Regulation of Zn and Fe transporters by the GPC1 gene during early wheat monocarpic senescence

BACKGROUND: During wheat senescence, leaf components are degraded in a coordinated manner, releasing amino acids and micronutrients which are subsequently transported to the developing grain. We have previously shown that the simultaneous downregulation of Grain Protein Content (GPC) transcription factors, GPC1 and GPC2, greatly delays senescence and disrupts nutrient remobilization, and therefore provide a valuable entry point to identify genes involved in micronutrient transport to the wheat grain. RESULTS: We generated loss-of-function mutations for GPC1 and GPC2 in tetraploid wheat and showed in field trials that gpc1 mutants exhibit significant delays in senescence and reductions in grain Zn and Fe content, but that mutations in GPC2 had no significant effect on these traits. An RNA-seq study of these mutants at different time points showed a larger proportion of senescence-regulated genes among the GPC1 (64%) than among the GPC2 (37%) regulated genes. Combined, the two GPC genes regulate a subset (21.2%) of the senescence-regulated genes, 76.1% of which are upregulated at 12 days after anthesis, before the appearance of any visible signs of senescence. Taken together, these results demonstrate that GPC1 is a key regulator of nutrient remobilization which acts predominantly during the early stages of senescence. Genes upregulated at this stage include transporters from the ZIP and YSL gene families, which facilitate Zn and Fe export from the cytoplasm to the phloem, and genes involved in the biosynthesis of chelators that facilitate the phloem-based transport of these nutrients to the grains. CONCLUSIONS: This study provides an overview of the transport mechanisms activated in the wheat flag leaf during monocarpic senescence. It also identifies promising targets to improve nutrient remobilization to the wheat grain, which can help mitigate Zn and Fe deficiencies that afflict many regions of the developing world.Fil: Pearce, Stephen. University of California; Estados UnidosFil: Tabbita, Facundo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Cantu, Dario. University of California; Estados UnidosFil: Buffalo, Vince. University of California; Estados UnidosFil: Avni, Raz. Tel Aviv University; IsraelFil: Vazquez Gross, Hans. University of California; Estados UnidosFil: Zhao, Rongrong. China Agricultural University; ChinaFil: Conley, Christopher J.. University of California; Estados UnidosFil: Distelfeld, Assaf. Faculty Of Life Sciences, Department Of Molecular Biolo;Fil: Dubcovsky, Jorge. University of California; Estados Unidos. Howard Hughes Medical Institute ; Estados Unidos. Gordon & Betty Moore Foundation Investigator; Estados Unido

Reassessment of the evolution of wheat chromosomes 4A, 5A, and 7B.

Key messageComparison of genome sequences of wild emmer wheat and Aegilops tauschii suggests a novel scenario of the evolution of rearranged wheat chromosomes 4A, 5A, and 7B. Past research suggested that wheat chromosome 4A was subjected to a reciprocal translocation T(4AL;5AL)1 that occurred in the diploid progenitor of the wheat A subgenome and to three major rearrangements that occurred in polyploid wheat: pericentric inversion Inv(4AS;4AL)1, paracentric inversion Inv(4AL;4AL)1, and reciprocal translocation T(4AL;7BS)1. Gene collinearity along the pseudomolecules of tetraploid wild emmer wheat (Triticum turgidum ssp. dicoccoides, subgenomes AABB) and diploid Aegilops tauschii (genomes DD) was employed to confirm these rearrangements and to analyze the breakpoints. The exchange of distal regions of chromosome arms 4AS and 4AL due to pericentric inversion Inv(4AS;4AL)1 was detected, and breakpoints were validated with an optical Bionano genome map. Both breakpoints contained satellite DNA. The breakpoints of reciprocal translocation T(4AL;7BS)1 were also found. However, the breakpoints that generated paracentric inversion Inv(4AL;4AL)1 appeared to be collocated with the 4AL breakpoints that had produced Inv(4AS;4AL)1 and T(4AL;7BS)1. Inv(4AS;4AL)1, Inv(4AL;4AL)1, and T(4AL;7BS)1 either originated sequentially, and Inv(4AL;4AL)1 was produced by recurrent chromosome breaks at the same breakpoints that generated Inv(4AS;4AL)1 and T(4AL;7BS)1, or Inv(4AS;4AL)1, Inv(4AL;4AL)1, and T(4AL;7BS)1 originated simultaneously. We prefer the latter hypothesis since it makes fewer assumptions about the sequence of events that produced these chromosome rearrangements

A Space of Their Own: Arab Women Artists in Israel: Identity of a ‘Double-Minority’

This research paper focuses on the art of three women artists—Fatima Abu-Roomi, Samah Shihadi and Fatma Shanan. The research paper focuses on the work of three women artists who are ‘double-minority’—Fatima Abu-Roomi, Samah Shihadi, and Fatma Shanan. Their ‘double-minority’ status comes from being Arab women, raised in patriarchal communities as Muslims (Abu-Roomi and Shihadi), or Druze (Shanan), who live and work among a Jewish majority in the Western-based environment of Israel. The objectives of this research are to point out the significance of their art as an innovative and unique voice within the Israeli art scene that reflect the conditions of young Arab women living in Israel today. Through analysis of their art, the research will aim to explore the artistic strategies, topics, and styles, as a means of negotiating their identity as a ‘double-minority’. A feminist reading of the artwork will be followed by another theoretical point of view from the psychoanalyst Donald W. Winnicott who coined the term “potential space”. In different “potential spaces”, the artists question cultural boundaries, national issues of colonialism, and gender roles. Choosing art as an ideological site, as well as a practical platform, allows them to widely investigate their identity in a complex minority situation and formulate a path for social change

Quantitative trait loci conferring grain mineral nutrient concentrations in durum wheat 3 wild emmer wheat RIL population

Mineral nutrient malnutrition, and particularly deficiency in zinc and iron, afflicts over 3 billion people worldwide. Wild emmer wheat, Triticum turgidum ssp. dicoccoides, genepool harbors a rich allelic repertoire for mineral nutrients in the grain. The genetic and physiological basis of grain protein, micronutrients (zinc, iron, copper and manganese) and macronutrients (calcium, magnesium, potassium, phosphorus and sulfur) concentration was studied in tetraploid wheat population of 152 recombinant inbred lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (accession G18-16). Wide genetic variation was found among the RILs for all grain minerals, with considerable transgressive effect. A total of 82 QTLs were mapped for 10 minerals with LOD score range of 3.2–16.7. Most QTLs were in favor of the wild allele (50 QTLs). Fourteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. Significant positive correlation was found between grain protein concentration (GPC), Zn, Fe and Cu, which was supported by significant overlap between the respective QTLs, suggesting common physiological and/or genetic factors controlling the concentrations of these mineral nutrients. Few genomic regions (chromosomes 2A, 5A, 6B and 7A) were found to harbor clusters of QTLs for GPC and other nutrients. These identified QTLs may facilitate the use of wild alleles for improving grain nutritional quality of elite wheat cultivars, especially in terms of protein, Zn and Fe

Developmental patterns of a large set of barley (Hordeum vulgare) cultivars in response to ambient temperature

Ambient temperature plays an important role in plant development. In cereals, little is known about the exact effects of ambient temperature in the range between it being a vernalising agent and an abiotic stress factor; thus the genetic determinants involved in the registering and response to ambient temperature, and their natural variation has not been dissected either. Principally, we wished to establish the level of natural variation in response to ambient temperature in barley via studying plant phenological development. The responses to temperature of 168 barley genotypes of different provenances and seasonal growth habit groups were observed in controlled environments. The effects of four temperature regimes (13◦C, 16.5◦C, 18◦C and 23◦C) on the duration of plant phenophases were examined. The plant development was characterised in a series of consecutive phenophases that span the plant life cycle from germination through flowering to attainment of maximum plant height. Ambient temperature affected significantly plant development, with substantial variation in responses among the genotypes. Six major types of responses were identified, which depended strongly on seasonal growth habit, with only a small degree of overlap. Although the differences in the timing of development among clusters were significant under each temperature regime, the 23◦C treatment resulted in the largest diversity of responses, with significant changes in the ranking of the six clusters compared to other treatments. Two clusters showed particularly unusual responses to 23C: the development of one winter barley cluster was extremely accelerated by the 23C treatment, whereas the development of one spring barley cluster was significantly delayed. Ambient temperature assumes importance as a regulatory cue in the intricate and complex temporal and spatial regulation network of plant development in cereals and acts mostly through its regulatory effect on certain developmental phases such as the onset and duration of the intensive stem elongation

Phenotyping of field-grown wheat in the UK highlights contribution of light response of photosynthesis and flag leaf longevity to grain yield

Improving photosynthesis is a major target for increasing crop yields and ensuring food security. Phenotyping of photosynthesis in the field is critical to understand the limits to crop performance in agricultural settings. Yet, detailed phenotyping of photosynthetic traits is relatively scarce in field-grown wheat, with previous studies focusing on narrow germplasm selections. Flag leaf photosynthetic traits, crop development, and yield traits were compared in 64 field-grown wheat cultivars in the UK. Pre-anthesis and post-anthesis photosynthetic traits correlated significantly and positively with grain yield and harvest index (HI). These traits included net CO2 assimilation measured at ambient CO2 concentrations and a range of photosynthetic photon flux densities, and traits associated with the light response of photosynthesis. In most cultivars, photosynthesis decreased post-anthesis compared with pre-anthesis, and this was associated with decreased Rubisco activity and abundance. Heritability of photosynthetic traits suggests that phenotypic variation can be used to inform breeding programmes. Specific cultivars were identified with traits relevant to breeding for increased crop yields in the UK: pre-anthesis photosynthesis, post-anthesis photosynthesis, light response of photosynthesis, and Rubisco amounts. The results indicate that flag leaf longevity and operating photosynthetic activity in the canopy can be further exploited to maximize grain filling in UK bread wheat

The contribution of wheat to human diet and health

Wheat is the most important staple crop in temperate zones and is in increasing demand in countries undergoing urbanization and industrialization. In addition to being a major source of starch and energy, wheat also provides substantial amounts of a number of components which are essential or beneficial for health, notably protein, vitamins (notably B vitamins), dietary fiber, and phytochemicals. Of these, wheat is a particularly important source of dietary fiber, with bread alone providing 20% of the daily intake in the UK, and well-established relationships between the consumption of cereal dietary fiber and reduced risk of cardio-vascular disease, type 2 diabetes, and forms of cancer (notably colo-rectal cancer). Wheat shows high variability in the contents and compositions of beneficial components, with some (including dietary fiber) showing high heritability. Hence, plant breeders should be able to select for enhanced health benefits in addition to increased crop yield

“I am not an artist, I make art”: amateurish artists in Israel and the sense of creativity

This study deals with self-taught visual artists who are considered “amateurish” by the establishment of the Memorial Center in Kiryat Tiv’on, Israel, where they have exhibit their artwork. We will try to figure out both the explicit and implicit characteristics of “amateurish” artists, and challenge the supposed linkage between amateurism and lack of creativity. The methodology applied combines a sociological point of view, drawing on in-depth interviews with the artists, along with a visual analysis of the artwork produced. The theory of “modest” artists, by Marie Buscatto, and the theory of serious leisure perspective by Robert A. Stebbins, will contribute supportive classifications and categories for the analysis. We claim that the artists of our study are located on an axis between “amateurish” and “professional” within a fluid area of “serious leisure”. They are regarded as “amateurish” due to their lack of academic background in the arts, their relatively old age, having encountered lack of official recognition, having come across various obstacles in displaying their art and having received low remunerations. Aside from their marginal position in the art field, we were able to detect a few characteristics that distinguish their artwork from that of “professionals”. Our findings prove them to constitute an in-between category of “modest” or “serious-leisure-amateurish” artists, which blurs the dichotomy between “amateurish” and “professional” artists imposed by the establishment. We found these “modest” artists’ experiences to be creative, as well as some of their artwork; nevertheless, this kind of creativity seems to be disregarded by the establishment which perceives creativity as innovation. Santrauka Šis tyrimas susijęs su savamoksliais vizualiųjų menų kūrėjais, kurie vertinami kaip „mėgėjai“, Kirijat Tivone (Izraelis) įkūrus memorialinį centrą, kuriame jie eksponuoja savuosius meno kūrinius. Pabandysime išsiaiškinti tiek tikslias, tiek tik numanomas menininkų „mėgėjų“ charakteristikas bei užginčyti spėjamą mėgėjiškumo ir kūrybiškumo stokos sąsają. Taikoma metodologija apima sociologinį požiūrio tašką, remiantis išsamiais interviu su menininkais, taip pat meno kūrinio vizualinę analizę. „Kuklių“ menininkų teorija, kurią išplėtojo Marie Buscatto, ir rimtojo laisvalaikio perspektyva, kurią suformulavo Robertas A. Stebbinsas, padės analizei ją paremiančiomis klasifikacijomis ir kategorijomis. Tvirtiname, kad mūsų tiriamų menininkų vieta yra ties „mėgėjiškumo“ ir „profesionalumo“ ašimi, takioje „rimtojo laisvalaikio“ zonoje. Jie laikomi „mėgėjais“ dėl akademinio išsilavinimo menų srityje stokos, santykinai vyresnio amžiaus, oficialaus pripažinimo nebuvimo, iškilusių įvairių kliūčių demonstruoti savuosius meno kūrinius ir už juos gaunamą nedidelį finansinį atlygį. Nepaisant jų užimamos periferinės pozicijos meno srityje, vis dėlto galėjome nustatyti keletą charakteristikų, kurios atskiria jų meno kūrinius nuo tų, kuriuos sukūrė „profesionalai“. Mūsų išvados įrodo, kad jie priklauso tarpinei „kuklių“ ar „rimtojo laisvalaikio mėgėjų“ menininkų kategorijai, kuri panaikina įsitvirtinusią menininkų „mėgėjų“ ir „profesionalų“ dichotomiją. Nustatėme, kad šių „kuklių“ menininkų patirtis yra kūrybinio pobūdžio kaip ir kai kurie jų meno kūriniai; vis dėlto šio pobūdžio kūrybiškumas, regis, yra ignoruojamas tų sričių profesionalų, kurie suvokia kūrybiškumą kaip inovaciją. Reikšminiai žodžiai: mėgėjiškasis menas, menininkas mėgėjas, meno sritis, kūrybiškumas, profesionalus menininkas, vizualusis menas

Plasticity of Root System Architecture and Whole Transcriptome Responses Underlying Nitrogen Deficiency Tolerance Conferred by a Wild Emmer Wheat QTL.

Our aim was to elucidate mechanisms underlying nitrogen (N)-deficiency tolerance in bread wheat (cultivar Ruta), conferred by a wild emmer wheat QTL (WEW; IL99). We hypothesised that the tolerance in IL99 is driven by enhanced N-uptake through modification of root system architecture (RSA) underscored by transcriptome modifications. Severe N-deficiency (0.1 N for 26 days) triggered significantly higher plasticity in IL99 compared to Ruta by modifying 16 RSA traits; nine of which were IL99-specific. The change in root growth in IL99 was collectively characterised by a transition in root orientation from shallow to steep, increased root number and length, and denser networks, enabling nutrient acquisition from a larger volume and deeper soil layers. Gene ontology and KEGG-enrichment analyses highlighted IL99-specific pathways and candidate genes elevated under N-deficiency. This included Jasmonic acid metabolism, a key hormone mediating RSA plasticity (AOS1, TIFY, MTB2, MYC2), and lignification-mediated root strengthening (CYP73A, 4CL). N-metabolism was identified as a main shared pathway to IL99 and Ruta, with enhanced nitrate uptake predominant in IL99 (NRT2.4), while remobilisation was the main strategy in Ruta (NRT2.3). These findings provide novel insights into wheat plasticity response underlying tolerance to N-deficiency and demonstrate the potential of WEW for improving N-uptake under suboptimal conditions