Phaseolus Species: In Vitro Culture and the Accumulation of Isoflavone Phytoalexins and Other Secondary Metabolites

Abstract

The Phaseolae (family Leguminosae) are grown agronomically as a grain legume for both human and animal nutrition. Of the four species, Phaseolus acutifolius (tepary bean), P. coccineus (scarlet runner bean), P. lunatus (lima and butter bean), and P. vulgaris (known variously as common, field, green, snap, wax or French bean) are grown extensively (Hall 1991; Langer and Hill 1991). Related species, such as P. angularis and P. aureus have recently been reclassified as belonging to the genus Vigna and will not be considered further in this Chapter. All of the Phaseolae originate from southern or central America and are grown for their dried seeds or fleshy pods for human consumption. After harvesting, the vines may also be used as fresh or silaged cattle feed. Of all the bean species, P. vulgaris is the most important agronomic crop, being a major dietary component in Latin America and Africa. P. vulgaris was first domesticated in 5000 B.C. in central America and was distributed to the rest of the world by the Spanish in the 16th century. The major world producer of P. vulgaris is the USA where after harvest with typical yields of 1.5 t/ha, it is either dried or canned as baked beans (Langer and Hill 1991). Similarly, P. lunatus is also grown for its beans with its cultivation largely confined to the USA with yields as high as 1.7 t/ha (Langer and Hill 1991). The beans of P. acutifolius are used in soups both in central America and Africa.