Mannans are widespread hemicellulosic polysaccharides in plant cell walls. Hydrolysis of the internal beta-1,4-D: -mannopyranosyl linkage in the backbone of mannans is catalyzed by endo-beta-mannanase. Plant endo-beta-mannanase has been well studied for its function in seed germination. Its involvement in other plant biological processes, however, remains poorly characterized or elusive. The completed genome sequences of Arabidopsis (Arabidopsis thaliana), rice (Oryza sativa), and poplar (Populus trichocarpa) provide an opportunity to conduct comparative genomic analysis of endo-beta-mannanase genes in these three species. In silico sequence analysis led to the identification of eight, nine and 11 endo-beta-mannanase genes in the genomes of Arabidopsis, rice, and poplar, respectively. Sequence comparisons revealed the conserved amino acids and motifs that are critical for the active site of endo-beta-mannanases. Intron/exon structure analysis in conjunction with phylogenetic analysis implied that both intron gain and intron loss has played roles in the evolution of endo-beta-mannanase genes. The phylogenetic analysis that included the endo-beta-mannanases from plants and other organisms implied that plant endo-beta-mannanases have an ancient evolutionary origin. Comprehensive expression analysis of all Arabidopsis and rice endo-beta-mannanase genes showed divergent expression patterns of individual genes, suggesting that the enzymes encoded by these genes, while carrying out the same biochemical reaction, are involved in diverse biological processes.
To facilitate wheat breeding with the Ph1 gene, 19 sequence tagged‐polymerase chain reaction (STS‐PCR) primers developed previously from barley chromosome 5H were screened. One pair of STS‐PCR primers differentiated ‘Chinese Spring’ (CS, Ph1) and the CS mutant (ph1b). The diagnostic fragment was 920 base pairs (bp) in size, designated as ABC920, and was located on the interstitial deletion of the long arm of chromosome 5B of ph1b mutant. Plants with or without the Ph1 gene could be distinguished among 148 F2 / 97 BC1 plants from the cross CS (Ph1) × CS mutant (ph1b) on the basis of the presence or absence of this fragment. Subsequently, two 24‐mer sequence characterized amplified regions (SCAR) primers were developed on the basis of sequences at both ends of the ABC920 fragment to generate a single amplified band in plants with the Ph1 genotype. The Ph1 and ph1b genotypes can be readily scored in the PCR products of individual plant DNA. This SCAR marker (SCABC823) was used to facilitate the transfer of the ph1b locus into an elite wheat (Triticum aestivum L.) cultivar. This marker is expected to aid in gene transfer between wheat and its wild relatives.
Diverse
2,3-substituted indanones are accessed in an efficient
and robust protocol by a rhodium-catalyzed tandem carborhodium/cyclization
and intramolecular proton shift pathway. The reaction is compatible
with a broad range of functional internal acetylenes, especially for
natural and functionalized alkynes derivatives, affording the desired
indanones in good to excellent yields. Remarkably, this reaction features
very mild and sustainable conditions using water as the sole solvent
and without exogenous ligands. Control studies support that indanone
is formed through the intramolecular proton transfer process from
the key intermediate indenol.
Fungi work as decomposers to break down organic carbon, deposit recalcitrant carbon, and transform other elements such as nitrogen. The decomposition of biomass is a key function of wood-decaying basidiomycetes and ascomycetes, which have the potential for the bioremediation of hazardous chemicals present in the environment. Due to their adaptation to different environments, fungal strains have a diverse set of phenotypic traits. This study evaluated 320 basidiomycetes isolates across 74 species for their rate and efficiency of degrading organic dye. We found that dye-decolorization capacity varies among and within species. Among the top rapid dye-decolorizing fungi isolates, we further performed genome-wide gene family analysis and investigated the genomic mechanism for their most capable dye-degradation capacity. Class II peroxidase and DyP-type peroxidase were enriched in the fast-decomposer genomes. Gene families including lignin decomposition genes, reduction-oxidation genes, hydrophobin, and secreted peptidases were expanded in the fast-decomposer species. This work provides new insights into persistent organic pollutant removal by fungal isolates at both phenotypic and genotypic levels.
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