Identification of Novel Sources of Resistance to Seed Weevils (Bruchus spp.) in a Faba Bean Germplasm Collection

Seed weevils (Bruchus spp.) are major pests of faba bean, causing yield losses, and affecting marketability. Our objective was to identify stable sources of resistance to seed weevil attacks, determine the climatic factors that most influenced its incidence and its relationship with some phenological and agronomic traits. The accessions "BOBICK ROD115," "CÔTE D'OR," "221516," and "NOVA GRADISKA" showed increased resistance to penetration and development of larvae. Other accessions such as "QUASAR," "109.669," and "223303" exhibited resistance to larval development. The results of this work suggest the presence of different defense mechanisms to seed weevils in faba bean, which in the future could be introgressed in elite cultivars to create resistant varieties and contribute to more sustainable agriculture with less need for pesticides. The temperature, rainfall, and humidity seemed to be the climatic factors most influencing faba bean seed weevil attack while the precocity and the small weight of the seeds were correlated with lower infestation rates in the different experiments.

Root traits of European Vicia faba cultivars-Using machine learning to explore adaptations to agroclimatic conditions

Faba bean (Vicia faba L.) is an important source of protein, but breeding for increased yield stability and stress tolerance is hampered by the scarcity of phenotyping information. Because comparisons of cultivars adapted to different agroclimatic zones improve our understanding of stress tolerance mechanisms, the root architecture and morphology of 16 European faba bean cultivars were studied at maturity. Different machine learning (ML) approaches were tested in their usefulness to analyse trait variations between cultivars. A supervised, that is, hypothesis-driven, ML approach revealed that cultivars from Portugal feature greater and coarser but less frequent lateral roots at the top of the taproot, potentially enhancing water uptake from deeper soil horizons. Unsupervised clustering revealed that trait differences between northern and southern cultivars are not predominant but that two cultivar groups, independently from major and minor types, differ largely in overall root system size. Methodological guidelines on how to use powerful ML methods such as random forest models for enhancing the phenotypical exploration of plants are given.

Genome-Wide Identification of bZIP Transcription Factors in Faba Bean Based on Transcriptome Analysis and Investigation of Their Function in Drought Response

Faba bean is an important cool-season edible legume crop that is constantly threatened by abiotic stresses such as drought. The basic leucine zipper (bZIP) gene family is one of the most abundant and diverse families of transcription factors in plants. It regulates plant growth and development and plays an important role in the response to biotic and abiotic stresses. In this study, we identified 18 members of the faba bean bZIP transcription factor family at the genome-wide level based on previous faba bean drought stress transcriptome sequencing data. A phylogenetic tree was constructed to group the 18 VfbZIP proteins into eight clades. Analysis of cis-acting elements in the promoter region suggested that these 18 VfbZIPs may be involved in regulating abiotic stress responses such as drought. Transcriptome data showed high expression of seven genes (VfbZIP1, VfbZIP2, VfbZIP5, VfbZIP7, VfbZIP15, VfbZIP17, and VfbZIP18) in the drought-tolerant cultivar under drought stress, in which VfbZIP1, VfbZIP2, and VfbZIP5 were consistently expressed as detected by quantitative real-time polymerase chain reaction (qRT-PCR) compared to the transcriptome data. Ectopic overexpression of the three VfbZIPs in tobacco, based on the potato Virus X (PVX) vector, revealed that VfbZIP5 enhanced the drought tolerance. Overexpressed VfbZIP5 in plants showed lower levels of proline (PRO), malondialdehyde (MDA), and peroxidase (POD) compared to those overexpressing an empty vector under 10 days of drought stress. Protein-protein interaction (PPI) analysis showed that VfbZIP5 interacted with seven proteins in faba bean, including VfbZIP7 and VfbZIP10. The results depict the importance of VfbZIPs in response to drought stress, and they would be useful for the improvement of drought tolerance.

Using vibrational molecular spectroscopy to reveal carbohydrate molecular structure properties of faba bean partitions and faba bean silage before and after rumen incubation in relation to nutrient availability and supply to dairy cattle

To our knowledge, there is limited study on the relationship between the molecular structure of feed and nutrient availability in the ruminant system. The objective of this study is to use advanced vibrational molecular spectroscopy (attenuated total reflection [ATR]-Fourier transform infrared [FT/IR]) to reveal carbohydrate molecular structure properties of faba bean partitions (stem, leaf, whole pods [WP], and whole plant) and faba bean silage before and after rumen incubation in relation to nutrient availability and supply to dairy cattle. The study included the correlation between carbohydrate-related spectral profiles and chemical profiles, feed energy values, Cornell Net Carbohydrate and Protein System carbohydrate fractions, and rumen degradation parameters of faba bean samples (whole crop, stem, leaf, WP, and silage) before and after rumen incubation. FTIR spectra of faba bean sample before and after 12 and 24 h rumen incubations were collected with JASCO FT/IR-4200 with ATR at mid-IR range (ca. 4000-700 cm^-1 ) with 128 scans and at 4 cm^-1 resolution. The univariate molecular spectral analysis was carried out using OMNIC software. The results show that ATR-FT/IR spectroscopic technique could detect the change of microbial digestion to carbohydrate-related molecular structure. The spectral parameters of feed rumen incubation residues had a stronger correlation with less degradable carbohydrate fractions (neutral detergent fiber, acid detergent fiber, acid detergent lignin, hemicellulose, and cellulose) while spectral profiles of original faba samples had a stronger correlation with easily degradable carbohydrate fractions (starch). In conclusion, rumen degradation of carbohydrate contents can be reflected in the change of its molecular spectral profiles. The study shows that vibrational molecular spectroscopy (ATR-FT/IR) shows high potential as a fast analytical tool to evaluate and predict nutrient supply in the ruminant system.

A QTL approach in faba bean highlights the conservation of genetic control of frost tolerance among legume species

Frost is a major abiotic stress of winter type faba beans (Vica faba L.) and has adverse effects on crop yield. Climate change, far from reducing the incidence of frost events, is making these phenomena more and more common, severe, and prolonged. Despite the important interaction that the environment has in the tolerance of faba bean to frost, this trait seems to have good levels of heritability. Several QTLs for frost tolerance have already been reported, however, a more robust identification is needed to more precisely identify the genomic regions involved in faba bean tolerance to sub-zero temperatures. Several pea (Pisum sativum L.) and barrel medic (Medicago truncatula L.) frost tolerance QTLs appear to be conserved between these two species, furthering the hypothesis that the genetic control of frost tolerance in legume species might be more generally conserved. In this work, the QTL mapping in two faba bean recombinant inbred line (RIL) populations connected by a common winter-type parent has led to the identification of five genomic regions involved in the control of frost tolerance on linkage groups I, III, IV, and V. Among them, a major and robust QTL of great interest for marker-assisted selection was identified on the lower part of the long-arm of LGI. The synteny between the faba bean frost tolerance QTLs and those previously identified in other legume species such as barrel medic, pea or soybean highlighted at least partial conservation of the genetic control of frost tolerance among different faba bean genetic pools and legume species. Four novel RILs showing high and stable levels of tolerance and the ability to recover from freezing temperatures by accumulating frost tolerance QTLs are now available for breeding programs.