Resistance gene homologues in Theobroma cacao as useful genetic markers.

Resistance gene homologue (RGH) sequences have been developed into useful genetic markers for marker-assisted selection (MAS) of disease resistant Theobroma cacao. A plasmid library of amplified fragments was created from seven different cultivars of cacao. Over 600 cloned recombinant amplicons were evaluated. From these, 74 unique RGHs were identified that could be placed into 11 categories based on sequence analysis. Primers specific to each category were designed. The primers specific for a single RGH category amplified fragments of equal length from the seven different cultivars used to create the library. However, these fragments exhibited single-strand conformational polymorphism (SSCP), which allowed us to map six of the RGH categories in an F(2) population of T. cacao. RGHs 1, 4 and 5 were in the same linkage group, with RGH 4 and 5 separated by less than 4 cM. As SSCP can be efficiently performed on our automated sequencer, we have developed a convenient and rapid high throughput assay for RGH alleles.

Phylogeny of Amaryllidaceae tribe Amaryllideae based on nrDNA ITS sequences and morphology.

We present the results of cladistic analyses of morphology, nrDNA ITS sequences, and a combination of the two for tribe Amaryllideae of the Amaryllidaceae. The morphologically based analysis supports the recognition of Amaryllis as sister to two major clades, equivalent to Snijman and Linder's (1996, Annals of the Missouri Botanical Garden 83: 362-386) Crininae and Amaryllidinae (less Amaryllis). A single tree is found with a successively weighted ITS sequence matrix. Amaryllis and Boophone form a grade at the base of the tree. All the other genera are included in two clades conforming to Snijman and Linder's (1996) subtribes Amaryllidinae (less Amaryllis, thus now Strumariinae) and Crininae (less Boophone). Within Strumariinae, Strumaria sensu lato is resolved as polyphyletic. Strumaria subg. Gemmaria is sister to the rest of the subtribe. Hessea is monophyletic only if Namaquanula is excluded. The monotypic Carpolyza is embedded within Strumaria sensu stricto. The consensus of the combined analysis is highly resolved, and most similar to the sequence topology. Based on the results of the combined analyses, the major clades are recognized as subtribes, and Carpolyza is placed into synonymy under Strumaria.

Systematics of Amaryllidaceae based on cladistic analysis of plastid sequence data.

Cladistic analyses of plastid DNA sequences rbcL and trnL-F are presented separately and combined for 48 genera of Amaryllidaceae and 29 genera of related asparagalean families. The combined analysis is the most highly resolved of the three and provides good support for the monophyly of Amaryllidaceae and indicates Agapanthaceae as its sister family. Alliaceae are in turn sister to the Amaryllidaceae/Agapanthaceae clade. The origins of the family appear to be western Gondwanaland (Africa), and infrafamilial relationships are resolved along biogeographic lines. Tribe Amaryllideae, primarily South African, is sister to the rest of Amaryllidaceae; this tribe is supported by numerous morphological synapomorphies as well. The remaining two African tribes of the family, Haemantheae and Cyrtantheae, are well supported, but their position relative to the Australasian Calostemmateae and a large clade comprising the Eurasian and American genera, is not yet clear. The Eurasian and American elements of the family are each monophyletic sister clades. Internal resolution of the Eurasian clade only partially supports currently accepted tribal concepts, and few conclusions can be drawn on the relationships of the genera based on these data. A monophyletic Lycorideae (Central and East Asian) is weakly supported. Galanthus and Leucojum (Galantheae pro parte) are supported as sister genera by the bootstrap. The American clade shows a higher degree of internal resolution. Hippeastreae (minus Griffinia and Worsleya) are well supported, and Zephyranthinae are resolved as a distinct subtribe. An Andean clade marked by a chromosome number of 2n = 46 (and derivatives thereof) is resolved with weak support. The plastid DNA phylogenies are discussed in the context of biogeography and character evolution in the family.

Antineoplastic agents, 301. An investigation of the Amaryllidaceae genus Hymenocallis.

Seven species (and one cultivated variety) of Hymenocallis (Amaryllidaceae) and the related Pancratium maritima, representing a broad geographical selection, were investigated as sources of pancratistatin [1] now undergoing preclinical development as an anticancer agent. Pancratistatin [1] was found to be a constituent of H. speciosa (Singapore), H. variegated (Singapore), H. pedalis (Seychelles), H. expansa (Bermuda), H. sonoranensis (Mexico), and P. maritimum (Israel). Only two species of Hymenocallis failed to yield one or more of the related cell-growth inhibitory isocarbostyrils such as narciclasine [3a], 7-deoxynarciclasine [3b], and 7-deoxy-trans-dihydronarciclasine [2].

Antineoplastic agents, 256. Cell growth inhibitory isocarbostyrils from Hymenocallis.

The bulbs of Hymenocallis littoralis, collected in Hawaii and horticulturally grown in Arizona, and bulbs of Hymenocallis caribaea and Hymenocallis latifolia, collected in Singapore, were found to contain a cytotoxic, isocarbostyril-type biosynthetic product, 7-deoxy-trans-dihydronarciclasine [2]. This new compound inhibited the cytopathicity and/or replication of various viruses. Companion cytotoxic constituents of H. littoralis and Hymenocallis sp. were found to be pancratistatin [1], narciclasine [5], and 7-deoxynarciclasine [4]. These four compounds, along with four other closely related compounds, were comparatively evaluated in the National Cancer Institute's in vitro cytotoxicity panel. Although there were striking differences in overall potency, some of the compounds shared a highly characteristic differential cytotoxicity profile against the 60 diverse human tumor cell lines comprising the NCI panel. As a group, the melanoma subpanel lines were most sensitive; certain individual lines within other subpanels (eg., NSC lung, colon, brain, renal) were as much as a thousand-fold or more sensitive than the less sensitive lines.

Host suitability of Ixora spp. for the Root-knot Nematodes Meloidogyne incognita Race 1 and M. javanica.

Eight commonly cultivated Ixora species or cultivars were tested for their suitability as hosts and their level of tolerance to Meloidogyne incognita race 1 and M. javanica in a greenhouse study. Twenty weeks postinoculation with 5,000 eggs per pot, M. incognita race 1 and M. javanica produced galls and formed egg masses on roots of all eight Ixora species or cultivars tested. However, only M. javanica-infected 'Petite Yellow' and 'Maui' had decreases (P