Prediction of near-term climate change impacts on UK wheat quality and the potential for adaptation through plant breeding

Wheat is a major crop worldwide, mainly cultivated for human consumption and animal feed. Grain quality is paramount in determining its value and downstream use. While we know that climate change threatens global crop yields, a better understanding of impacts on wheat end-use quality is also critical. Combining quantitative genetics with climate model outputs, we investigated UK-wide trends in genotypic adaptation for wheat quality traits. In our approach, we augmented genomic prediction models with environmental characterisation of field trials to predict trait values and climate effects in historical field trial data between 2001 and 2020. Addition of environmental covariates, such as temperature and rainfall, successfully enabled prediction of genotype by environment interactions (G × E), and increased prediction accuracy of most traits for new genotypes in new year cross validation. We then extended predictions from these models to much larger numbers of simulated environments using climate scenarios projected under Representative Concentration Pathways 8.5 for 2050–2069. We found geographically varying climate change impacts on wheat quality due to contrasting associations between specific weather covariables and quality traits across the UK. Notably, negative impacts on quality traits were predicted in the East of the UK due to increased summer temperatures while the climate in the North and South-west may become more favourable with increased summer temperatures. Furthermore, by projecting 167,040 simulated future genotype–environment combinations, we found only limited potential for breeding to exploit predictable G × E to mitigate year-to-year environmental variability for most traits except Hagberg falling number. This suggests low adaptability of current UK wheat germplasm across future UK climates. More generally, approaches demonstrated here will be critical to enable adaptation of global crops to near-term climate change.     

Monogamy in black vultures: genetic evidence from DNA fingerprinting

Recent research has indicated that avian mating systems maycommonly deviate from monogamy due to extrapair fertilizations(EPFs). Because the majority of avian species have long beenconsidered monogamous, accurate measurement of the frequencyof EPFs in a variety of species is important to enhance understandingof the evolution of avian mating systems. We used DNA fingerprintingto investigate the apparently monogamous mating system of blackvultures (Coragyps airaius) by assaying parentage within severalnuclear families. Monogamy is suggested in black vultures becausemated pairs exhibit long-term pair bonding and year-round association,and share incubation and nestling feeding duties equally. Thirtytwobreeders and 36 nestlings representing 16 complete nuclear familieswere tagged for individual identification and sampled for DNAanalysis using 2 restriction enzymes and 3 probes for hypervariableregions. Putative parents were assigned parentage in all cases.We empirically examined the probability of detecting EPFs bycomparing nestlings' fingerprints to those of a putative parentand another randomly chosen adult. All putative parents couldbe assigned with 95%confidence and all outside adults couldbe similarly excluded. There is therefore no evidence for successfulEPFs in this population, indicating a mating system that doesnot deviate from strict monogamy. The complex social behaviorof black vultures may eliminate the opportunity for EPFs dueto the prohibition of copulations in the presence of relatives.     

Bioremediation of experimental petroleum spills on mineral soils in the Vestfold Hills,Antarctica

The effect of nutrient and water enhancement on the biodegradation of petroleum was tested in Antarctic mineral soils. Nitrogen, phosphorus and potassium were applied in solution, with or without gum xanthan or plastic covers, to sites artificially contaminated with distillate. The effectiveness of these procedures was assessed by measuring changes in total petroleum hydrocarbons; heptadecane/pristane and octadecane/phytane ratios; in concentrations of major hydrocarbon components and in microbial numbers and activity.Significantly lower hydrocarbon concentrations were recorded after one year in soils treated with fertilizer solutions, but only in the surface 3 cm. These soils also showed lowered heptadecane/pristane and octadecane/ phytane ratios and had the highest levels of microbial activity relative to other plots. Soils treated with gum xanthan. or covered with plastic had the highest residual hydrocarbon levels. Both treatments inhibited evaporative loss of hydrocarbon, and there were indications that gum xanthan was utilized by the microbiota as an alternative carbon source to distillate. Higher temperatures were recordecd under the plastic but no stimulation of biodegradation was detected.Estimated numbers of metabolically active bacteria were in the range 10⁷ to 10⁸ g^–1 dry weight of soil, with an estimated biomass of 0.03 to 0.26 mg g^–1 soil. Estimated numbers of amoebae were in the range 10⁶ to 10⁷ g^–1 soil (biomass of 2 to 4 mgg^–1). The highest populations were recorded in fertilized, contaminated soils, the only soils where petroleum degradation was demonstrated.     

Cavity-nesting birds are limited by nesting habitat in Neotropical agricultural landscapes

Most studies comparing biodiversity between natural and human-modified landscapes focus on patterns in species occurrence or abundance, but do not consider how different habitat types meet species' breeding requirements. Organisms that use or nest in tree cavities may be especially threatened by habitat conversion due to the loss of their nesting sites. Although cavity-nesting bird diversity is highest in the tropics, little is known about how tropical birds use cavities, how agriculture affects their reproductive biology, and how effective nest boxes could be as a conservation strategy in tropical agriculture. Here, we explored how habitat conversion from tropical forests to pasture affects the abundance, nesting habitat availability, and nest success of cavity-nesting birds in Northwest Ecuador. We conducted bird surveys and measured natural cavity availability and use in forest and agriculture. We also added artificial nest boxes to forest and agriculture to see whether cavity limitation in agriculture would elicit higher use of artificial nest boxes. We found evidence of cavity limitation in agriculture—there were many more natural cavities in forest than in agriculture, as well as more avian use of nest boxes placed in agriculture as compared to forest. Our results suggest that it is important to retain remnant trees in tropical agriculture to provide critical nesting habitat for birds. In addition, adding nest boxes to tropical agricultural systems could be a good conservation strategy for certain species, including insectivores that could provide pest-control services to farmers. Abstract in Spanish is available with online material.     

Linkage of the Murine Transforming Growth Factor α Gene with Igk, Ly-2, and Fabp1 on Chromosome 6

TGFα is a mitogenic polypeptide found in the conditioned media of transformed cell lines as well as in various solid tumors. Although its physiological role in normal tissues is uncertain, the autocrine action of TGFα on the EGF receptor is postulated to play a role in tumorigenesis. To explore the possibility that pre-existing mouse mutants might have concordance with the mouse TGFα locus (Tgfa) we sought to establish the chromosomal localization of the murine TGFα gene. Using Southern analysis we have detected NcoI and PvuII RFLP in the TGFα gene of progenitor RI mouse strains. These RFLPs have been used to analyze four different RI sets of DNA and to assign Tgfa to the 35-cM region of chromosome 6. Linkage has been established and the data suggest that the distance between Igk and wa-1 anchor loci may be less than 8 cM and that the gene order for the proximal to mid region of mouse chromosome 6 may be: Ggc-Xmmv27-[Brp-1, Lvp-1, Ms6-4]-[Igk, Ly2, Ly3 Odc-rs5, Rn7s-6, Fabp1]-[Tgfa/wa-1]-IL5-R. Homology of synteny has been further defined between the proximal region of mouse chromosome 6 and with the 2p 13-p11 region of human chromosome 2 encompassing TGFA, IGK, CD8A, and FABP1 .     

Mapping of the human homologs of the murine paired-box-containing genes

Mutations in paired-box-containing (Pax) genes have recently been found to be the primary lesions underlying human genetic disorders such as Waardenburg's Syndrome type 1 and mouse developmental mutants such as undulated (un), splotch (Sp), and small eye (Sey). In addition, PAX-6 is a strong candidate gene for aniridia in man. Eight independent Pax genes have been isolated in the mouse. All eight map to distinct regions of the mouse genome; they do not appear to be clustered in the same way as some groups of homeobox-containing genes. We have now mapped the human homologs of all eight of these genes; PAX genes are found on human Chromosomes (Chr) 1, 2, 7, 9, 10, 11, and 20.     

THE ECOLOGICAL IMPACT OF ALLELOPATHY IN AILANTHUS ALTISSIMA (SIMAROUBACEAE)

Compounds inhibitory to the growth of neighboring plant species were found in significant concentrations in the leaves and stems of young Ailanthus altissima ramets. The surrounding soil also contained appreciable concentrations of similarly acting toxins. Individuals of neighboring plant species have either incorporated active portions of inhibitory compounds or responded to Ailanthus by producing growth-inhibiting substances. Under greenhouse conditions, individuals of neighboring plant species previously unexposed to Ailanthus in the field were found to be more susceptible to the Ailanthus toxins than individuals previously exposed. Moreover, seeds produced by unexposed populations were also more susceptible to Ailanthus toxins than seeds produced by previously exposed populations. These differences demonstrated that the allelochemicals of Ailanthus altissima exhibited a measurable impact upon neighboring plant species. Since the progeny of these populations displayed a differential response to Ailanthus toxin, this phenotypic difference between the two populations may have a heritable basis.     

The elongation of amylose and amylopectin chains in isolated starch granules

The aim of this work was to investigate the conditions required for amylose synthesis in starch granules. Although the major granule-bound isoform of starch synthase - GBSSI - catalyses the synthesis of amylose in vivo, ¹⁴C from ADP[¹⁴C]glucose was incorporated primarily into a specific subset of amylopectin chains when supplied to starch granules isolated from pea (Pisum sativum L.) embryos and potato (Solanum tuberosum L.) tubers. Incubation of granules with soluble extracts of these organs revealed that the extracts contained compounds that increased the incorporation of ¹⁴C into amylose. These compounds were rendered inactive by treatment of the extracts with α-glucosidase, suggesting that they were malto-oligosaccharides. Consistent with this idea, provision of pure malto-oligosaccharides to isolated granules resulted in a dramatic shift in the pattern of incorporation of ¹⁴C, from amylopectin chains to amylose molecules. Comparison of the pattern of incorporation in granules from wild-type peas and lam mutant peas which lack GBSSI showed that this effect of malto-oligosaccharides was specifically on GBSSI. The significance of these results for understanding of the synthesis of amylose and amylopectin in storage organs is discussed.