Bambusa pervariabilis × Dendrocalamopisis grandis blight is caused by a toxin produced by the fungus Arthrinium phaeospermum. In this study, a toxin fraction (P1-2-2) with an estimated molecular mass of 31 kDa was purified from a culture filtrate of this fungus by ammonium sulfate precipitation, Sephadex G-50 gel chromatography, Q Sepharose Fast Flow anion exchange resin, and Sephadex G-75 chromatography. The N-terminal amino acid sequence (i.e., H(2)N-Gln-Val-Arg-Asp-Arg-Leu-Glu-Ser-Thr) determined by Edman degradation showed homology to known serine alkaline proteases. The purified protein was named AP-toxin. Effects of the purified protein toxin on total phenol, flavonoid, total nucleic acid, DNA, RNA, soluble protein, and soluble sugar content, as well as DNase and RNase activities and disease index, were analyzed in different bamboo varieties by the impregnation method. The toxin had a significant effect on each parameter tested. In addition, a significant correlation was observed among the metabolic index, treatment time, bamboo resistance, and disease index. These data suggest that AP-toxin plays an important role in mediating the phytotoxic activities of A. phaeospermum. This study also indicates that metabolic indices could reflect the resistance indices of hybrid bamboo to blight.

The present study demonstrated that the chitinase gene ChiKJ406136 of Streptomyces sampsonii (Millard & Burr) Waksman KJ40 could be cloned using a PCR protocol and expressed in Escherichia coli (Migula) Castellani & Chalmers BL21 (DE3), and the recombinant protein had antifungal effect on four forest pathogens (Cylindrocladium scoparium Morgan, Cryphonectria parasitica (Murrill) Barr, Neofusicoccum parvum Crous, and Fusarium oxysporum Schl.) and also had the biological control effects on Eucalyptus robusta Smith leaf blight, Castanea mollissima BL. blight, Juglans regia L. blight and J. regia root rot. The results showed that ChiKJ406136 was efficiently expressed and a 48 kilodalton (kDa) recombinant protein was obtained. No significant change in protein production was observed in the presence of different concentrations of IPTG (isopropyl-b-D-thio-galactoside). The purified protein yield was greatest in the 150 mmol/L imidazole elution fraction, and the chitinase activities of the crude protein and purified protein solutions were 0.045 and 0.033 U/mL, respectively. The antifungal effects indicated that mycelial cells of the four fungi were disrupted, and the control effects of the chitinase on four forest diseases showed significant differences among the undiluted 10-and 20-fold dilutions and the control. The undiluted solution exhibited best effect. The results of this study provide a foundation for the use of S. sampsonii as a biocontrol agent and provides a new source for the chitinase gene, providing a theoretical basis for its application. & Grigoraki, Trichophyton sp. (Castell.) Sabour. [18] and Rhizoctonia violacea (Tul.) Pat. [20]. Previous studies demonstrated that the bioactive compounds of S. sampsonii have important applications in various fields [3]. For example, crude extracts showed antitumor activity against glioblastoma multiforme (GBM) cells, inhibiting cell growth by 70.04% [25], and the supernatant of a S. sampsonii culture showed biological activity against the root-knot nematode [26]. In the purified components, soil isolates of S. sampsonii can produce heptaene polyene antibiotics [18,27], In addition, S. sampsonii has been shown to produce hydrolytic enzymes, such as amylase, chitinase, protease, and lipase [19]. Studies at the molecular level have focused on strain identification and the phylogenesis of related species [28][29][30][31][32][33][34][35]. The complete genome sequence of Streptomyces sampsonii KJ40 was recently described by our lab [36], resulting in the discovery of a large number of gene encoding chitinases and enzymes involved in secondary metabolite production. However, little is known regarding the metabolic pathways and genetic regulation in this strain, limiting its practical application.Chitin, a linear polymer of β-1,4-glucosidicosamine (GlcNAC), is the second most abundant polysaccharide in nature. Chitin can be degraded by chitinolytic enzymes, that is chitinase. Chitinases (EC 3.2.1.14) are widely present in a great variety of organisms, including insects, fungi,...

Bambusa pervariabilis McClure × Dendrocalamopsis grandis (Q.H.Dai & X.l.Tao ex Keng f.) Ohrnb. blight is a widespread and dangerous forest fungus disease, and has been listed as a supplementary object of forest phytosanitary measures. In order to study the control of B. pervariabilis × D. grandis blight, this experiment was carried out. In this work, a toxin purified from the pathogen Arthrinium phaeospermum (Corda) Elli, which causes blight in B. pervariabilis × D. grandis, with homologous heterogeneity, was used as an inducer to increase resistance to B. pervariabilis × D. grandis. A functional analysis of the differentially expressed proteins after induction using a tandem mass tag labeling technique was combined with mass spectrometry and liquid chromatography mass spectrometry in order to effectively screen for the proteins related to the resistance of B. pervariabilis × D. grandis to blight. After peptide labeling, a total of 3320 unique peptides and 1791 quantitative proteins were obtained by liquid chromatography mass spectrometry analysis. Annotation and enrichment analysis of these peptides and proteins using the Gene ontology and Kyoto Encyclopedia of Genes and Genomes databases with bioinformatics software show that the differentially expressed protein functional annotation items are mainly concentrated on biological processes and cell components. Several pathways that are prominent in the Kyoto Encyclopedia of Genes and Genomes annotation and enrichment include metabolic pathways, the citrate cycle, and phenylpropanoid biosynthesis. In the Protein-protein interaction networks four differentially expressed proteins-sucrose synthase, adenosine triphosphate-citrate synthase beta chain protein 1, peroxidase, and phenylalanine ammonia-lyase significantly interact with multiple proteins and significantly enrich metabolic pathways. To verify the results of tandem mass tag, the candidate proteins were further verified by parallel reaction monitoring, and the results were consistent with the tandem mass tag data analysis results. It is confirmed that the data obtained by tandem mass tag technology are reliable. Therefore, the differentially expressed proteins and signaling pathways discovered here is the primary concern for subsequent disease resistance studies.

In this study, TMT (tandem mass tag)-labeled quantitative protein technology combined with LC–MS/MS (liquid chromatography-mass spectrometry/mass spectrometry) was used to isolate and identify the proteins of the hybrid bamboo (Bambusa pervariabilis × Dendrocalamopsis grandis) and the bamboo inoculated with the pathogenic fungi Arthrinium phaeospermum. A total of 3320 unique peptide fragments were identified after inoculation with either A. phaeospermum or sterile water, and 1791 proteins were quantified. A total of 102 differentially expressed proteins were obtained, of which 66 differential proteins were upregulated and 36 downregulated in the treatment group. Annotation and enrichment analysis of these peptides and proteins using the GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) databases with bioinformatics software showed that the differentially expressed protein functional annotation items were mainly concentrated on biological processes and cell components. The LC–PRM/MS (liquid chromatography-parallel reaction monitoring/mass spectrometry) quantitative analysis technique was used to quantitatively analyze 11 differential candidate proteins obtained by TMT combined with LC–MS/MS. The up–down trend of 10 differential proteins in the PRM results was consistent with that of the TMT quantitative analysis. The coincidence rate of the two results was 91%, which confirmed the reliability of the proteomic results. Therefore, the differentially expressed proteins and signaling pathways discovered here may be the further concern for the bamboo-pathogen interaction studies.

Phytoremediation is considered to be a promising approach to restore or stabilize soil contaminated by lead (Pb). Turfgrasses, due to their high biomass yields, are considered to be suitable for use in phytoextraction of soil contaminated with heavy metal. It has been demonstrated that centipedegrass (Eremochloa ophiuroides (Munro) Hack., Poaceae) is a good turfgrass for restore of soil contaminated by Pb. However, the enhanced tolerant mechanisms in metallicolous (M) centipedegrass accessions remain unknown. In this study, we made a comparative study of growth performance, Pb accumulation, antioxidant levels, and phytochelatin concentrations in roots and shoots from M and nonmetallicolous (NM) centipedegrass accessions. Results showed that turf quality and growth rate were less repressed in M accessions than in NM accession. Pb stress caused generation of reactive oxygen species in centipedegrass with relatively lower levels in M accessions. Antioxidant activity analysis indicated that superoxide dismutase and catalase played important roles in Pb tolerance in M accessions. M accessions accumulated more Pb in roots and shoots. Greatly increased phytochelatins and less repressed sulfur contents in roots and shoots of M accessions indicated that they correlated with Pb accumulation and tolerance in centipedegrass.

Neofusicoccum parvum can cause stem and branch blight of walnut (Juglans spp.), resulting in great economic losses and ecological damage. A total of two strains of N. parvum were subjected to RNA-sequencing after being fed on different substrates, sterile water (K1/K2), and walnut (T1/T2), and the function of ABC1 was verified by gene knockout. There were 1,834, 338, and 878 differentially expressed genes (DEGs) between the K1 vs. K2, T1 vs. K1, and T2 vs. K2 comparison groups, respectively. The expression changes in thirty DEGs were verified by fluorescent quantitative PCR. These thirty DEGs showed the same expression patterns under both RNA-seq and PCR. In addition, ΔNpABC1 showed weaker virulence due to gene knockout, and the complementary strain NpABC1c showed the same virulence as the wild-type strain. Compared to the wild-type and complemented strains, the relative growth of ΔNpABC1 was significantly decreased when grown with H2O2, NaCl, Congo red, chloramphenicol, MnSO4, and CuSO4. The disease index of walnuts infected by the mutants was significantly lower than those infected by the wild-type and complementary strains. This result indicates that ABC1 gene is required for the stress response and virulence of N. parvum and may be involved in heavy metal resistance.

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