Inheritance of gene expression throughout fruit development in chili pepper

Gene expression is the primary molecular phenotype and can be estimated in specific organs or tissues at particular times. Here we analyzed genome-wide inheritance of gene expression in fruits of chili pepper (Capsicum annuum L.) in reciprocal crosses between a domesticated and a wild accession, estimating this parameter during fruit development. We defined a general hierarchical schema to classify gene expression inheritance which can be employed for any quantitative trait. We found that inheritance of gene expression is affected by both, the time of fruit development as well as the direction of the cross, and propose that such variations could be common in many developmental processes. We conclude that classification of inheritance patterns is important to have a better understanding of the mechanisms underlying gene expression regulation, and demonstrate that sets of genes with specific inheritance pattern at particular times of fruit development are enriched in different biological processes, molecular functions and cell components. All curated data and functions for analysis and visualization are publicly available as an R package.

Utilization of Tomato Landraces to Improve Seedling Performance under Salt Stress

Salt stress is considered as one of the most frequent factors limiting plant growth and productivity of crops worldwide. The aim of the study was to evaluate physiological and biochemical responses of nine diverse tomato genotypes exposed to salt stress. In this regard, four-week-old seedlings of one modern variety, five landraces, the salt-sensitive accession of ‘Ailsa Craig’, the salt-tolerant wild accession of S. pimpinellifolium ‘LA1579’, as well as the vitamin C-rich S. pennellii introgression line ‘IL12-4’, were exposed to moderate salt stress (200 mM NaCl) for 10 days. At the end of the stress treatment, agronomical traits and stress indices were evaluated, while gas exchange-related parameters, root electrolyte leakage, malondialdehyde content and ascorbic acid were also determined. All parameters were significantly affected by salt stress, but to a different extent, verifying the diverse degree of tolerance within the selected genotypes, and further highlighting the different stress-induced mechanisms. The landrace originated from ‘Santorini’ island, as well as the modern variety, which originated from traditional cultivars, demonstrated a better performance and adaptivity under moderate salt stress, accompanied by reduced lipid peroxidation and enhanced ascorbic acid content, indicating that they could be potential promising genetic material for breeding programs or as grafting rootstocks/scions.

Legacy genetics of Arachis cardenasii in the peanut crop shows the profound benefits of international seed exchange

The narrow genetics of most crops is a fundamental vulnerability to food security. This makes wild crop relatives a strategic resource of genetic diversity that can be used for crop improvement and adaptation to new agricultural challenges. Here, we uncover the contribution of one wild species accession, Arachis cardenasii GKP 10017, to the peanut crop (Arachis hypogaea) that was initiated by complex hybridizations in the 1960s and propagated by international seed exchange. However, until this study, the global scale of the dispersal of genetic contributions from this wild accession had been obscured by the multiple germplasm transfers, breeding cycles, and unrecorded genetic mixing between lineages that had occurred over the years. By genetic analysis and pedigree research, we identified A. cardenasii–enhanced, disease-resistant cultivars in Africa, Asia, Oceania, and the Americas. These cultivars provide widespread improved food security and environmental and economic benefits. This study emphasizes the importance of wild species and collaborative networks of international expertise for crop improvement. However, it also highlights the consequences of the implementation of a patchwork of restrictive national laws and sea changes in attitudes regarding germplasm that followed in the wake of the Convention on Biological Diversity. Today, the botanical collections and multiple seed exchanges which enable benefits such as those revealed by this study are drastically reduced. The research reported here underscores the vital importance of ready access to germplasm in ensuring long-term world food security.

Identification of barley genetic regions influencing plant–microbe interactions and carbon cycling in soil

Purpose Rhizodeposition shapes soil microbial communities that perform important processes such as soil C mineralization, but we have limited understanding of the plant genetic regions influencing soil microbes. Here, barley chromosome regions affecting soil microbial biomass-C (MBC), dissolved organic-C (DOC) and root biomass were characterised. Methods A quantitative trait loci analysis approach was applied to identify barley chromosome regions affecting soil MBC, soil DOC and root biomass. This was done using barley Recombinant Chromosome Substitution Lines (RCSLs) developed with a wild accession (Caesarea 26-24) as a donor parent and an elite cultivar (Harrington) as recipient parent. Results Significant differences in root-derived MBC and DOC and root biomass among these RCSLs were observed. Analysis of variance using single nucleotide polymorphisms genotype classes revealed 16 chromosome regions influencing root-derived MBC and DOC. Of these chromosome regions, five on chromosomes 2H, 3H and 7H were highly significant and two on chromosome 3H influenced both root-derived MBC and DOC. Potential candidate genes influencing root-derived MBC and DOC concentrations in soil were identified. Conclusion The present findings provide new insights into the barley genetic influence on soil microbial communities. Further work to verify these barley chromosome regions and candidate genes could promote marker assisted selection and breeding of barley varieties that are able to more effectively shape soil microbes and soil processes via rhizodeposition, supporting sustainable crop production systems.

Identification of Gray Leaf Spot Disease Candidate Gene in Narrow-Leafed Lupin (Lupinus angustifolius L.)

Selection for resistance against gray leaf spot (GLS) is a major objective in the lupin breeding programs. A segregation ratio of 1:1 (resistant:susceptible) in F8 recombinant inbred lines (RIL8) derived from a cross between a breeding line 83A:476 (resistant to GLS) and a wild accession P27255 (susceptible to GLS) indicated that GLS was controlled by a single major gene. To develop molecular markers linked to GLS, in the beginning, only 11 resistant lines and six susceptible lines from the 83A:476 and P27255 population were genotyped with MFLP markers, and three MFLP markers were identified to be co-segregated with GLS. This method was very efficient, but the markers were located outside of the gene, and could not be used in other germplasms. Then QTL analysis and fine mapping were conducted to identify the gene. Finally, the gene was narrowed down to a 241-kb region containing two disease resistance genes. To further identify the candidate gene, DNA variants between accessions Tanjil (resistant to GLS) and Unicrop (susceptible to GLS) were analyzed. The results indicated that only one SNP was detected in the 241 kb region. This SNP was located in the TMV resistance protein N-like gene region and also identified between 83A:476 and P27255. Genotyping the Tanjil/Unicrop RIL8 population showed that this SNP co-segregated with GLS resistance. The phylogenetic tree analysis of this gene among 18 lupin accessions indicates that Australian resistant breeding line/varieties were clustered into one group and carry two resistant alleles, while susceptible accessions were clustered into different groups.

Domestication of Chili Pepper Has Altered Fruit Traits Affecting the Oviposition and Feeding Behavior of the Pepper Weevil

The pepper weevil, Anthonomus eugenii, Cano (Coleoptera: Curculionidae), is one of the most destructive pests of chili pepper. It causes extensive damage on varieties selected for consumption. However, the occurrence of this pest on wild and ornamental peppers remains unknown. We investigated the consequences of chili domestication on the feeding and oviposition of A. eugenii on fruits and flowers. We used plants of one wild accession, Bird Eye Pepper, five ornamental varieties (Pops Yellow, Black Pearl, Sedona Sun, Chilli Chilli, and Salsa Deep), and two domesticated varieties selected for consumption (Scotch Bonnet and Jalapeño). First, we characterized the plants according to their fruit and flower sizes, pericarp thickness, capsaicin level, fruit position, and flower color. Then, we evaluated the susceptibility of fruits and flowers to A. eugenii. Overall, domestication increased fruit and flower sizes and pericarp thickness, altered capsaicin levels, and altered fruit position and flower color. Weevils laid more eggs and caused more feeding damage on varieties selected for consumption than on wild and ornamental plants. Our results add to the growing literature on the consequences of crop domestication on herbivores. This knowledge could be integrated into breeding programs to select varieties resistant against the pepper weevil.

Cloning, expression and characterization of arcelin and its impact on digestive enzymes of the stored product insect pest, Callosobruchus maculatus (F.)

Key message The defensive role of arcelin from Phaseolus lunatus for its protection against insect pest Callosobruchus maculatus was elucidated. The potent insecticidal property of arcelin and its impact on pest molecular physiology has identified the adaptive strategies. Abstract The pulse beetle Callosobruchus maculatus causes potential damage to legume crops by infesting the seeds and causes a reduction in the content of total protein. Arcelin found in the wild accessions of the common bean, is an insecticidal protein that has the potency to hamper the metabolism of the bruchid beetle. The arcelin gene from the wild accession of Phaseolus lunatus was isolated and the ORF encoding 158 amino acids was cloned in pET-45b (+) vector. The recombinant was transformed into BL21 STAR (DE3) pLysS cells, and the expressed arcelin was purified using Ni-NTA column. The recombinant protein was used in preparing artificial diet and the insecticidal activity was elucidated against the bruchid pest C. maculatus. Adult emergence and seed damage were drastically reduced in the treated groups. The response towards ingested diet by digested enzymes was elucidated through quantitative gene expression. Maximum expression was observed in the aminopeptidase, followed by upregulation of alpha-amylase, glycoside hydrolase family 31 and cathepsin D-like aspartic protease, and downregulation of cathepsin L-like cysteine protease. These results showed the anti-metabolic nature of the recombinant arcelin. The changes in digestive enzymes to counteract the anti-nutritional nature of the protein were the strategies of the insect defense mechanism.

Comparing Wild and Cultivated Arnica montana L. from the Italian Alps to Explore the Possibility of Sustainable Production Using Local Seeds

Arnica montana L. is an alpine herbaceous plant typical of nutrient-poor grasslands. It is a popular medicinal plant for the treatment of bruises, cuts and pain, and it is also an endangered alpine species. For this reason, the sustainable production of inflorescences instead of the spontaneous collection of plant material, coupled with the use of local ecotypes, should be incentivized. Inflorescences of a wild accession of arnica were compared versus an accession cultivated in Valsaviore (Italian Alps) in terms of seed germination performance and phytochemical characterization by high performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) and gas chromatography–mass spectrometry (GC-MS) techniques. The germination percentage was high (>75%) for both cultivated and wild seeds. The NMR spectra of arnica extracts were very similar and confirmed the presence of sesquiterpene compounds, esters of helenaline and dehydroelenaline. A significant high percentage of acetic acid methyl ester (38 μg/g) and the 2-methyl methyl ester of propanoic acid (31 μg/g) were found in cultivated arnica and were probably associated with fermentation processes linked to the traditional method of air drying on a trellis. The possibility of growing A. montana and a controlled local first transformation are important to incentivize local, good quality and sustainable production. The growing of seedlings “in loco” could be of great interest both for farmers and for natural conservation purposes.

CONTENT OF PHOTOSYNTHETIC PIGMENTS IN ONTOGENESIS OF WILD AND CULTURAL PEA

The objective consisted in study of wild pea representatives on chlorophyll and carotenoid content for use in producing new varieties with high photosynthetic efficiency and optimal assimilate distribution. The research was conducted in 2016‑2017 in Federal Scientific Center of Legumes and Groat Crops (Orel). Plants were grown on experimental field with density 1.2 million plants/ha on triplicated plots 1 m2. Wild pea accessions k-5322 (asiaticum), k-3370 (elatius), k-4014 (elatius) from VIR collection and varieties Temp and Stabil were used. Wild accessions k-3370 and k-5322 had more chlorophyll a, chlorophyll b and carotenoids then leafy Temp variety on 24.5 %, 28.2 %, 41.5 % and 13.3 %, 2.7 %, 18.7 % respectively. Unlike the cultivated pea, accessions k-3370 and k-5322 retain high level of chlorophylls a and b in ontogenesis longer time. After transition from bud formation to the beginning of seed filling content of chlorophylls a and b in accession k-3370 was at the same level (11.71 mg/g и 11.1 mg/g respectively), in accession k-5322 it decreased insignificantly from 11.31 mg/g to 9.72 mg/g. Nevertheless, in variety Temp content of chlorophylls a and b significantly decreased on 34.1 % after transition from bud formation to the seed filling. Wild accession k-3370 like pea varieties had low chlorophyll a/b ratio (2.92), but accession k-5322 had the highest value (3.26) of the ratio. In wild accession k-3370 and k-5322 the chlorophyll a/b ratio was changed in ontogenesis that is no-typical for Temp variety. Pea wild accessions can be considered as sources of valuable alleles determining the high level of chlorophylls and carotenoids