RESUMEN

FLOWERING LOCUS T (FT) and TERMINAL FLOWER1 (TFL1) proteins share highly conserved amino acid residues but they play opposite regulatory roles in promoting and repressing the flowering response, respectively. Previous substitution models and functional analysis have identified several key amino acid residues which are critical for the promotion of flowering. However, the precise relationship between naturally occurring FT/TFL1 homologs and the mechanism of their role in flowering is still unclear. In this study, FT/TFL1 homologs from eight Rosaceae species, namely, Spiraea cantoniensis, Pyracantha fortuneana, Photinia serrulata, Fragaria ananassa, Rosa hybrida, Prunus mume, Prunus persica and Prunus yedoensis, were isolated. Three of these homologs were further characterized by functional analyses involving site-directed mutagenesis. The results showed that these FT/TFL1 homologs might have diverse functions despite sharing a high similarity of sequences or crystal structures. Functional analyses were conducted for the key FT amino acids, Tyr-85 and Gln-140. It revealed that TFL1 homologs cannot promote flowering simply by substitution with key FT amino acid residues. Mutations of the IYN triplet motif within segment C of exon 4 can prevent the FT homolog from promoting the flowering. Furthermore, physical interaction of FT homologous or mutated proteins with the transcription factor FD, together with their lipid-binding properties analysis, showed that it was not sufficient to trigger flowering. Thus, our findings revealed that the divergence of flowering time modulating by FT/TFL1 homologs is independent to interaction and binding activities.

RESUMEN

Corn expressing insecticidal proteins derived from Bacillus thuringiensis (Bt corn) has increased in usage in the United States from 8% of total corn acreage in 1996 to 67% in 2012. Because of this increase, it is important to be able to monitor the fate and transport of the insecticidal Bt proteins to evaluate environmental exposure and effects. Accurate and validated methods are needed to quantify these proteins in environmental matrices. A method to extract Bt Cry1Ab proteins from 3 soil types using a 10× phosphate-buffered saline with Tween buffer and a commercially available enzyme-linked immunosorbent assay (ELISA) was validated through a series of 6 tests. The validation process for Cry1Ab extractions in soil has not yet been reported in the scientific literature. The extraction buffer and each soil matrix were tested and validated for the ELISA. Extraction efficiencies were 41%, 74%, and 89% for the 3 soil types and were significantly correlated with the organic matter content of the soil. Despite low recoveries, consistent results with low coefficients of variation allowed for accurate measurements. Through validating this method with 3 different soils, a sensitive, specific, precise, and accurate quantification of Bt Cry1Ab was developed. The validation process can be expanded and implemented in other environmental matrices, adding consistency to data across a wide range of samples.

Asunto(s)

Proteínas Bacterianas/aislamiento & purificación , Endotoxinas/aislamiento & purificación , Proteínas Hemolisinas/aislamiento & purificación , Contaminantes del Suelo/aislamiento & purificación , Toxinas de Bacillus thuringiensis , Proteínas Bacterianas/química , Endotoxinas/química , Ensayo de Inmunoadsorción Enzimática , Sedimentos Geológicos/química , Proteínas Hemolisinas/química , Illinois , Fosfatos/química , Polisorbatos/química , Compuestos de Potasio/química , Ríos , Cloruro de Sodio/química , Suelo/química , Contaminantes del Suelo/química , Tensoactivos/química , Árboles , Zea mays

RESUMEN

American ginseng (Panax quinquefolius L.) is grown in some regions of the USA and Canada and marketed for its health promoting attributes. While cultivation of this plant species has taken place in North America for over 100 years, there are many challenges that need to be addressed. In this article, the current production method used by growers is described and the challenges and opportunities for research on this valuable plant are discussed. These include studies on pharmacological activity, genetic diversity within the species, genetic improvement of currently grown plants, molecular characterization of gene expression, and management of diseases affecting plant productivity. The current research developments in these areas are reviewed and areas requiring further work are summarized. Additional research should shed light on the nature of the bioactive compounds and their clinical effects, and the molecular basis of active ingredient biosynthesis, and provide more uniform genetic material as well as improved plant growth, and potentially reduce losses due to pathogens.