Production and Properties of Microbial Polyhydroxyalkanoates Synthesized from Hydrolysates of Jerusalem Artichoke Tubers and Vegetative Biomass

One of the major challenges in PHA biotechnology is optimization of biotechnological processes of the entire synthesis, mainly by using new inexpensive carbon substrates. A promising substrate for PHA synthesis may be the sugars extracted from the Jerusalem artichoke. In the present study, hydrolysates of Jerusalem artichoke (JA) tubers and vegetative biomass were produced and used as carbon substrate for PHA synthesis. The hydrolysis procedure (the combination of aqueous extraction and acid hydrolysis, process temperature and duration) influenced the content of reducing substances (RS), monosaccharide contents, and the fructose/glucose ratio. All types of hydrolysates tested as substrates for cultivation of three strains—C. necator B-10646 and R. eutropha B 5786 and B 8562—were suitable for PHA synthesis, producing different biomass concentrations and polymer contents. The most productive process, conducted in 12-L fermenters, was achieved on hydrolysates of JA tubers (X = 66.9 g/L, 82% PHA) and vegetative biomass (55.1 g/L and 62% PHA) produced by aqueous extraction of sugars at 80 °C followed by acid hydrolysis at 60 °C, using the most productive strain, C. necator B-10646. The effects of JA hydrolysates on physicochemical properties of PHAs were studied for the first time. P(3HB) specimens synthesized from the JA hydrolysates, regardless of the source (tubers or vegetative biomass), hydrolysis conditions, and PHA producing strain employed, exhibited the 100–120 °C difference between the Tmelt and Tdegr, prevailing of the crystalline phase over the amorphous one (Cx between 69 and 75%), and variations in weight average molecular weight (409–480) kDa. Supplementation of the culture medium of C. necator B-10646 grown on JA hydrolysates with potassium valerate and ε-caprolactone resulted in the synthesis of P(3HB-co-3HV) and P(3HB-co-4HB) copolymers that had decreased degrees of crystallinity and molecular weights, which influenced the porosity and surface roughness of polymer films prepared from them. The study shows that JA hydrolysates used as carbon source enabled productive synthesis of PHAs, comparable to synthesis from pure sugars. The next step is to scale up PHA synthesis from JA hydrolysates and conduct the feasibility study. The present study contributes to the solution of the critical problem of PHA biotechnology—finding widely available and inexpensive substrates.

Impacts of Carbon Dioxide Enrichment on Landrace and Released Ethiopian Barley (Hordeum vulgare L.) Cultivars

Barley (Hordeum vulgare L.) is an important food security crop due to its high-stress tolerance. This study explored the effects of CO2 enrichment (eCO2) on the growth, yield, and water-use efficiency of Ethiopian barley cultivars (15 landraces, 15 released). Cultivars were grown under two levels of CO2 concentration (400 and 550 ppm) in climate chambers, and each level was replicated three times. A significant positive effect of eCO2 enrichment was observed on plant height by 9.5 and 6.7%, vegetative biomass by 7.6 and 9.4%, and grain yield by 34.1 and 40.6% in landraces and released cultivars, respectively. The observed increment of grain yield mainly resulted from the significant positive effect of eCO2 on grain number per plant. The water-use efficiency of vegetative biomass and grain yield significantly increased by 7.9 and 33.3% in landraces, with 9.5 and 42.9% improvement in released cultivars, respectively. Pearson’s correlation analysis revealed positive relationships between grain yield and grain number (r = 0.95), harvest index (r = 0.86), and ear biomass (r = 0.85). The response of barley to eCO2 was cultivar dependent, i.e., the highest grain yield response to eCO2 was observed for Lan_15 (122.3%) and Rel_10 (140.2%). However, Lan_13, Land_14, and Rel_3 showed reduced grain yield by 16, 25, and 42%, respectively, in response to eCO2 enrichment. While the released cultivars benefited more from higher levels of CO2 in relative terms, some landraces displayed better actual values. Under future climate conditions, i.e., future CO2 concentrations, grain yield production could benefit from the promotion of landrace and released cultivars with higher grain numbers and higher levels of water-use efficiency of the grain. The superior cultivars that were identified in the present study represent valuable genetic resources for future barley breeding.

Ecophysiological genomics identifies a pleiotropic locus mediating drought tolerance in sorghum

ABSTRACTDrought is a key constraint on plant productivity and threat to food security. Sorghum (Sorghum bicolor L. Moench), a global staple food and forage crop, is among the most drought-adapted cereal crops, but its adaptation is not yet well understood. This study aims to better understand the genetic basis of preflowering drought in sorghum and identify loci underlying variation in water use and yield components under drought. A panel of 219 diverse sorghum from West Africa was phenotyped for yield components and water use in an outdoor large-tube lysimeter system under well-watered (WW) versus a preflowering drought water-stressed (WS) treatment. The experimental system was validated based on characteristic drought response in international drought tolerance check genotypes and genome-wide association studies (GWAS) that mapped the major height locus at QHT7.1 and Dw3. GWAS further identified marker trait associations (MTAs) for drought-related traits (plant height, flowering time, forage biomass, grain weight, water use) that each explained 7–70% of phenotypic variance. Most MTAs for drought-related traits correspond to loci not previously reported, but some MTA for forage biomass and grain weight under WS co-localized with staygreen post-flowering drought tolerance loci (Stg3a and Stg4). A globally common allele at S7_50055849 is associated with several yield components under drought, suggesting that it tags a major pleiotropic variant controlling assimilate partitioning to grain versus vegetative biomass. The GWAS findings revealed oligogenic variants for drought tolerance in sorghum landraces which could be used as trait predictive markers for improved drought adaptation.

Performance of Different-Use Type Industrial Hemp Cultivars under Mid-Atlantic Region Conditions

Due to recent classification as a commodity crop in North America, producer interest in industrial hemp (Cannabis sativa L.) has increased. In the Commonwealth of Virginia, there is a need to evaluate foreign-developed industrial hemp for its adaptability and to develop new cultivars suited to local climatic conditions. Eight cultivars (‘Bialobrzeskie’, ‘Canda’, ‘Fedora 17’, ‘Felina 32’, ‘Joey’, ‘Tygra’, ‘USO 31’, and ‘Wojko’) were evaluated for grain and five (‘Bialobrzeskie’, ‘Carmagnola’, ‘Fedora 17’, ‘Futura 75’, and ‘Wojko’) for vegetative biomass. An experiment carried out at the Virginia State Research and Demonstration (Randolph) farm was laid out in a randomized complete block design with three replications. The results show that cultivars differed in the cumulative growing degree days (CGDD) needed for growth phase transitions, with ‘USO 31’ having an early transition to the reproductive phase. In addition, ‘Fedora 17’ produced greater grain yield and may have the potential for greater performance with better management to improve its adaptability to local conditions. Across cultivars and years, the grain protein content averaged 241 g kg−1 and the mineral elements were at sufficient levels for animal and human nutrition. ‘Carmagnola’ produced greater biomass yield and has the potential for adoption as local fiber cultivar.

Characterization and potential utilization of recently available milk thistle, Silybum marianum (L.) Gaertn., wild type and mutant accessions

Milk thistle, Silybum marianum (L.) Gaertn. (Asteraceae), is an economically important medicinal plant utilized for silymarin production. Moreover, the species has been positively evaluated for vegetable oil and biomass production. Despite these positive characteristics, milk thistle is still marked by traits that are typical of undomesticated species (most importantly natural fruit dispersal at maturity) and requires further genetic improvement for its complete exploitation. This manuscript summarizes all the information collected through time about a collection of nine milk thistle wild and mutant lines and it discusses the possible further utilization of these genotypes. The accessions are characterized by interesting traits related to: fruit silymarin composition (S. marianum chemotype A and B), fruit fatty acid composition (high oleic and high stearic acid lines), fruit condensed tannins content, vegetative biomass composition (modification of xylans or lignin content), vegetative biomass structure (dwarf and tall lines), modifications of leaf variegation (hypervareigated line) and different types of fruit shatter resistance at maturity. All the lines underwent subsequent generations of selfing and are stable for all the described traits. The accessions will be made available at the Genebank of the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK, Gatersleben) and may prove to be a useful genetic material for the improvement of qualitative fruit traits (silymarin quality, fatty acid composition) and for the further development of shatter-resistant S. marianum genotypes towards the complete domestication of this promising species.

Allometric Models for Aboveground Biomass of Six Common Subtropical Shrubs and Small Trees

Background: The aboveground biomass (AGB) of shrubs and small trees is the main component for the productivity and carbon storage of understory vegetation in subtropical natural secondary forests. However, few allometric models exist for shrubs and small trees, even though they can accurately evaluate understory vegetative biomass. Methods: To estimate the ABG of six common shrub and small tree species, we utilized harvesting to sample 206 individuals, and developed species-specific and multi-species allometric models based on four predictors including height (H), stem diameter (D), crown area (Ca), and wood density (ρ). Results: As expected, these six shrub and small tree species possessed greater biomass in their stems in contrast to branches, with the lowest biomass in the leaves. Species-specific allometric models that employed D and the combined variables of D2H and ρDH as predictors, could accurately estimate the components and total AGB, with R2 values ranging from between 0.602 and 0.971. A multi-species shrub allometric model revealed that ρDH was the best predictor, with R2 values ranging from between 0.809 and 0.890. Conclusions: These results indicated that H and D were effective predictors for the models to estimate the AGB of the six shrub and small tree species, and the introduction of ρ improved their accuracy. The optimal model selected in this study could be applied to estimate the biomass of shrubs and small trees in the subtropical regions.

NH787 EMS mutant of rice variety Nagina22 exhibits higher phosphate use efficiency

Rice (Oryza sativa L.), a major dietary source, is often cultivated in soils poor in available inorganic orthophosphate (Pi), which is a key nutrient for growth and development. Poor soils are amended by phosphorus (P) fertilizer, which is derived from the non-renewable rock phosphate reserves. Therefore, there is a need for developing rice varieties with high productivity under low P conditions. At the ICAR-IIRR, ethyl methanesulfonate (EMS) mutagenized rice genotype Nagina22 (N22) were screened for high grain yield in Pi-deprived soil, which led to the identification of ~ 10 gain-of-function mutants including NH787. Here, detailed comparative morphophysiological, biochemical, and molecular analyses of N22 and NH787 were carried out in hydroponics and potting soil under different Pi regimes. Under Pi-deprived condition, compared with N22, NH787 exhibited higher root and vegetative biomass, the number of tillers, and grain yield. The augmented agronomic traits of NH787 were corroborated with significantly higher photosynthetic rate, pollen fertility, stigma receptivity, and the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Further, several genes involved in the maintenance of Pi homeostasis (GPH) were differentially regulated. The study thus revealed a wide-spectrum influence of the mutation in NH787 that contributed towards its higher Pi use efficiency (PUE).

Gain-of-Function NH787 Ethylmethanesulfonate Mutant of Nagina22 Rice Variety Confers Augmented PUE

Rice (Oryza sativa L.), a major dietary source, is often cultivated in soils poor in available inorganic orthophosphate (Pi), which is a pivotal nutrient for growth and development. Poor soils are amended by phosphorus (P) fertilizer, which is derived from the non-renewable rock phosphate reserves. Therefore, there is a need for developing rice varieties with high productivity under low P conditions. At the ICAR-IIRR, ethyl methanesulfonate (EMS) mutagenized rice genotype Nagina22 (N22) were screened for high grain yield in Pi-deprived soil, which led to the identification of ~10 gain-of-function mutants including NH787. Here, detailed comparative morphophysiological, biochemical, and molecular analyses of N22 and NH787 were carried out in hydroponics and potting soil under different Pi regimes. Under Pi-deprived conditions, compared with N22, NH787 exhibited higher root and vegetative biomass, the number of tillers, and grain yield. The augmented agronomic traits of NH787 were corroborated with significantly higher photosynthetic rate, pollen fertility, stigma receptivity, and the activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). Further, several genes involved in the maintenance of Pi homeostasis (GPH) were differentially regulated. The study thus revealed a wide-spectrum influence of the mutation in NH787 that contributed towards its higher Pi use efficiency.

Plant morphology, vegetative biomass composition and energy content of three different Silybum marianum accessions

Silybum marianum (L.) Gaertn. (milk thistle) is plant species that has been utilized principally for medicinal purposes for more than 2000 years. Recently it was proposed for biomass production in marginal environments, but vegetative biomass compositional analyses had not been available so far. The study of plant morphology and biomass composition was conducted on three different S. marianum accessions grown under open field conditions. The results indicate that plant morphological traits show major differences between accessions: this suggests that the available natural variability can be further utilized in order to develop improved S. marianum cultivars. Biomass compositional analysis shows that extractives, ash, lignin and cellulose content are comparable to other herbaceous bioenergy crops and that these traits display only limited variability in the studied accessions. Hemicellulose fraction is composed only by xylans and its content appears averagely lower in comparison to other herbaceous biomasses. Interestingly, in S. marianum biomass total nitrogen content is lower if compared to other herbaceous species. The possible involvement of this specific biomass trait in S. marianum nitrogen utilization efficiency has to be further investigated.