Uses, traditional management, perception of variation and preferences in ackee (Blighia sapida K.D. Koenig) fruit traits in Benin: implications for domestication and conservation.

BACKGROUND: Blighia sapida is a woody perennial multipurpose fruit tree species native to the Guinean forests of West Africa. The fleshy arils of the ripened fruits are edible. Seeds and capsules of the fruits are used for soap-making and all parts of the tree have medicinal properties. Although so far overlooked by researchers in the region, the tree is highly valued by farmers and is an important component of traditional agroforestry systems in Benin. Fresh arils, dried arils and soap are traded in local and regional markets in Benin providing substantial revenues for farmers, especially women. Recently, ackee has emerged as high-priority species for domestication in Benin but information necessary to elaborate a clear domestication strategy is still very sketchy. This study addresses farmers' indigenous knowledge on uses, management and perception of variation of the species among different ethnic groups taking into account also gender differences. METHODS: 240 randomly selected persons (50% women) belonging to five different ethnic groups, 5 women active in the processing of ackee fruits and 6 traditional healers were surveyed with semi-structured interviews. Information collected refer mainly to the motivation of the respondents to conserve ackee trees in their land, the local uses, the perception of variation, the preference in fruits traits, the management practices to improve the production and regenerate ackee. RESULTS: People have different interests on using ackee, variable knowledge on uses and management practices, and have reported nine differentiation criteria mainly related to the fruits. Ackee phenotypes with preferred fruit traits are perceived by local people to be more abundant in managed in-situ and cultivated stands than in unmanaged wild stands, suggesting that traditional management has initiated a domestication process. As many as 22 diseases have been reported to be healed with ackee. In general, indigenous knowledge about ackee varies among ethnic and gender groups. CONCLUSIONS: With the variation observed among ethnic groups and gender groups for indigenous knowledge and preference in fruits traits, a multiple breeding sampling strategy is recommended during germplasm collection and multiplication. This approach will promote sustainable use and conservation of ackee genetic resources.

Transferability of Simple Sequence Repeat (SSR) Markers Developed in Litchi chinensis to Blighia sapida (Sapindaceae).

Ackee (Blighia sapida, Sapindaceae) is a multipurpose fruit tree species of high economic importance, native to the Guinean forests of West Africa, and belongs to the same family as that of lychee (Litchi chinensis). In this study, a set of 12 primer pairs for simple sequence repeats (SSRs) previously developed for lychee has been evaluated for polymorphism in 16 ackee trees from different populations. Seven primer pairs have been found to be transferable, and four have revealed polymorphisms. However, the average number of alleles per locus has dropped from 4.9 for lychee to 3.7 for ackee. Characterization of the four polymorphic markers in 279 individuals belonging to14 different ackee populations from Benin has revealed that the numbers of alleles per locus range from two to 14 with a mean number of 5.8. The observed and expected heterozygosities range between 0.020 to 0.359 and 0.020 to 0.396, respectively.

The Clk2 and Clk3 dual-specificity protein kinases regulate the intranuclear distribution of SR proteins and influence pre-mRNA splicing.

The three members of the Clk family of kinases (Clk1, 2, and 3) have been shown to undergo conserved alternative splicing to generate catalytically active (Clk) and inactive (ClkT) isoforms. The prototype, murine Clk1 (mClk1), is a nuclear dual-specificity kinase that can interact with, and cause the nuclear redistribution of, SR proteins. In this study, we demonstrate that the human Clk2 and Clk3 (hClk2 and 3) are also found within the nucleus and display dual-specificity kinase activity. The truncated isoforms, hClk2(T) and hClk3(T), colocalize with SR proteins in nuclear speckles. We also show catalytically active hClk2 and hClk3 cause the redistribution of SR proteins and can regulate the alternative splicing of a model precursor mRNA substrate in vivo.

In vivo regulation of alternative pre-mRNA splicing by the Clk1 protein kinase.

Controlled expression of cellular and viral genes through alternative precursor messenger RNA (pre-mRNA) splicing requires serine/arginine-rich (SR) proteins. The Clk1 kinase, which phosphorylates SR proteins, is regulated through alternative splicing of the Clk1 pre-mRNA, yielding mRNAs encoding catalytically active and truncated inactive polypeptides (Clk1 and Clk1T, respectively). We present evidence that Clk1 and Clk1T proteins regulate the splicing of Clk1 and adenovirus pre-mRNAs in vivo. The peptide domain encoded by the alternatively spliced exon of Clk1 is essential for the regulatory activity of the Clk1 kinase. This is the first direct demonstration of an in vivo link between alternative splicing and protein kinase activity.

Alternative splicing of STY, a nuclear dual specificity kinase.

The LAMMER subfamily of kinases has been conserved throughout evolution, and its members are thought to play important roles in the regulation of cellular growth and differentiation programs. STY is a murine LAMMER kinase which has been implicated in the control of PC12 cell differentiation. Multiple transcripts are derived from the Sty gene, and their relative abundance is developmentally regulated. Alternative splicing of the primary Sty transcript generates mRNAs encoding full-length catalytically active (STY) and truncated, kinase-deficient polypeptides. Both STY and its truncated isoform, STYT, are localized in the nucleus and are capable of heterodimerizing. We also demonstrate that STY functions as a dual specificity kinase in mammalian cells.

Cell adhesion properties of myelin-associated glycoprotein in L cell fibroblasts.

Myelin-associated glycoprotein (MAG) is a cell surface molecule expressed by oligodendrocytes and Schwann cells. In order to determine whether MAG expression can confer adhesive properties to cells which normally do not aggregate in suspension, the cDNA encoding the long form of MAG (L-MAG) was introduced into L cell fibroblasts by retroviral infection. Clonal L cell lines expressing MAG were then subjected to a cell aggregation assay. Our results indicate that L-MAG can function as an intercellular adhesion molecule in a heterologous cell system. A critical threshold value of L-MAG expression was required for cell aggregation to occur. The adhesive properties of these cells were specific to MAG, since monoclonal antibodies directed against its extracellular domain inhibited aggregation. Furthermore, the adhesion was found to be calcium- and temperature-independent. Cell sorting experiments demonstrated that L-MAG-expressing cells bind in a heterotypic fashion to parental L cell fibroblasts. These results suggest that L-MAG can function as a heterotypic cell adhesion molecule recognizing a cell surface molecule(s) expressed by L cells.