Analysis on driving factors of microbial community succession in Jiuyao of Shaoxing Huangjiu (Chinese yellow rice wine)

The microbial ecosystem of fermented food is greatly disturbed by human activities.Jiuyao is important saccharification starter for brewing huangjiu. The interaction between environmental factors and microorganisms significantly affected the microbial community structure at different stages of Jiuyao manufacturing. This study combined environmental factor analysis and high-throughput sequencing technology to comprehensively analyze the specific changes of microbial community and environmental factors in each fermentation stage of Jiuyao production and their correlation. The results showed that the activities of liquefaction enzyme, glycosylation enzyme and acid protease reached the highest value on the 8 th day (192 h) after the beginning of fermentation, and the cellulase activity reached the highest value at the end of fermentation. Pediococcus（37.5 %-58.2 %）, Weissella（9.2 %-27.0 %） and Pelomonas（0.1 %-12.1 %） were the main microbial genera in the genus bacteria, and Saccharomycopsis（37.1 %-52.0 %）, Rhizopus（12.5 %-31.0 %） and Saccharomyces（4.0 %-20.5 %） were the main microbial genera in the genus fungi. The results of correlation analysis showed that the microbial communities in Jiuyao were closely related to environmental factors. Most microbial communities were positively correlated with temperature, but negatively correlated with ambient humidity, CO2 concentration, acidity and water content of Jiuyao. In addition, the transcription levels of enzymes related to microbial glucose metabolism in Jiuyao were higher in the late stage of Jiuyao fermentation. Interestingly, these enzymes had high transcription levels in fungi such as Saccharomycopsis, Rhizopus and Saccharomyces, as well as in bacteria such as Pediococcus and Lactobacillus. This study provides a reference for revealing the succession rule of microbial community structure caused by environmental factors during the preparation of Jiuyao in Shaoxing Huangjiu.

5-Aminolevulinic Acid and 24-Epibrassinolide Improve the Drought Stress Resilience and Productivity of Banana Plants

Plant growth, development, and productivity are adversely affected under drought conditions. Previous findings indicated that 5-aminolevulinic acid (ALA) and 24-epibrassinolide (EBL) play an important role in the plant response to adverse environmental conditions. This study demonstrated the role of ALA and EBL on oxidative stress and photosynthetic capacity of drought-stressed 'Williams' banana grown under the Egyptian semi-arid conditions. Exogenous application of either ALA or EBL at concentrations of 15, 30, and 45 mg·L-1 significantly restored plant photosynthetic activity and increased productivity under reduced irrigation; this was equivalent to 75% of the plant's total water requirements. Both compounds significantly reduced drought-induced oxidative damages by increasing antioxidant enzyme activities (superoxide dismutase 'SOD', catalase 'CAT', and peroxidase 'POD') and preserving chloroplast structure. Lipid peroxidation, electrolyte loss and free non-radical H2O2 formation in the chloroplast were noticeably reduced compared to the control, but chlorophyll content and photosynthetic oxygen evolution were increased. Nutrient uptake, auxin and cytokinin levels were also improved with the reduced abscisic acid levels. The results indicated that ALA and EBL could reduce the accumulation of reactive oxygen species and maintain the stability of the chloroplast membrane structure under drought stress. This study suggests that the use of ALA or EBL at 30 mg·L-1 can promote the growth, productivity and fruit quality of drought-stressed banana plants.

Correlations between allocation to foliar phosphorus fractions and maintenance of photosynthetic integrity in six mangrove populations as affected by chilling

Chilling restrains the distribution of mangroves. We tested whether foliar phosphorus (P) fractions and gene expression are associated with cold tolerance in mangrove species. We exposed seedlings of six mangrove populations from different latitudes to favorable, chilling and recovery treatments, and measured their foliar P concentrations and fractions, photochemistry, nighttime respiration, and gene expression. A Kandelia obovata (KO; 26.45°N) population completely and a Bruguiera gymnorhiza (Guangxi) (BGG; 21.50°N) population partially (30%) survived chilling. Avicennia marina (24.29°N), and other B. gymnorhiza (26.66°N, 24.40°N, and 19.62°N) populations died after chilling. Photosystems of KO and photosystem I of BGG were least injured. During chilling, leaf P fractions, except nucleic acid P in three populations, declined and photoinhibition and nighttime respiration increased in all populations, with the greatest impact in B. gymnorhiza. Leaf nucleic acid P was positively correlated with photochemical efficiency during recovery and nighttime respiration across populations for each treatment. Relatively high concentrations of nucleic acid P and metabolite P were associated with stronger chilling tolerance in KO. Bruguiera gymnorhiza exhibited relatively low concentrations of organic P in favorable and chilling conditions, but its partially survived population showed stronger compensation in nucleic acid P and Pi concentrations and gene expression during recovery.

The sensory and flavor characteristics of Shaoxing Huangjiu (Chinese rice wine) were significantly influenced by micro-oxygen and electric field

In order to improve the high cost of equipment and difficult management caused by the natural aging of Chinese rice wine (Huangjiu), micro-oxygen (MO) and electric field (PEF) technology are used to accelerate the aging of Huangjiu. The results showed that micro-oxygen and electric field have a significant effect on the sensory characteristics and flavor characteristics of Huangjiu. Compared with the naturally aged Huangjiu, the flavor compounds of Huangjiu treated with micro-oxygen and electric field increase significantly. Based on principal component analysis, Huangjiu processed at 0.35 mg L/day or 0.5 mg L/day combined electric field exhibited similar flavor to the natural aged Huangjiu, which was highly associated with long-chain fatty acid ethyl esters (C13-C18). Moreover, partial least squares regression demonstrated that sensory attributes of cereal aroma and astringency were highlighted after aging time, while fruit aroma, continuation, and full body were dominant after micro-oxygen and electric field treatment. Micro-oxygen and electric field effectively enhanced the quality of Huangjiu, which could be applied in other alcoholic beverages.

Humic Acid and Boron to Minimize the Incidence of Alternate Bearing and Improve the Productivity and Fruit Quality of Mango Trees

Mango production faces several challenges, such as nutrient deficiency, physiological stress, and alternate bearing, which eventually affect tree productivity. This study was carried out during the 2017 and 2018 seasons to evaluate the effect of single and combined applications of humic acid (as potassium humate; 0.15%, 0.30%, 0.45%) and boron (as boric acid; 300, 600 mg·L−1) on ‘Zebda’ mango trees grown at Dir AlMalak region, Sharkeya Governorate, Egypt. Foliar spray was applied twice before flowering (first week of January and first week of February), and a third spray was applied by the beginning of flowering (first week of March) in both seasons. Humic acid and boron effectively enhanced tree growth, flowering, yield, and fruit quality. Humic acid was more effective than boron in this respect. Combined application of both materials surpassed the single application of each material on overall tree physiology and annual productivity. The observed results may be a consequence of the increase in tree photosynthetic pigments, nutrients, organic solutes, and phytohormones such as auxins, gibberellins, and cytokinins. The reduction in abscisic acid content may be related to the role of humic acid and boron protecting the plant against destructive oxidative reactions; improving the ability of the trees to withstand environmental stresses; thereby reduce floral malformation percentage, minimize the incidence of alternate bearing, and improve annual tree productivity and fruit quality. The most pronounced effect in this regard was noted with the application of 0.30% humic acid + 600 mg·L−1 boric acid.

Foliar application of nanoparticles mitigates the chilling effect on photosynthesis and photoprotection in sugarcane

Chilling is one of the main abiotic stresses that adversely affect the productivity of sugarcane, in marginal tropical regions where chilling incidence occurs with seasonal changes. However, nanoparticles (NPs) have been tested as a mitigation strategy against diverse abiotic stresses. In this study, NPs such as silicon dioxide (nSiO₂; 5-15 nm), zinc oxide (nZnO; <100 nm), selenium (nSe; 100 mesh), graphene (graphene nanoribbons [GNRs] alkyl functionalized; 2-15 μm × 40-250 nm) were applied as foliar sprays on sugarcane leaves to understand the amelioration effect of NPs against negative impact of chilling stress on photosynthesis and photoprotection. To this end, seedlings of moderately chilling tolerant sugarcane variety Guitang 49 was used for current study and spilt plot was used as statistical design. The changes in the level chilling tolerance after the application of NPs on Guitang 49 were compared with tolerance level of chilling tolerant variety Guitang 28. NPs treatments reduced the adverse effects of chilling by maintaining the maximum photochemical efficiency of PSII (F_v/F_m), maximum photo-oxidizable PSI (P_m), and photosynthetic gas exchange. Furthermore, application of NPs increased the content of light harvesting pigments (chlorophylls and cartinoids) in NPs treated seedlings. Higher carotenoid accumulation in leaves of NPs treated seedlings enhanced the nonphotochemical quenching (NPQ) of PSII. Among the NPs, nSiO₂ showed higher amelioration effects and it can be used alone or in combination with other NPs to mitigate chilling stress in sugarcane.

Frequently asked questions about in vivo chlorophyll fluorescence: practical issues

The aim of this educational review is to provide practical information on the hardware, methodology, and the hands on application of chlorophyll (Chl) a fluorescence technology. We present the paper in a question and answer format like frequently asked questions. Although nearly all information on the application of Chl a fluorescence can be found in the literature, it is not always easily accessible. This paper is primarily aimed at scientists who have some experience with the application of Chl a fluorescence but are still in the process of discovering what it all means and how it can be used. Topics discussed are (among other things) the kind of information that can be obtained using different fluorescence techniques, the interpretation of Chl a fluorescence signals, specific applications of these techniques, and practical advice on different subjects, such as on the length of dark adaptation before measurement of the Chl a fluorescence transient. The paper also provides the physiological background for some of the applied procedures. It also serves as a source of reference for experienced scientists.

Identification and differential expression of two dehydrin cDNAs during maturation of Jatropha curcas seeds

Plant dehydrin proteins (DHNs) are known to be important for environmental stress tolerance and are involved in various developmental processes. Two full-length cDNAs JcDHN-1 and JcDHN-2 encoding two dehydrins from Jatropha curcas seeds were identified and characterized. JcDHN-1 is 764 bp long and contains an open reading frame of 528 bp. The deduced JcDHN-1 protein has 175 a.a. residues that form a 19.3-kDa polypeptide with a predicted isoelectric point (pI) of 6.41. JcDHN-2 is 855 bp long and contains an open reading frame of 441 bp. The deduced JcDHN-2 protein has 156 a.a. residues that form a 17.1-kDa polypeptide with a predicted pI of 7.09. JcDHN-1 is classified as type Y₃SK₂ and JcDHN-2 is classified as type Y₂SK₂ according to the YSK shorthand for structural classification of dehydrins. Homology analysis indicates that both JcDHN-1 and JcDHN-2 share identity with DHNs of other plants. Analysis of the conserved domain revealed that JcDHN-2 has glycoside hydrolase GH20 super-family activity. Quantitative real time PCR analysis for JcDHN-1 and JcDHN-2 expression during seed development showed increasing gene expression of both their transcript levels along with the natural dehydration process during seed development. A sharp increase in JcDHN-2 transcript level occurred in response to water content dropping from 42% in mature seeds to 12% in dry seeds. These results indicate that both JcDHNs have the potential to play a role in cell protection during dehydration occurring naturally during jatropha orthodox seed development.

Identification and expression analysis of two small heat shock protein cDNAs from developing seeds of biodiesel feedstock plant Jatropha curcas

Plant small heat shock proteins (sHSPs) are known to be important for environmental stress tolerance and involved in various developmental processes. In this study, two full-length cDNAs encoding sHSPs, designated JcHSP-1 and JcHSP-2, were identified and characterized from developing seeds of a promising biodiesel feedstock plant Jatropha curcas by expressed sequence tag (EST) sequencing of embryo cDNA libraries and rapid amplification of cDNA ends (RACE). JcHSP-1 and JcHSP-2 contained open-reading frames encoding sHSPs of 219 and 157 amino acids, with predicted molecular weights of 24.42kDa and 18.02kDa, respectively. Sequence alignment indicated that both JcHSP-1 and JcHSP-2 shared high similarity with other plant sHSPs. Real-time quantitative RT-PCR analysis showed that the transcriptional level of both JcHSP-1 and JcHSP-2 increased along with natural dehydration process during seed development. A sharp increase of JcHSP-2 transcripts occurred in response to water content dropping from 42% in mature seeds to 12% in dry seeds. Western blot analysis revealed that the accumulation profile of two cross-reacting proteins, whose molecular weight corresponding to the calculated size of JcHSP-1 and JcHSP-2, respectively, was well consistent with the mRNA expression pattern of JcHSP-1 and JcHSP-2 in jatropha seeds during maturation and natural dehydration. These results indicated that both JcHSPs might play an important role in cell protection and seed development during maturation of J. curcas seeds.