Polyamines and WOX genes in the recalcitrance to plant conversion of somatic embryos of Habanero pepper (Capsicum chinense Jacq.)

In order to determine the role of polyamines in the formation and development of the somatic embryos of Capsicum chinense, the effect of different concentrations (0, 0.01, 0.1, and 1.0 mM) of Putrescine, Spermidine and Spermine on the efficiency and morphology of the embryos was evaluated. The results show that none of the three polyamines evaluated had a significant effect on the number of embryos formed, except Spermidine (1 mM), which caused a significant reduction in their numbers, in comparison with the control treatment. However, the most noteworthy result was observed in the treatment containing 0.1 mM of Spermine. The embryos developed in this treatment showed harmonic apex-radicle development, pale-green coloration and the formation of two tiny cotyledonary leaves. Real-time PCR was used to analyze the differential expression of the WUS, WOX1 and WOX3 genes in somatic embryos treated with Spermine and untreated, including the zygotic embryo. The transcript levels of the genes analyzed were found to differ significantly between both types of embryos (somatic and zygotic), with the zygotic embryos presenting a higher level of transcripts; however, compared to the untreated somatic embryos, the somatic embryos treated with Spermine showed an increase in the transcript levels of the three genes analyzed (WUS, WOX1 and WOX3); the WOX1 gene in particular presented an accumulation pattern similar to that of the zygotic embryo of the species. Keywords: Somatic embryos, zygotic embryos, polyamines, transcript patterns and morphology.

Model Identification of the Ice-Cream Crystallization Process

Proceedings of the 11th International Congress on Engineering and Food (ICEF11), Athens, Greece, 2011The quality of ice-cream is at a large extent determined by the smooth texture and creamy mouth feel which are closely related to the crystal size and product viscosity. Model based computer aided process engineering may enable the design of optimal operation conditions so as to maximize ice-cream quality while minimizing, for example, energy consumption. In this regard, the development of predictive mathematical models describing the ice-cream crystallization process is object of intensive research. However, mathematical modelling is a time consuming task that involves several steps from the definition of the questions to be addressed to the development of a final model with satisfactory predictive capabilities. In this concern, model identification, plays a crucial role in model development since it involves structure characterisation, identifiability analysis, parameter estimation and experimental design. The objective of this work is to perform a complete study of the model identification for the ice-cream crystallization process. A simple yet accurate mathematical model relating the process inputs and outputs was derived, based on the method of moments. The AMIGO toolbox (Advanced Model Identification using global optimization) was used to iteratively identify model unknowns from experimental data obtained in the pilot plant located at CEMAGREF and to design new experiments to improve model predictive capabilitiesThe authors acknowledge the financial support received from the 7th Framework Programme of the European Union (CAFE Project – Large Collaborative Project KBBE-2007-2-3-01) and the Spanish Ministry of Science and Innovation (MICINN Project AGL2008-05267-C03-01)N

Floral Biology Studies in Habanero pepper (Capsicum chinense Jacq.) to Implement in a Cross-Breeding Program

Knowledge of the reproductive biology of a species is fundamental in order to develop an efficient program of genetic improvement by hybridization. The viability of the pollen, anther dehiscence, receptivity of the stigma and the anthesis of 12 improved lines of Habanero pepper were studied to develop a cross-breeding program. Among the results, the greatest number of flowers in anthesis was quantified at 8:00 a.m. for most genotypes. The dehiscence of the anther differed significantly in stages evaluated, observing in flower buds 100% of the closed anthers. The receptivity was positive in all the stages evaluated (before, during and after anthesis) and in all the genotypes, the most outstanding being the genotype AKN-08, which presented 100% of receptivity in the three stages evaluated. The viability of the pollen varied among the different conservation times evaluated (0, 24 and 48 h) while the highest percentage of viability (80%) and the largest number of seeds per fruit (56) were obtained when recently collected pollen was used (0 time). These results will have an important repercussion on the improvement of the Habanero pepper by increasing the efficiency of the programs to obtain hybrids and/or improved varieties

Indirect Somatic Embryogenesis: An Efficient and Genetically Reliable Clonal Propagation System for <i>Ananas comosus</i> L. Merr. Hybrid “MD2”

The objective of this study was to establish an efficient—direct or indirect—regeneration system for pineapple (Ananas comosus L.) plants, with a high rate of multiplication and that would preserve the genetic identity of the donor genotype (Hybrid ‘MD2’) in the regenerated plants. Ten treatments, with different concentrations of 2,4-Dichlorophenoxyacetic (2,4-D) and Picloram (P), in the absence or presence of 6-Benzylaminopurine (BAP), were used for in vitro morphogenesis induction, as well as histological and molecular techniques, in order to characterize the morphogenic responses induced. Significant differences between treatments tested, to induce callus and buds, were assessed by the Kruskal Wallis method and the Mann–Whitney U-tests. Different pineapple regeneration routes were identified, showing the high regeneration potential of this species. The medium containing 2 mg L−1 2,4-D and 2 mg L−1 BAP, where indirect somatic embryogenesis occurred, was selected as the most efficient treatment, with an average of 120 somatic embryos per explant, differing significantly from the rest of the treatments. It was also demonstrated that the pineapple plants regenerated in vitro preserved the genetic identity of the donor genotype, which represents a high degree of confidence for the application of indirect somatic embryogenesis for A. comusus clonal propagation

Indirect Somatic Embryogenesis: An Efficient and Genetically Reliable Clonal Propagation System for Ananas comosus L. Merr. Hybrid &ldquo;MD2&rdquo;

The objective of this study was to establish an efficient&mdash;direct or indirect&mdash;regeneration system for pineapple (Ananas comosus L.) plants, with a high rate of multiplication and that would preserve the genetic identity of the donor genotype (Hybrid &lsquo;MD2&rsquo;) in the regenerated plants. Ten treatments, with different concentrations of 2,4-Dichlorophenoxyacetic (2,4-D) and Picloram (P), in the absence or presence of 6-Benzylaminopurine (BAP), were used for in vitro morphogenesis induction, as well as histological and molecular techniques, in order to characterize the morphogenic responses induced. Significant differences between treatments tested, to induce callus and buds, were assessed by the Kruskal Wallis method and the Mann&ndash;Whitney U-tests. Different pineapple regeneration routes were identified, showing the high regeneration potential of this species. The medium containing 2 mg L&minus;1 2,4-D and 2 mg L&minus;1 BAP, where indirect somatic embryogenesis occurred, was selected as the most efficient treatment, with an average of 120 somatic embryos per explant, differing significantly from the rest of the treatments. It was also demonstrated that the pineapple plants regenerated in vitro preserved the genetic identity of the donor genotype, which represents a high degree of confidence for the application of indirect somatic embryogenesis for A. comusus clonal propagation