Identification of Salt Tolerance-related microRNAs and Their Targets in Maize (Zea mays L.) Using High-throughput Sequencing and Degradome Analysis

To identify the known and novel microRNAs (miRNAs) and their targets that are involved in the response and adaptation of maize (Zea mays) to salt stress, miRNAs and their targets were identified by a combined analysis of the deep sequencing of small RNAs (sRNA) and degradome libraries. The identities were confirmed by a quantitative expression analysis with over 100 million raw reads of sRNA and degradome sequences. A total of 1040 previously known miRNAs were identified from four maize libraries, with 762 and 726 miRNAs derived from leaves and roots, respectively, and 448 miRNAs that were common between the leaves and roots. A total of 37 potential new miRNAs were selected based on the same criteria in response to salt stress. In addition to known miR167 and miR164 species, novel putative miR167 and miR164 species were also identified. Deep sequencing of miRNAs and the degradome [with quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses of their targets] showed that more than one species of novel miRNA may play key roles in the response to salinity in maize. Furthermore, the interaction between miRNAs and their targets may play various roles in different parts of maize in response to salinity

Molecular Mechanisms of Fiber Differential Development between G. barbadense and G. hirsutum Revealed by Genetical Genomics

Cotton fiber qualities including length, strength and fineness are known to be controlled by genes affecting cell elongation and secondary cell wall (SCW) biosynthesis, but the molecular mechanisms that govern development of fiber traits are largely unknown. Here, we evaluated an interspecific backcrossed population from G. barbadense cv. Hai7124 and G. hirsutum acc. TM-1 for fiber characteristics in four-year environments under field conditions, and detected 12 quantitative trait loci (QTL) and QTL-by-environment interactions by multi-QTL joint analysis. Further analysis of fiber growth and gene expression between TM-1 and Hai7124 showed greater differences at 10 and 25 days post-anthesis (DPA). In this two period important for fiber performances, we integrated genome-wide expression profiling with linkage analysis using the same genetic materials and identified in total 916 expression QTL (eQTL) significantly (P<0.05) affecting the expression of 394 differential genes. Many positional cis-/trans-acting eQTL and eQTL hotspots were detected across the genome. By comparative mapping of eQTL and fiber QTL, a dataset of candidate genes affecting fiber qualities was generated. Real-time quantitative RT-PCR (qRT-PCR) analysis confirmed the major differential genes regulating fiber cell elongation or SCW synthesis. These data collectively support molecular mechanism for G. hirsutum and G. barbadense through differential gene regulation causing difference of fiber qualities. The down-regulated expression of abscisic acid (ABA) and ethylene signaling pathway genes and high-level and long-term expression of positive regulators including auxin and cell wall enzyme genes for fiber cell elongation at the fiber developmental transition stage may account for superior fiber qualities

Leaf cuticular wax content is involved in cotton leaf curl virus disease resistance in cotton (Gossypium hirsutum L.)

Cotton leaf curl virus disease (CLCuVD) limits cotton production in many cotton growing countries of the world, including Pakistan. In the past, efforts were made to combat this disease by different approaches. Cuticular wax is reported to confer resistance to plants against various biotic and abiotic stresses. Present study was designed to assess the role of cuticular wax content (WC) to resist CLCuVD infestation. The WC of 42 cotton genotypes, originating from various countries (Pakistan, USA, China, etc.), was quantified during two culture periods (2015 & 2016). Cotton germplasm was also scored for % disease index (%DI), seed cotton yield (SCY), number of bolls/plant (NB), and plant height (PHt) for the same culture periods. Significant negative correlation between WC and %DI was found during the two years of experimentation. WC was found positively correlated with SCY and NB. Six cotton genotypes (A-7233, B-557, A-162, BLANCO-3363, CIM-473, and SLH-2010-11) did not show any signs of CLCuVD infestation during both 2015 and 2016. These cotton genotypes contained relatively higher WC. The results from analysis of variance (ANOVA) demonstrated that there were significant differences among genotypes for %DI, WC, SCY, NB, and PHt. These results indicated that WC was involved in resisting CLCuVD and it also had positive effect on plant growth and yield potential. On the basis of these findings, it was concluded that cuticular wax could be used as an indirect criterion for distinguishing and selecting resistant/susceptible cotton genotypes

EFFECT OF LIGNIN CONTENT ON ENZYMATIC HYDROLYSIS OF FURFURAL RESIDUES

The enzymatic saccharification of pretreated furfural residues with different lignin content was studied to verify the effect of lignin removal in the hydrolysis process. The results showed that the glucose yield was improved by increasing the lignin removal. A maximum glucose yield of 96.8% was obtained when the residue with a lignin removal of 51.4% was hydrolyzed for 108 h at an enzyme loading of 25 FPU/g cellulose. However, further lignin removal did not increase the hydrolysis. The effect of enzyme loading on the enzymatic hydrolysis was also explored in this work. It was concluded that a high glucose yield of 90% was achieved when the enzyme dosage was reduced from 25 to 15 FPU/g cellulose, which was cost-effective for the sugar and ethanol production. The structures of raw material and delignified samples were further characterized by XRD and scanning electron microscopy (SEM)

H2O2 Oxidation of Corncob Holocellulose as a Dry-strength Additive for Paper

Corncob, an underutilized agricultural byproduct, was used as the raw material to make a dry-strength additive for paper. Corncob was ground into 80, 100, 150, and 200 mesh powder. The powder was treated with sodium chlorite to remove lignin, and the resulting holocellulose was modified with hydrogen peroxide. The influences of oxidation time, concentration of hydrogen peroxide, dosage of paper strength agent, and the dosage of aluminum sulfate on the paper properties were studied. The results indicate that the oxidized corncobs holocellulose can improve the tensile index, burst index, and folding endurance of paper. Compared with control paper, when the concentration of hydrogen peroxide was 0.9%, the tensile index, burst index, and folding endurance were increased by 24.2%, 14.1%, and 463.8%, respectively. The particle size of raw material, dosage of strengthening agent or aluminum sulfate greatly influences paper properties. Scanning electron microscopy (SEM) analysis showed that the combination between the fibers was improved after adding the strengthening agent, thus improving the strength of the paper. The results can provide a new method for value-added use of corncob

Cationization of Corncob Holocellulose as a Paper Strengthening Agent

In this paper, milled corncob powder was treated with sodium chlorite to remove lignin, and the resulting holocellulose was optionally modified with cationic agent. The derivative product was investigated using elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). The influences of the dosage of the cationic agent, reaction temperature, particle size, dosage of paper strengthening agent, and pH value of the pulp on the paper physical properties were studied. The results indicated that cationic corncob holocellulose can improve the tensile index, burst index, and folding endurance of paper. When the dosage of cationic agent was 25% and the reaction temperature was set to 70 °C, the resulting tensile index, burst index, and folding endurance increased by 7.15%, 13.74%, and 55.95%, respectively, when compared with the control paper. The particle size of the raw material and the dosage of strengthening agent also greatly influenced the paper’s properties. The SEM analysis showed that the combination of fibers improved the strength properties of the paper after adding the strengthening agent. These results provide a method for value-added use of corncob waste

Leaf cuticular wax content is involved in cotton leaf curl virus disease resistance in cotton (Gossypium hirsutum L.)

Cotton leaf curl virus disease (CLCuVD) limits cotton production in many cotton growing countries of the world, including Pakistan. In the past, efforts were made to combat this disease by different approaches. Cuticular wax is reported to confer resistance to plants against various biotic and abiotic stresses. Present study was designed to assess the role of cuticular wax content (WC) to resist CLCuVD infestation. The WC of 42 cotton genotypes, originating from various countries (Pakistan, USA, China, etc.), was quantified during two culture periods (2015 & 2016). Cotton germplasm was also scored for % disease index (%DI), seed cotton yield (SCY), number of bolls/plant (NB), and plant height (PHt) for the same culture periods. Significant negative correlation between WC and %DI was found during the two years of experimentation. WC was found positively correlated with SCY and NB. Six cotton genotypes (A-7233, B-557, A-162, BLANCO-3363, CIM-473, and SLH-2010-11) did not show any signs of CLCuVD infestation during both 2015 and 2016. These cotton genotypes contained relatively higher WC. The results from analysis of variance (ANOVA) demonstrated that there were significant differences among genotypes for %DI, WC, SCY, NB, and PHt. These results indicated that WC was involved in resisting CLCuVD and it also had positive effect on plant growth and yield potential. On the basis of these findings, it was concluded that cuticular wax could be used as an indirect criterion for distinguishing and selecting resistant/susceptible cotton genotypes

Oxidized Konjac Glucomannan as a Paper Strength Agent

A paper strength agent is an important type of chemical additive used in the papermaking industry. In this work some new paper strengthening agent samples were obtained by treating konjac glucomannan with hydrogen peroxide under acidic conditions, and their effects on paper properties were studied. Results showed that oxidized konjac glucomannan (OKG) can improve the paper properties effectively. When 1% oxidized glucomannan (oxidation 60 min, 35 C) was added, the burst index, tensile index, and folding endurance were increased by 7.0%, 16.9%, and 102.3%, respectively, compared to the control. With increasing of oxidation time, the paper strength increased first and then decreased, reaching the maximum in 60 min. In addition, OKG can improve the properties of recycled paper more significantly. When the pH of paper making system was 7, the tensile index, burst index, and folding endurance of the recycled paper were increased by 22.2%, 19.9%, 59.9%, respectively, compared to the control. SEM analysis showed that paper strengthening agent resulted in a more contiguous junction between the fibers in paper