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The common bean has received attention as a model plant for legume studies, but little information is available about the morphology of its pods and the relation of this morphology to the loss of seed dispersal and/or the pod string, which are key agronomic traits of legume domestication. Dehiscence is related to the pod morphology and anatomy of pod tissues because of the weakening of the dorsal and ventral dehiscence zones and the tensions of the pod walls. These tensions are produced by the differential mechanical properties of lignified and non-lignified tissues and changes in turgor associated with fruit maturation. In this research, we histologically studied the dehiscence zone of the ventral and dorsal sutures of the pod in two contrasting genotypes for the dehiscence and string, by comparing different histochemical methods with autofluorescence. We found that the secondary cell wall modifications of the ventral suture of the pod were clearly different between the dehiscence-susceptible and stringy PHA1037 and the dehiscence-resistant and stringless PHA0595 genotypes. The susceptible genotype had cells of bundle caps arranged in a more easily breakable bowtie knot shape. The resistant genotype had a larger vascular bundle area and larger fibre cap cells (FCCs), and due to their thickness, the external valve margin cells were significantly stronger than those from PHA1037. Our findings suggest that the FCC area, and the cell arrangement in the bundle cap, might be partial structures involved in the pod dehiscence of the common bean. The autofluorescence pattern at the ventral suture allowed us to quickly identify the dehiscent phenotype and gain a better understanding of cell wall tissue modifications that took place along the bean’s evolution, which had an impact on crop improvement. We report a simple autofluorescence protocol to reliably identify secondary cell wall organization and its relationship to the dehiscence and string in the common bean.

The determination of the endodormancy release and the beginning of ontogenetic development is a challenge, because these are non-observable stages. Changes in protein activity are important aspects of signal transduction. The conversion of threonine to 2-oxobutanoate is the first step towards isoleucine (Ile) biosynthesis, which promote growth and development. The reaction is catalyzed by threonine deaminase/dehydratase (TD). This study on TD activity was conducted at the experimental sweet cherry orchard at Berlin-Dahlem. Fresh (FW), dry weight (DW), water content (WC), and the specific TD activity for the cherry cultivars Summit, Karina and Regina were conducted from flower bud samples between October and April. The content of asparagine (Asn), aspartic acid (Asp), Ile, and valine (Val) were exemplarily shown for Summit. In buds of Summit and Karina, the TD activity was one week after the beginning of the ontogenetic development (t1*), significantly higher compared to samplings during endo- and ecodormancy. Such “peak” activity did not occur in the buds of Regina; TD tended for a longer time (day of year, DOY 6–48) to a higher activity, compared to the time DOY 287–350. For the date “one week after t1*”, the upregulation of TD, the markedly increase of the Ile and Val content, and the increase of the water content in the buds, all this enzymatically confirms the estimated start of the ontogenetic development (t1*) in sweet cherry buds., Peer Reviewed

The olive (Olea europaea L.) is an ancient crop of great importance in the Mediterranean basin due to the production of olive oil and table olives, which are important sources of fat and have benefits for human health. This crop is expanding and increasing its production worldwide and five olive genomes have recently been sequenced, representing a wild olive and important cultivars in terms of olive oil production, intensive agriculture, and adaptation to the East Asian climate. However, few bioinformatic and genomic resources are available to assist olive research and breeding, and there are no platforms to query olive gene expression data. Here, we present OliveAtlas, an interactive gene expression atlas for olive with multiple bioinformatics tools and visualization methods, enabling multiple gene comparison, replicate inspection, gene set enrichment, and data downloading. It contains 70 RNA-seq experiments, organized in 10 data sets representing the main olive plant organs, the pollen germination and pollen tube elongation process, and the response to a collection of biotic and abiotic stresses, among other experimental conditions. OliveAtlas is a web tool based on easyGDB with expression data based on the ‘Picual’ genome reference and gene annotation.

In recent years, novel food is becoming an emerging trend increasingly more demanding in developed countries. Food proteins from vegetables (pulses, legumes, cereals), fungi, bacteria and insects are being researched to introduce them in meat alternatives, beverages, baked products and others. One of the most complex challenges for introducing novel foods on the market is to ensure food safety. New alimentary scenarios drive the detection of novel allergens that need to be identified and quantified with the aim of appropriate labelling. Allergenic reactions are mostly caused by proteins of great abundance in foods, most frequently of small molecular mass, glycosylated, water-soluble and with high stability to proteolysis. The most relevant plant and animal food allergens, such as lipid transfer proteins, profilins, seed storage proteins, lactoglobulins, caseins, tropomyosins and parvalbumins from fruits, vegetables, nuts, milk, eggs, shellfish and fish, have been investigated. New methods for massive screening in search of potential allergens must be developed, particularly concerning protein databases and other online tools. Moreover, several bioinformatic tools based on sequence alignment, motif identification or 3-D structure predictions should be implemented as well. Finally, targeted proteomics will become a powerful technology for the quantification of these hazardous proteins. The ultimate objective is to build an effective and resilient surveillance network with this cutting-edge technology.

Plant reproduction is essential for crop seed and fruit production. In order to ensure an optimal crop yield, it is crucial to investigate the mechanisms that govern pollen germination and pollen tube growth. Post‐translational modifications (PTM) are key mechanisms for regulating gene expression and protein activity. Among them, carbonylation (i.e. the oxidation of protein side chains) is important for the correct function of cells under optimal conditions. Nevertheless, under oxidative stress, carbonylation levels tend to increase, triggered by high levels of reactive oxygen and nitrogen species (ROS and RNS, respectively), and may lead to cellular malfunction and programmed cell death. In the present work, we used an experimental proteome of olive (Olea europaea L.) pollen [1] and the predictive tools iCarPS and CarSPred to get a first approach about the susceptibility to carbonylation of c.a. 2,000 pollen proteins. An experimental profile of carbonylated proteins from pollen was also obtained after immunoprecipitation assays and further identification of carbonylated peptides and residues by LC‐ESI‐MS/MS. Our results indicated that 15% of proteins present in olive mature pollen were susceptible to carbonylation. Most of carbonylated proteins are cytoplasmatic and membrane‐bound, and participate in protein translation and lipid signaling. Considering both in silico and in vitro data from our experiments, we speculated that carbonylation forms part of a mechanism of regulation that is not only important during pollen germination and pollen tube growth but is also involved in allergy processes caused by olive pollen. According with the pattern of carbonylation that we determined, this PTM could participate in the regulation and maintenance of cell integrity during pollen tube growth within the pistil.

The pollen tube is a key innovation of land plants that is essential for successful fertilisation. Its development and growth have been profusely studied in model organisms, but in spite of the economic impact of olive trees, little is known regarding the genome-wide events underlying pollen hydration and growth in this species. To fill this gap, triplicate mRNA samples at 0, 1, 3, and 6 h of in vitro germination of olive cultivar Picual pollen were analysed by RNA-seq. A bioinformatics R workflow called RSeqFlow was developed contemplating the best practices described in the literature, covering from expression data filtering to differential expression and clustering, to finally propose hub genes. The resulting olive pollen transcriptome consisted of 22,418 reliable transcripts, where 5364 were differentially expressed, out of which 173 have no orthologue in plants and up to 3 of them might be pollen-specific transcription factors. Functional enrichment revealed a deep transcriptional reprogramming in mature olive pollen that is also dependent on protein stability and turnover to allow pollen tube emergence, with many hub genes related to heat shock proteins and F-box-containing proteins. Reprogramming extends to the first 3 h of growth, including processes consistent with studies performed in other plant species, such as global down-regulation of biosynthetic processes, vesicle/organelle trafficking and cytoskeleton remodelling. In the last stages, growth should be maintained from persistent transcripts. Mature pollen is equipped with transcripts to successfully cope with adverse environments, even though the in vitro growth seems to induce several stress responses. Finally, pollen-specific transcription factors were proposed as probable drivers of pollen germination in olive trees, which also shows an overall increased number of pollen-specific gene isoforms relative to other plants.

Pollen development is a crucial biological process indispensable for seed set in flowering plants and for successful crop breeding. However, little is known about the molecular mechanisms regulating pollen development in crop species. This study reports a novel male-sterile tomato mutant, pollen deficient 2 (pod2), characterized by the production of non-viable pollen grains and resulting in the development of small parthenocarpic fruits. A combined strategy of mapping-by-sequencing and RNA interference-mediated gene silencing was used to prove that the pod2 phenotype is caused by the loss of Solanum lycopersicum G-Type lectin receptor kinase II.9 (SlG-LecRK-II.9) activity. In situ hybridization of floral buds showed that POD2/SlG-LecRK-II.9 is specifically expressed in tapetal cells and microspores at the late tetrad stage. Accordingly, abnormalities in meiosis and tapetum programmed cell death in pod2 occurred during microsporogenesis, resulting in the formation of four dysfunctional microspores leading to an aberrant microgametogenesis process. RNA-seq analyses supported the existence of alterations at the final stage of microsporogenesis, since we found tomato deregulated genes whose counterparts in Arabidopsis are essential for the normal progression of male meiosis and cytokinesis. Collectively, our results revealed the essential role of POD2/SlG-LecRK-II.9 in regulating tomato pollen development.

Songbirds have one special accessory chromosome, the so-called germline-restricted chromosome (GRC), which is only present in germline cells and absent from all somatic tissues. Earlier work on the zebra finch (Taeniopygia guttata castanotis) showed that the GRC is inherited only through the female line-like the mitochondria-and is eliminated from the sperm during spermatogenesis. Here, we show that the GRC has the potential to be paternally inherited. Confocal microscopy using GRC-specific fluorescent in situ hybridization probes indicated that a considerable fraction of sperm heads (1 to 19%) in zebra finch ejaculates still contained the GRC. In line with these cytogenetic data, sequencing of ejaculates revealed that individual males from two families differed strongly and consistently in the number of GRCs in their ejaculates. Examining a captive-bred male hybrid of the two zebra finch subspecies (T. g. guttata and T. g. castanotis) revealed that the mitochondria originated from a castanotis mother, whereas the GRC came from a guttata father. Moreover, analyzing GRC haplotypes across nine castanotis matrilines, estimated to have diverged for up to 250,000 y, showed surprisingly little variability among GRCs. This suggests that a single GRC haplotype has spread relatively recently across all examined matrilines. A few diagnostic GRC mutations that arose since this inferred spreading suggest that the GRC has continued to jump across matriline boundaries. Our findings raise the possibility that certain GRC haplotypes could selfishly spread through the population via occasional paternal transmission, thereby out-competing other GRC haplotypes that were limited to strict maternal inheritance, even if this was partly detrimental to organismal fitness.

Yellow lupine is an economically important crop. This species has been used as a great model for abscission processes for several years due to extreme flower abortion, which takes place in the abscission zone (AZ). AZ activation involves modifications of cell walls, membranes, and cellular structure. In this paper, we applied physiological, molecular, biochemical, and instrumental methods to explore lipid-associated changes and the possible involvement of lipid-derived phytohormones – jasmonates (JAs) - in flower AZ activation. Our comprehensive analyses revealed that natural abscission is accompanied by the upregulation of peroxidase, which reflects a disruption of redox balance and/or lipids peroxidation in AZ cell membranes. Redox imbalance was confirmed by appearance of malondialdehyde. Lipid-related processes involved the specific localization and increased level and activity of lipase and LOX, enzymes associated with cell membrane rupture, and JA biosynthesis. Lipid-hydrolyzing phospholipase D, implicated previously in abscission, is also found in naturally active AZs. Observed changes are accompanied by the accumulation of jasmonates, both free jasmonic acid and its methyl ester. The JA derivative exhibited higher biological activity than the nonconjugated form. Overall, our study shed new light on the lipid and phytohormonal regulation of AZ functioning supporting a role of JAs during abscission-associated events.

We recently showed that yellow lupine is highly sensitive to soil water deficits since this stressor disrupts nodule structure and functioning, and at the same time triggers flower separation through abscission zone (AZ) activation in the upper part of the plant. Both processes require specific transformations including cell wall remodeling. However, knowledge about the involvement of particular cell wall elements in nodulation and abscission in agronomically important, nitrogen‐fixing crops, especially under stressful conditions, is still scarce. Here, we used immuno‐fluorescence techniques to visualize dynamic changes in cell wall compounds taking place in the root nodules and flower AZ of Lupinus luteus following drought. The reaction of nodules and the flower AZ to drought includes the upregulation of extensins, galactans, arabinans, xylogalacturonan, and xyloglucans. Additionally, modifications in the localization of high‐ and low‐methylated homogalacturonans and arabinogalactan proteins were detected in nodules. Collectively, we determined for the first time the drought‐associated modification of cell wall components responsible for their remodeling in root nodules and the flower AZ of L. luteus. The involvement of these particular molecules and their possible interaction in response to stress is also deeply discussed herein.