufipes (Duftschmid) and Harpalus distinguendus (Degeer), were the most voracious species, consuming more than one pupa per day.

Functional conservation of PISTILLATA activity in a pea homolog lacking the PI motif.

Current understanding of floral development is mainly based on what we know from Arabidopsis (Arabidopsis thaliana) and Antirrhinum majus. However, we can learn more by comparing developmental mechanisms that may explain morphological differences between species. A good example comes from the analysis of genes controlling flower development in pea (Pisum sativum), a plant with more complex leaves and inflorescences than Arabidopsis and Antirrhinum, and a different floral ontogeny. The analysis of UNIFOLIATA (UNI) and STAMINA PISTILLOIDA (STP), the pea orthologs of LEAFY and UNUSUAL FLORAL ORGANS, has revealed a common link in the regulation of flower and leaf development not apparent in Arabidopsis. While the Arabidopsis genes mainly behave as key regulators of flower development, where they control the expression of B-function genes, UNI and STP also contribute to the development of the pea compound leaf. Here, we describe the characterization of P. sativum PISTILLATA (PsPI), a pea MADS-box gene homologous to B-function genes like PI and GLOBOSA (GLO), from Arabidopsis and Antirrhinum, respectively. PsPI encodes for an atypical PI-type polypeptide that lacks the highly conserved C-terminal PI motif. Nevertheless, constitutive expression of PsPI in tobacco (Nicotiana tabacum) and Arabidopsis shows that it can specifically replace the function of PI, being able to complement the strong pi-1 mutant. Accordingly, PsPI expression in pea flowers, which is dependent on STP, is identical to PI and GLO. Interestingly, PsPI is also transiently expressed in young leaves, suggesting a role of PsPI in pea leaf development, a possibility that fits with the established role of UNI and STP in the control of this process.

Efficacy and satisfaction with transcutaneous electrostimulation of the posterior tibial nerve in overactive bladder syndrome

Objective: Overactive bladder is a disease with a high prevalence. The management is difficult, because different demographic, social or economic aspects converge. Our objective was to evaluate the efficacy and satisfaction in patients with overactive bladder treated with transcutaneous electrostimulation of the posterior tibial nerve. Methods: This was a prospective and descriptive study of 45 patients with overactive bladder (with or without detrusor overactivity) resistant to pharmacological treatment. Patients received a weekly session for 12 weeks, with a duration of 30 minutes for each of the sessions. There was a screening after 12 sessions, after which if there had been no response, treatment was suspended and maintenance sessions were not continued (six twice-monthly sessions and three monthly sessions). It was considered that the treatment had been effective when it was possible to decrease the number of events, except the maximum voiding volume, the objective of which was to increase. The results were evaluated using a 3-day voiding diary, an overactive bladder short form questionnaire and a satisfaction level questionnaire. Statistical analysis was performed using IBM SPSS Statistics version 19.0. Independent variables with a normal distribution were examined using the t-test. The Wilcoxon signed-rank test was used to compare the averages of the quantitative variables without a normal distribution. Satisfaction was analysed by a binary and ordinal regression analysis, univariate and multivariate. A P value less than 0.05 was considered statistically significant. Results: All the parameters of the study improved to a statistically relevant degree: frequency, nocturia, urgency, maximum voided volume, urge urinary incontinence. The overactive bladder short form questionnaire score improved but was not statistically significant. Conclusions: The use of transcutaneous electrostimulation of the posterior tibial nerve is a safe, effective and minimally invasive alternative in the treatment of overactive bladder when pharmacological treatment has failed. Patients had a good objective and subjective response in our study. Level of evidence: 4.Objective:Overactive bladder is a disease with a high prevalence. The management is difficult, because different demographic, social or economic aspects converge. Our objective was to evaluate the ...