Optimizing the Mulching Pattern and Nitrogen Application Rate to Improve Maize Photosynthetic Capacity, Yield, and Nitrogen Fertilizer Utilization Efficiency.

Residual film pollution and excessive nitrogen fertilizer have become limiting factors for agricultural development. To investigate the feasibility of replacing conventional plastic film with biodegradable plastic film in cold and arid environments under nitrogen application conditions, field experiments were conducted from 2021 to 2022 with plastic film covering (including degradable plastic film (D) and ordinary plastic film (P)) combined with nitrogen fertilizer 0 (N0), 160 (N1), 320 (N2), and 480 (N3) kg·ha-1. The results showed no significant difference (p > 0.05) in dry matter accumulation, photosynthetic gas exchange parameters, soil enzyme activity, or yield of spring maize under degradable plastic film cover compared to ordinary plastic film cover. Nitrogen fertilizer is the main factor limiting the growth of spring maize. The above-ground and root biomass showed a trend of increasing and then decreasing with the increase in nitrogen application level. Increasing nitrogen fertilizer can also improve the photosynthetic gas exchange parameters of leaves, maintain soil enzyme activity, and reduce soil pH. Under the nitrogen application level of N2, the yield of degradable plastic film and ordinary plastic film coverage increased by 3.74~42.50% and 2.05~40.02%, respectively. At the same time, it can also improve water use efficiency and irrigation water use efficiency, but it will reduce nitrogen fertilizer partial productivity and nitrogen fertilizer agronomic use efficiency. Using multiple indicators to evaluate the effect of plastic film mulching combined with nitrogen fertilizer on the comprehensive growth of spring maize, it was found that the DN2 treatment had the best complete growth of maize, which was the best model for achieving stable yield and income increase and green development of spring maize in cold and cool irrigation areas.

Exogenous γ-Aminobutyric Acid (GABA) Enhanced Response to Abiotic Stress in Hypsizygus marmoreus by Improving Mycelial Growth and Antioxidant Capacity.

γ-Aminobutyric (GABA) acid is a nutrient and signaling molecule existing in many plants, participating in the regulation of metabolism and various physiological activities. Two strains of Hypsizygus marmoreus (a white variety and a brown variety) were investigated to study the impact of exogenous GABA on mycelial growth and the response to stress. Mycelial growth, microscopic morphology, antioxidant profile, and gad2 expression in H. marmoreu were investigated under salt, dehydration, or cold stress. The results indicated that 5 mM GABA stimulated mycelial growth under standard cultivation conditions, whereas GABA addition over 10 mM hindered the growth. Under salt, dehydration, or cold stress, treatment with 5 mM GABA significantly enhanced the mycelial growth rate and density of both H. marmoreus strains by promoting front hyphae branching. Meanwhile, the activities of key antioxidant enzymes such as peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) were enhanced by GABA, thereby augmenting the defensive network against abiotic stress. Additionally, gad2 expression and GABA concentration were increased under abiotic stresses as a resistance regulation response. The exogenous addition of GABA strengthened the upregulation of gad2 expression and GABA production. These findings indicated that exogenously adding low concentrations of GABA effectively enhanced the mycelial growth and antioxidant profile of H. marmoreus, thereby improving its resistance against stresses.

Selection and validation of internal control genes for quantitative real-time RT‒qPCR normalization of Phlebopus portentosus gene expression under different conditions.

Phlebopus portentosus (Berk. and Broome) Boedijn is an attractive edible mushroom and is considered the only bolete for which artificial cultivation in vitro has been achieved. Gene expression analysis has become widely used in research on edible fungi and is important for elucidating the functions of genes involved in complex biological processes. Selecting appropriate reference genes is crucial to ensuring reliable RT‒qPCR gene expression analysis results. In our study, a total of 12 candidate control genes were selected from 25 traditional housekeeping genes based on their expression stability in 9 transcriptomes of 3 developmental stages. These genes were further evaluated using geNorm, NormFinder, and RefFinder under different conditions and developmental stages. The results revealed that MSF1 domain-containing protein (MSF1), synaptobrevin (SYB), mitogen-activated protein kinase genes (MAPK), TATA-binding protein 1 (TBP1), and SPRY domain protein (SPRY) were the most stable reference genes in all sample treatments, while elongation factor 1-alpha (EF1), actin and ubiquitin-conjugating enzyme (UBCE) were the most unstably expressed. The gene SYB was selected based on the transcriptome results and was identified as a novel reference gene in P. portentosus. This is the first detailed study on the identification of reference genes in this fungus and may provide new insights into selecting genes and quantifying gene expression.

Optimizing water and nitrogen management strategies to improve their use efficiency, eggplant yield and fruit quality.

With improvement in living standards, consumer preferences for vegetables are changing from quantity- to quality-oriented. Water and nitrogen supply, as two major determinants of vegetable crop yield and quality, can be optimally managed to improve the yield and quality. To evaluate the response in yield, fruit quality, and water and nitrogen utilization of eggplant to different water and nitrogen management strategies, a 2-year (2021 and 2022) field trial under mulched drip irrigation was conducted. The growth period was divided into seedling, flowering and fruit set, fruit development, and fruit ripening stages. Three irrigation levels were applied during the flowering and fruit set stage: W0, adequate water supply (70%-80% of field water capacity, FC); W1, mild water deficit (60%-70% FC); and W2, moderate water deficit (50%-60% FC). In addition, three nitrogen application rates were applied: N1, low nitrogen level (215 kg ha-1); N2, medium nitrogen level (270 kg ha-1); and N3, high nitrogen level (325 kg ha-1). The irrigation and nitrogen rates were applied in all combinations (i.e., nine treatments in total). Adequate water supply throughout the reproductive period in combination with no nitrogen application served as the control (CK). The yield of the W1N2 treatment was significantly increased by 32.62% and 35.06% in 2021 and 2022, respectively, compared with that of the CK. Fruit soluble protein, soluble solids, and vitamin C contents were significantly higher under W1 than W2. Fruit quality was significantly higher under the N2 rate compared with the other nitrogen rates. The W1N2 treatment showed the highest water productivity, with a significant increase of 11.27%-37.84% (2021) and 14.71%-42.48% (2022) compared with that under the other treatments. Based on the average water-deficit degree and nitrogen application rate, W0 and N1 had the highest partial factor productivity of nitrogen. Assessment of the results using the TOPSIS (technique for order preference by similarity to an ideal solution) method indicated that mild water deficit in combination with the medium nitrogen application rate (W1N2) was the optimal water and nitrogen management strategy for cultivated eggplant. The present findings contribute novel insights into the sustainable cultivation of eggplant in an oasis arid environment.

Deficit mulched drip irrigation improved yield and quality while reduced water consumption of isatis indigotica in a cold and arid environment.

Deficit irrigation is an effective alternative to traditional irrigation, as it improves crop productivity and conserves water. However, crops may be sensitive to deficit irrigation-induced water stress at different periods. To access the effect of deficit irrigation on the growth, water consumption characteristics, yield, and quality of Isatis indigotica (woad), we performed a three-year (2017-2019) mulched drip irrigation field experiment. Woad plants were provided adequate water supply at the seedling stage but were subjected to mild (65-75% field water capacity FC), moderate (55-65% FC), and severe (45-55% FC) water deficit at the vegetative growth, fleshy root growth and fleshy root maturity stages, respectively; plants supplied with adequate water throughout the growth period served as a control (CK, 75-85% FC). The water consumption characteristics, agronomic traits, dry matter content and distribution, yield, and quality of these plants were measured at various growth stages. The results showed that the total water consumption in water deficit was significantly less than that in CK by 4.44-10.21% (P< 0.05). The dry matter content of plants treated with moderate (WT2 and WT5) and severe (WT3) water deficit was reduced by 12.83-28.75%. The economic yield of mild water deficit-treated plants was higher during vegetative growth (WT1) and fleshy root growth (WT4), while the water use efficiency of these plants was significantly increased by 7.84% and 6.92% at the two growth stages, respectively. Continuous mild water deficit (WT4) enhanced the contents of indigo, indirubin, (R,S)-goitrin, polysaccharides, and soluble proteins during vegetative growth and fleshy root growth, while moderate and severe water deficit were detrimental to the quality of woad plants. Thus, continuous mild water deficit during vegetative and fleshy root growth periods (WT4) is optimal for the cultivation of woad in the cold and cool irrigation district of the Hexi Oasis region.

Physiological and biochemical responses of Isatis indigotica to deficit irrigation in a cold and arid environment.

Water shortage and wastage are critical challenges to sustainable agricultural development, especially in arid and semiarid regions worldwide. Isatis indigotica (woad), as a traditional Chinese herb, was planted in a large area in a cold and arid environment of Hexi. Regulated deficit irrigation can reduce the growth of some vegetative organs by changing the accumulation and distribution of photosynthetic products in crops, thus increasing the economic yield of crops. In agricultural production, crop productivity may be improved by mulched drip irrigation and deficit irrigation. Hence, a field experiment was conducted to investigate the responses of photosynthesis, malondialdehyde, osmotic regulators, antioxidant enzyme activities, and the yield of woad to water deficit at different growth stages. The growth stage of woad was divided in four stages: seedling, vegetative growth, fleshy root growth, and fleshy root maturity. During vegetative growth, fleshy root growth, and fleshy root maturity, three water gradients were set for plants with mild (65-75% in field water capacity, FC), moderate (55-65% in FC), and severe (45-55% in FC) deficits, respectively. In contrast, an adequate water supply (75-85% in FC) during the growth period was designed as the control (CK). The net photosynthetic rate (Pn), transpiration rate, and stomatal conductance of woad significantly decreased (P< 0.05) by moderate and severe water deficits. Still, rehydration after the water deficit could produce a noticeable compensation effect. In contrast, malondialdehyde and proline accumulation significantly increased under moderate and severe water deficits. At the same time, the superoxide dismutase, peroxidase, and catalase all had high activities (increased significantly by 19.87-39.28%, 19.91-34.26%, and 10.63-16.13% compared with CK, respectively), but yields were substantially lower, compared to CK. Additionally, the net photosynthetic rate was negatively correlated with antioxidant enzyme activity. The economic yield of plants subjected to continuous mild water deficit during both vegetative and fleshy root growth was not significantly different from that in CK. Still, the water use efficiency improved significantly. Therefore, the continuous mild water deficit during vegetative and fleshy root growth could improve the physiological and biochemical mechanisms of the plant, representing an optimal irrigation strategy for woad in cold and arid areas.

Characterizing Mat Formation of Bamboo Fiber Composites: Horizontal Density Distribution.

Bamboo fiber composite (BFC) is a unidirectional and continuous bamboo fiber composite manufactured by consolidation and gluing of flattened, partially separated bamboo culm strips into thick and dense panels. The composite mechanical properties are primarily influenced by panel density, its variation and uniformity. This paper characterized the horizontal density distribution (HDD) within BFC panels and its controlling factors. It revealed that HDD follows a normal distribution, with its standard deviation (SD) strongly affected by sampling specimen size, panel thickness and panel locations. SD was lowest in the thickest (40 mm) panel and largest-size (150 × 150-mm2) specimens. There was also a systematic variation along the length of the BFC due to the tapering effect of bamboo culm thickness. Density was higher along panel edges due to restraint from the mold edges during hot pressing. The manual BFC mat forming process is presented and found to effectively minimize the density variation compared to machine-formed wood composites. This study provides a basic understanding of and a quality control guide to the formation uniformity of BFC products.

Agrobacterium-mediated transformation of arthroconidia obtained from the edible mushroom Hypsizygus marmoreus.

Using the carboxin resistance gene from Pleurotus eryngii as a selective marker, we introduced foreign DNA into the arthroconidia of Hypsizygus marmoreus through Agrobacterium-mediated transformation. The function of the exogenous GUS (ß-glucuronidase) gene driven by the CaMV35S promoter was detected in the transformants.

Three complete mitochondrial genomes of straw-rotting edible fungus Volvariella volvacea using next generation sequencing.

The straw-rotting edible fungus Volvariella volvacea is a widely cultivated edible fungus across China and Southeast Asian countries. Three complete mitochondrial genomes of V. volvacea from China, Thailand, and India were determined using the next-generation sequencing technology. The genome sizes of the three strains (China, Thailand, and India) were 62,541 bp, 64,531 bp, and 65,668 bp with GC contents of 38.46%, 38.56%, and 38.52%, respectively. All the genomes encoded 14 conserved protein-coding genes, the small ribosomal RNA subunits (rns), large ribosomal RNA subunits (rnl), and 23 tRNAs were located on the same strand. In the putative protein-coding genes, four introns were distributed in cox1 in the genomes of V23-1 and V8. 5 introns (four introns invaded into cox1and one intron invaded into cob) were detected in Tai8. The phylogenetic analysis confirmed that V. volvacea was a number of Agaricales. This mitochondrial genome may open new avenues for understanding the phylogeny and evolution of Pluteaceae and Agaricales.

The complete mitochondrial genome of the Basidiomycete edible fungus Hypsizygus marmoreus.

The complete mitochondrial genome of the edible fungus Hypsizygus marmoreus was published in this paper. It was determined using Pacbio and Illumina sequencing. The complete mitochondrial DNA (mtDNA) is 106,417 bp in length with a GC content of 31.74%, which was the fourth large mitogenome in Agaricales. The circular mitogenome encoded 67 protein-coding genes and one ribosomal RNAs (rns). Among these genes, 13 conserved protein-coding genes were determined in the genome, including 6 subunits of NAD dehydrogenase (nad1-4, 4L and 6), three cytochrome oxidases (cox1-3), one apocytochrome b (cob) and three ATP synthases (atp6, apt 8 and apt 9). The phylogenic analysis confirmed that H. marmoreus (Lyophyllaceae) clustered together with Tricholoma matsutake (Tricholomataceae).

Establishment of uracil auxotrophic dikaryotic strains of Lentinula edodes by crossbreeding.

The uracil auxotrophic monokaryotic strain 423-9 of Lentinula edodes was crossed with nine monokaryons (cro2-2-9, W66-1, xd2-3-2, QingKe 20A, 241-1-1, 9015-1, L66-2, 241-1-2, and Qing 23A) derived from wild type strains of L. edodes. Nine dikaryotic hybrids were established from these crosses. These hybrids were fruited and 496 single spore isolates were obtained. Among these single spore isolates, 166 were identified as monokaryons under a microscope. We screened these monokaryons on selective medium and obtained 19 uracil auxotrophic monokaryons. By using the Monkaryon-monkaryon crossing method among the uracil auxotrophic monokaryons, 56 uracil auxotrophic dikaryotic strains were established on selective medium. These dikaryotic strains were unable to grow on minimal medium without uracil and exhibited slow growth rates on PDA plates compared to the wild type strain. The uracil auxotrophic dikaryotic strains also showed more vigorous growth on sawdust cultivation medium containing uracil than that without uracil. The fruiting tests showed that they formed normal fruiting bodies on the sawdust medium containing uracil. The results show that the uracil auxotrophic dikaryotic strain of L. edodes could be produced by mating, and will provide a valuable resource for future genetic studies and for spawn protection and identification.

The genome of Pleurotus eryngii provides insights into the mechanisms of wood decay.

Pleurotus eryngii (DC.) Quél. is widely used for bioconverting lignocellulosic byproducts into biofuel and value added products. Sequencing and annotating the genome of a monokaryon strain P. eryngii 183 allows us to gain a better understanding of carbohydrate-active enzymes (CAZymes) and oxidoreductases for degradation of lignocellulose in white-rot fungi. The genomic data provides insights into genomic basis of degradation mechanisms of lignin and cellulose and may pave new avenues for lignocellulose bioconversion.

Discovery and Characterization of the Highly Active Fungal Immunomodulatory Protein Fip-vvo82.

Volvaria volvacea (Bull. ex Fr.) Sing, an important edible and medicinal macro-fungus, has been used to remedy various diseases for hundreds of years in East Asia. To identify key proteins with the unique therapeutic activity in V. volvacea, we conducted a genomewide comparison of V. volvacea protein families and those of other edible fungi that lack therapeutic functions and identified seven fungal immunomodulatory proteins (FIPs) in V. volvacea. On the basis of the predicted physiological and biochemical characteristics of the seven FIPs, the novel Fip-vvo82 was inferred to have high immunomodulatory activity; this was confirmed by molecular and immunological experiments and further characterized by modeling the three-dimensional structure and protein-protein docking. This is the first study to show that V. volvacea has more than one FIP.