Angular leaf spot (ALS) is a disease that causes major yield losses in the common bean crop. Studies based on different isolates and populations have already been carried out to elucidate the genetic mechanisms of resistance to ALS. However, understanding of the interaction of this resistance with the reproductive stages of common bean is lacking. The aim of the present study was to identify ALS resistance loci at different plant growth stages (PGS) by association and linkage mapping approaches. An BC2F3 inter-gene pool cross population (AND 277 × IAC-Milênio – AM population) profiled with 1,091 SNPs from genotyping by sequencing (GBS) was used for linkage mapping, and a carioca diversity panel (CDP) genotyped by 5,398 SNPs from BeadChip assay technology was used for association mapping. Both populations were evaluated for ALS resistance at the V2 and V3 PGSs (controlled conditions) and R8 PGS (field conditions). Different QTL (quantitative trait loci) were detected for the three PGSs and both populations, showing a different quantitative profile of the disease at different plant growth stages. For the three PGS, multiple interval mapping (MIM) identified seven significant QTL, and the Genome-wide association study (GWAS) identified fourteen associate SNPs. Several loci validated regions of previous studies, and Phg-1, Phg-2, Phg-4, and Phg-5, among the 5 loci of greatest effects reported in the literature, were detected in the CDP. The AND 277 cultivar contained both the Phg-1 and the Phg-5 QTL, which is reported for the first time in the descendant cultivar CAL143 as ALS10.1UC. The novel QTL named ALS11.1AM was located at the beginning of chromosome Pv11. Gene annotation revealed several putative resistance genes involved in the ALS response at the three PGSs, and with the markers and loci identified, new specific molecular markers can be developed, representing a powerful tool for common bean crop improvement and for gain in ALS resistance.

Background Common bean (Phaseolus vulgaris L.) is a legume whose grain can be stored for months, a common practice among Brazilian growers. Over time, seed coats become darker and harder to cook, traits that are undesirable to consumers, who associate darker-colored beans with greater age. Like commercial pinto and cranberry bean varieties, carioca beans that have darker seeds at harvest time and after storage are subject to decreased market values. Results The goal of our study was to identify the genetic control associated with lightness of seed coat color at harvest (HL) and with tolerance to post-harvest seed coat darkening (PHD) by a genome-wide association study. For that purpose, a carioca diversity panel previously validated for association mapping studies was used with 138 genotypes and 1,516 high-quality SNPs. The panel was evaluated in two environments using a colorimeter and the CIELAB scale. Shelf storage for 30 days had the most expressive results and the L* (luminosity) parameter led to the greatest discrimination of genotypes. Three QTL were identified for HL, two on chromosome Pv04 and one on Pv10. Regarding PHD, results showed that genetic control differs for L* after 30 days and for the ΔL* (final L*—initial L*); only ΔL* was able to properly express the PHD trait. Four phenotypic classes were proposed, and five QTL were identified through six significant SNPs. Conclusions Lightness of seed coat color at harvest showed an oligogenic inheritance corroborated by moderate broad-sense heritability and high genotypic correlation among the experiments. Only three QTL were significant for this trait – two were mapped on Pv04 and one on Pv10. Considering the ΔL, six QTL were mapped on four different chromosomes for PHD. The same HL QTL at the beginning of Pv10 was also associated with ΔL* and could be used as a tool in marker-assisted selection. Several candidate genes were identified and may be useful to accelerate the genetic breeding process.

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The use of UV-C cool white light on bean (Phaseolus vulgaris L.) seeds significantly increases the biochemical seed coat post-harvest darkening process, whilst preserving seed germination. The aim of this work consists in monitoring the effect caused by the incidence of UV-C light on different bean genotypes using NMR spectroscopy. The genotype samples named IAC Alvorada; TAA Dama; BRS Estilo and BRS Pérola from the Agronomic Institute (IAC; Campinas; SP; Brazil) were evaluated. The following two methodologies were used: a prolonged darkening, in which the grain is placed in a room at a controlled temperature (298 K) and humidity for 90 days, simulating the supermarket shelf; an accelerated darkening, where the grains are exposed to UV-C light (254 nm) for 96 h. The experiments were performed using the following innovative time-domain (TD) NMR approaches: the RK-ROSE pulse sequence; one- and two-dimensional high resolution (HR) NMR experiments (1H; 1H-1H COSY and 1H-13C HSQC); chemometrics tools, such as PLS-DA and heat plots. The results suggest that the observed darkening occurs on the tegument after prolonged (90 days) and accelerated (96 h) conditions. In addition, the results indicate that phenylalanine is the relevant metabolite within this context, being able to participate in the chemical reactions accounted for by the darkening processes. Additionally, it is possible to confirm that a UV-C lamp accelerates oxidative enzymatic reactions and that the NMR methods used were a trustworthy approach to monitor and understand the darkening in bean seeds at metabolite level.

Common bean is a worldwide important crop. The development of varieties with durable resistance to diseases is a major challenge in common bean breeding. The present study aimed at evaluating the phenotypic and molecular selection of anthracnose resistance in a population obtained by assisted backcrossing from IAC Formoso (resistant, donor parent) × BRS Pérola (susceptible, recurrent parent). Nine microsatellites (SSRs) and one Sequence Tagged Sites (STS) markers previously linked to ANT resistance were used to genotype this progeny, and the results showed that the selection of the genotypes closest to the donor parent in the BC 1 F 1 population decreased the number of backcrossing cycles necessary to obtain advanced isogenic lines, potentiating the use of this tool for early selection of resistant cultivars. A total of 31 % of the BC 1 F 1 progeny was selected and backcrossed again. The progeny derived from the second backcross (BC 2 F 3 ) was selected for the Carioca grain ideotype, and 42 % of the genotypes showed high resistance to anthracnose under controlled conditions of infection for races 65 and 81. Superior resistant plants were selected and evaluated under natural conditions of infection to fusarium wilt and angular leaf spot, allowing the selection of two inbred lines with higher resistance to anthracnose, fusarium wilt, angular leaf spot and postharvest quality traits such as yield, 100 seed weight, L value at seed harvest grain darkening and cooking time.The approach outlined in this paper proved to be effective to simultaneously select for disease resistance without losing technological quality aspects of the bean.

Angular leaf spot, a disease caused by the fungus Pseudocercospora griseola, can lead to yield losses of up to 70% in the common bean (Phaseolus vulgaris) crop. Due to the quantitative character of angular leaf spot, a cultivar with high resistance depends on the presence of several resistance loci. In the present study, a markerassisted backcrossing approach was used involving an Andean donor parent (AND 277) and a Mesoamerican recurrent parent (IAC-Milênio). For marker-assisted backcrossing in the BC 1 F 1 genotypes, 15 molecular markers previously mapped for angular leaf spot resistance loci were used, and selection was performed by genotypes grouped with the donor parent in discrimination analysis of principal components. Through molecular selection, 42% of the BC 2 F 3 families selected for the Carioca grain ideotype showed high resistance to angular leaf spot under controlled conditions of infection. Two lines resistant under natural conditions and tolerant to Fusarium wilt (Fusarium oxysporum f. sp. phaseoli J. B. Kendr. & W. C. Snyder) were selected for the competition trial. The lines selected, AM138 and AM167, showed superiority to the recurrent cultivar for six of the eight agronomic traits, including resistance to Race 65 of Colletotrichum lindemuthianum slow grain darkening, early maturity, and lighter grain color. Both advanced lines will be included in the value for cultivation and use trials; and as Carioca lines with resistance of Andean origin, they can be widely used as sources of resistance in breeding programs to overcome problems related to inter-gene pool crosses.

Este projeto objetiva desenvolver linhagens industriais de S. cerevisiae termotolerantes atráves da metodologia de engenharia evolutiva, visando selecionar linhagens mais adaptadas às condições de hidrólise (temperatura igual ou superior à 40ºC) para aplicação na produção de etanol lignocelulósico mediante o processo de Sacarificação e Fermentação Simultânea (SSF).

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