Although proteinase inhibitor proteins are known to confer insect resistance in transgenic plants, their endogenous roles remain undefined. Here, we describe the expression of a proteinase inhibitor II (PIN2) protein from Solanum americanum in phloem of stems, roots and leaves suggesting a novel endogenous role for PIN2 in phloem. The phloem consists of parenchyma cells, sieve elements (SE), and companion cells (CC) which are in close association with SE. We isolated two cDNAs encoding PIN2, SaPIN2a and SaPIN2b, from a S. americanum cDNA library using a tomato PIN2 cDNA as hybridization probe. SaPIN2a shows 73.6% identity to SaPIN2b. Southern blot analysis confirmed that two genes occur in S. americanum. Northern blot analysis showed that both are wound-inducible and are expressed in flowers. Unlike SaPIN2b and other previously characterized plant PIN2 proteins, SaPIN2a is abundantly expressed in stems. In situ hybridization studies on stem sections showed that SaPIN2a mRNA is expressed in CC and some SE, likely the immature developing SE, of external and internal phloem. Western blot analysis using SaPIN2a-specific antibodies showed SaPIN2a accumulation in stems, leaf midribs and fruits. Immunohistochemical localization, using these antibodies, revealed SaPIN2a expression in external and internal phloem of stem. Immunoelectron microscopy of stem, root and leaf sections further localized SaPIN2a to the CC and predominantly to the SE, particularly the parietal cytoplasm adjacent to the cell wall, the lumen and the sieve-area pores. These results suggest that, other than a possible role in plant defense, SaPIN2a could be involved in regulating proteolysis in the SE.

A proteinase inhibitor II of Solanum americanum is expressed in phloem.

The comparison of alkaloidal profile of delimited species in the 5 locally available taxa of S. nigrum complex were used to establish the boundaries among close taxonomic groups. Several glycoalkaloids (Solasonine, α-Solamargine, β-Solamargine and α-Solanine) and their aglycones (Solasodine and Solanidine) were analysed that were shown to be a valuable tool to resolve the international taxonomic controversy based on morphological characters. HPLC and GC-MS were used for the first time for the analysis of alkaloids in S. nigrum complex. Qualitative and quantitative comparison by cluster analysis demonstrated significant distances among S. chenopodioides and S. villosum as well as in S. americanum and S. nigrum, in their respective clusters, indicated them as distinct species. But S. retroflexum did not show such a marked difference and hence might be regarded as a variety or subspecies of S. nigrum.

Chemotaxonomic value of alkaloids in Solanum nigrum complex

The Morelloid clade, also known as the black nightshades or "Maurella" (Morella), is one of the 10 major clades within Solanum L The pantropical clade consists of 75 currently recognised non-spiny herbaceous and suffrutescent species with simple or branched hairs with or without glandular tips, with a centre of distribution in the tropical Andes A secondary centre of diversity is found in Africa, where a set of mainly polyploid taxa occur A yet smaller set of species is found in Australasia and Europe, including Solanum nigrum L, the type of the genus Solanum Due to the large number of published synonyms, combined with complex morphological variation, our understanding of species limits and diversity in the Morelloid clade has remained poor despite detailed morphological studies carried out in conjunction with breeding experiments Here we provide the first taxonomic overview since the 19th century of the entire group in the Old World, including Africa, Asia, Australia, Europe and islands of the Pacific Complete synonymy, morphological descriptions, distribution maps and common names and uses are provided for all 19 species occurring outside the Americas (ie Africa, Asia, Australia, Europe and islands of the Pacific) We treat 12 species native to the Old World, as well as 7 taxa that are putatively introduced and/or invasive in the region The current knowledge of the origin of the polyploid species is summarised A key to all of the species occurring in the Old World is provided, together with line drawings and colour figures to aid identification both in herbaria and in the field Preliminary conservation assessments are provided for all species

A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae)

There, fed by Food they love, to rankest size, Around the Dwellings Docks and Wormwood rise; Here the strong Mallow strikes her slimy Root, Here the dull Nightshade hangs her deadly Fruit; The Borough, Rev. George Crabbe, 1810. The black nightshade (Solanum nigrum L.) complex consists of a group of plants in the section Solanum of the genus Solanum. Black nightshade is the type for the genus Solanum and the most well-known as a noxious weed species. Black nightshade also has been used around the world as a pot-herb, and the berries are used to bake pies despite its reputation as a poisonous plant (Edmonds and Chweya 1997; Mabberley 1997). The black nightshades form a complex group of mainly herbaceous or shrubby plants that are still not completely resolved taxonomically. Most weed references to black nightshade predating the 1980s simply refer to S. nigrum L. as the species. However, taxonomists now recognize many weedy species within this complex (D'Arcy 1991; Edmonds 1977; Edmonds and Chweya 1997; Mabberley 1997; Schilling 1981). This article will mainly cover the history of black nightshade as recorded in the literature. Current species names will be clarified or identified within the Solanum section where information is available.

The Black Nightshades, Solanum nigrum L. et al.—Poison, Poultice, and Pie1

African nightshades play an important role in meeting the nutritional needs of rural households, and are reported as being particularly rich in protein, vitamin A, iron and calcium. Nightshades are among three top priority African indigenous vegetables identified for improvement and promotion through research. A major constraint facing this objective is the scantiness of taxonomic and nomenclatural knowledge on African nightshades resulting in extensive synonymy and confusion. As a consequence, the toxic species are difficult to discriminate from those with high nutritional value. It is also difficult to identify species with good agronomic traits for genetic enhancement. This study was conducted to identify, characterize, and delimit African nightshade species. Fifty accessions of Solanum section Solanum from eastern, southern and western Africa were raised in a greenhouse at the Botanical and Experimental Garden, Radboud University, Nijmegen, the Netherlands. A descriptor list with 48 vegetative and reproductive characters was developed and used to characterize flowering and fruiting plants. Counting of chromosome was done on root squash preparations from one weekold seedlings, aided by digital enhancement of microscopic images. Nine species were represented in the study material, including two diploids: Solanum americanum , and Solanum chenopodioides ; five tetraploids: Solanum retroflexum , Solanum villosum , Solanum florulentum , Solanum grossidentatum and Solanum tarderemotum ; and two hexaploids: Solanum nigrum and Solanum scabrum . Most of the section Solanum species were distinguishable and easily identified. The exception was S. florulentum and S. tarderemotum which were identified tentatively and assigned respective names, but are difficult to differentiate and require further studies. The S. florulentum/tarderemotum group has three distinguishable variants and further studies are needed to determine the taxonomic status of each as a separate species, subspecies or genotypic/phenotypic variants. Furthermore, S. retroflexum, S. villosum and S. scabrum each had a high degree of within-species variation, and further studies are recommended to determine whether the variations within each constitute subspecies. Key words: Solanum sp ., Identification, Characterization

https://tspace.library.utoronto.ca/bitstream/1807/55378/1/nd07029.pdf

Robert N. Andersen

Papers

The black nightshades (Solanum section Solanum) of the Indian subcontinent

Notes on Economic Plants