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This work presents an updated list of the species belonging to the genus Phaseolus following its definition of 1978; it is the outcome of the study of eighty-six herbaria and forty-one explorations in the field in the period 1978–2019. There are currently eighty-one species, all of them native to the Americas, most of them distributed north of Panama (the genus is a migrant into South America), and half of them being known by very few records. They thrive in warm to mild temperate, seasonally dry, open forest, with rains under favorable temperature, from sea level up to 3,000 m. The recent increase in the number of recognized species is due to the endemic ones; this in combination with few unclassified specimens may indicate that the total number of species is not final yet, and that field work will be rewarding. [ABSTRACT FROM AUTHOR]

Evidence is presented about the presence of Phaseolus microcarpus in Costa Rica, while it was previously reported northwards in other Central American countries and Mexico. Fourteen populations are currently known, four from the Peninsula of Nicoya, and ten are in the tropical dry forest of the mainland of this country. [ABSTRACT FROM AUTHOR]

The taxonomic classification of the wild Lima bean complex needs to be assessed to select species for use in breeding programs and to identify genetic resources for conservation. The objectives of this study were to determine the genetic relationships among, and the phylogeny of, wild Lima bean (Phaseolus lunatus L.) and related species (P. augusti Harms, P. bolivianus Piper, P. pachyrrhizoides Harms, and P. rosei Piper) from South America and to identify specific genetic reserves for conservation. These relationships were investigated by means of amplified restriction fragment length polymorphism (AFLPs) on total genomic DNA. The 122 accessions formed a cluster that was distant from common bean (P. vulgaris L.), confirming earlier morphology and hybridology data. Two gene pools of wild Lima beans were confirmed. One was widely distributed in neotropical lowlands, while the other was restricted to the western Andes, in Ecuador and northern Peru. The study also revealed the existence of a third group of wild Lima bean distributed in the Departments of Boyaca and Cundinamarca, Colombia. The three species P. augusti, P. bolivianus, and P. pachyrrhizoides differed very little, certainly not sufficiently to merit a separate taxonomic ranking at the species level. The accessions could be grouped instead according to four geographic origins: Ecuador and northern Peru; Department of Junin, Peru; Departments of Cuzco and Apurimac, Peru; and Bolivia and northwestern Argentina. Results from this study should result in a better selection of parental materials in breeding programs and point to areas where germplasm collections and conservation are needed., THE GENUS Phaseolus includes five grain legumes of worldwide or regional economic importance, and approximately 50 species, all of neotropical origin (Delgado Salinas, 1985; Lackey, 1983; Marechal et al., 1978). [...]

A new wild bean found in the mountainous range "Fila Cruces" of southeastern Costa Rica is described. To date, only four populations are known from different sites on the slopes of Cerro Anguciana and "Fila Cruces" where it seems to be endemic. The differences (slender curved racemes, small oval acuminate primary and pedicelar bracts, lilac inner face of standard, white wings) are presented with closely related species such as P. hygrophilus and P. oligospermus of the section Brevilegumeni to which it may belong. [ABSTRACT FROM AUTHOR]

This work is the validation of a bean species, Phaseolus lignosus Britton, endemic to the Bermuda archipelago. The plant grown out in Colombia from original seed collected on Long Island, Bermuda, matches with the original description. Its morphological characteristics of vegetative parts, raceme, flower and pod, being complete all suggest an affiliation with section Paniculati of this genus. An epitype has been designated and distributed since any reference plant material was missing. [ABSTRACT FROM AUTHOR]

Chloroplast DNA polymorphisms were studied by PCR sequencing and PCR-restriction fragment length polymorphism in 165 accessions of domesticated landraces of common bean from Latin America and the USA, 23 accessions of weedy beans, and 134 accessions of wild beans covering the entire geographic range of wildPhaseolus vulgaris. Fourteen chloroplast haplotypes were identified in wild beans, only five of which occur also in domesticated beans. The chloroplast data agree with those obtained from analyses based on morphology and isozymes and with other DNA polymorphisms in supporting independent domestications of common bean in Mesoamerica and the Andean region and in demonstrating a founder effect associated with domestication in each region. Andean landraces have been classified into three different racial groups, but all share the same chloroplast haplotype. This suggests that common bean was domesticated once only in South America and that the races diverged post-domestication. The haplotype found in Andean domesticated beans is confined to the southern part of the range of wild beans, so Andean beans were probably domesticated somewhere within this area. Mesoamerican landraces have been classified into four racial groups. Our limited samples of Races Jalisco and Guatemala differ from the more widespread and commercially important Races Mesoamerica and Durango in types and/or frequencies of haplotypes. All four Mesoamerican races share their haplotypes with local wild beans in parts of their ranges. Independent domestications of at least some of the races in Mesoamerica and/or conversion of some locally adapted wild beans to cultigens by hybridization with introduced domesticated beans, followed by introgression of the “domestication syndrome” seem the most plausible explanations of the chloroplast and other molecular data. [ABSTRACT FROM AUTHOR]

The genetic variability of seven Phaseolus taxa has been evaluated on the basis of molecular data and the results have used to clarify the phyletic relationships between several taxa of the P. coccineus L. complex. Chloroplast DNA (cpDNA) from 33 populations was digested with six restriction endonucleases, revealing some polymorphisms that made it possible to divide most of the taxa into two main groups: the subspecies of P. coccineus on the one hand, and P. vulgaris L., P. polyanthus Greenman and P. costaricensis (Freytag and Debouck) on the other hand. P. polyanthus is closer to P. vulgaris than the other taxa of the second group and should be considered as a separate species. The position of the wild species P. costaricensis is intermediate between P. coccineus and P. polyanthus. P. glabellus shows sufficient polymorphisms at the cpDNA level to be recognized as a separate species, as previously suggested from total seed-protein electrophoretic studies. These results favour the hypothesis of a common phylogeny for P. vulgaris, P. polyanthus, P. costaricensis and P. coccineus from a single wild ancestor. Although cpDNA is generally known to be uniform at the intraspecific level, some additional polymorphisms were also detected within P. vulgaris, P. polyanthus and P. coccineus. Further studies are required to understand the significance of the latter. [ABSTRACT FROM AUTHOR]

The article presents observations on the origin of Phaseolus polyanthus Greenman.

The CGIAR crop improvement (CI) programs, unlike commercial CI programs, which are mainly geared to profit though meeting farmers' needs, are charged with meeting multiple objectives with target populations that include both farmers and the community at large. We compiled the opinions from >30 experts in the private and public sector on key strategies, methodologies, and activities that could the help CGIAR meet the challenges of providing farmers with improved varieties while simultaneously meeting the goals of: (i) nutrition, health, and food security; (ii) poverty reduction, livelihoods, and jobs; (iii) gender equality, youth, and inclusion; (iv) climate adaptation and mitigation; and (v) environmental health and biodiversity. We review the crop improvement processes starting with crop choice, moving through to breeding objectives, production of potential new varieties, selection, and finally adoption by farmers. The importance of multidisciplinary teams working towards common objectives is stressed as a key factor to success. The role of the distinct disciplines, actors, and their interactions throughout the process from crop choice through to adoption by farmers is discussed and illustrated., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Society for Experimental Biology.)

Lima bean, Phaseolus lunatus , is a crop legume that produces the cyanogenic glucosides linamarin and lotaustralin. In the legumes Lotus japonicus and Trifolium repens , the biosynthesis of these two α-hydroxynitrile glucosides involves cytochrome P450 enzymes of the CYP79 and CYP736 families and a UDP-glucosyltransferase. Here, we identify CYP79D71 as the first enzyme of the pathway in P. lunatus , producing oximes from valine and isoleucine. A second CYP79 family member, CYP79D72, was shown to catalyze the formation of leucine-derived oximes, which act as volatile defense compounds in Phaseolus spp. The organization of the biosynthetic genes for cyanogenic glucosides in a gene cluster aided their identification in L. japonicus . In the available genome sequence of P. vulgaris , the gene orthologous to CYP79D71 is adjacent to a member of the CYP83 family. Although P. vulgaris is not cyanogenic, it does produce oximes as volatile defense compounds. We cloned the genes encoding two CYP83s (CYP83E46 and CYP83E47) and a UDP-glucosyltransferase (UGT85K31) from P. lunatus , and these genes combined form a complete biosynthetic pathway for linamarin and lotaustralin in Lima bean. Within the genus Phaseolus , the occurrence of linamarin and lotaustralin as functional chemical defense compounds appears restricted to species belonging to the closely related Polystachios and Lunatus groups. A preexisting ability to produce volatile oximes and nitriles likely facilitated evolution of cyanogenesis within the Phaseolus genus., Competing Interests: The authors declare no conflict of interest associated with the work described in this manuscript., (© 2020 The Authors. Plant Direct published by American Society of Plant Biologists, Society for Experimental Biology and John Wiley & Sons Ltd.)

The B4 resistance (R) gene cluster is one of the largest clusters known in common bean (Phaseolus vulgaris [Pv]). It is located in a peculiar genomic environment in the subtelomeric region of the short arm of chromosome 4, adjacent to two heterochromatic blocks (knobs). We sequenced 650 kb spanning this locus and annotated 97 genes, 26 of which correspond to Coiled-Coil-Nucleotide-Binding-Site-Leucine-Rich-Repeat (CNL). Conserved microsynteny was observed between the Pv B4 locus and corresponding regions of Medicago truncatula and Lotus japonicus in chromosomes Mt6 and Lj2, respectively. The notable exception was the CNL sequences, which were completely absent in these regions. The origin of the Pv B4-CNL sequences was investigated through phylogenetic analysis, which reveals that, in the Pv genome, paralogous CNL genes are shared among nonhomologous chromosomes (4 and 11). Together, our results suggest that Pv B4-CNL was derived from CNL sequences from another cluster, the Co-2 cluster, through an ectopic recombination event. Integration of the soybean (Glycine max) genome data enables us to date more precisely this event and also to infer that a single CNL moved from the Co-2 to the B4 cluster. Moreover, we identified a new 528-bp satellite repeat, referred to as khipu, specific to the Phaseolus genus, present both between B4-CNL sequences and in the two knobs identified at the B4 R gene cluster. The khipu repeat is present on most chromosomal termini, indicating the existence of frequent ectopic recombination events in Pv subtelomeric regions. Our results highlight the importance of ectopic recombination in R gene evolution.

From a phylogenetic perspective, the genus Manihot can be considered as an orphan group of plants, and the scientific knowledge acquired has been mainly related to cassava, one of the most important crops in poor tropical countries. The goal of the majority of evolutionary studies in the genus has been to decipher the domestication process and identify the closest relatives of cassava. Few investigations have focused on wild Manihot species, and the phylogeny of the genus is still unclear. In this study the DNA sequence variation from two chloroplast regions, the nuclear DNA gene G3pdh and two nuclear sequences derived from the 3'-end of two cassava ESTs, were used in order to infer the phylogenetic relationships among a subset of wild Manihot species, including two species from Cnidoscolus as out-groups. Maximum parsimony and Bayesian analyses were conducted for each data set and for a combined matrix due to the low variation of each region when analyzed independently. A penalized likelihood analysis of the chloroplast region trnL-trnF, calibrated with various age estimates for genera in the Euphorbiaceae extracted from the literature was used to determine the ages of origin and diversification of the genus. The two Mesoamerican species sampled form a well-defined clade. The South American species can be grouped into clades of varying size, but the relationships amongst them cannot be established with the data available. The age of the crown node of Manihot was estimated at 6.6 million years ago. Manihot esculenta varieties do not form a monophyletic group that is consistent with the possibility of multiple introgressions of genes from other wild species. The low levels of variation observed in the DNA regions sampled suggest a recent and explosive diversification of the genus, which is confirmed by our age estimates.