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The genus Asparagus arose ∼9 to 15 million years ago (Ma), and transitions from hermaphroditism to dioecy (separate sexes) occurred ∼3 to 4 Ma. Roughly 27% of extant Asparagus species are dioecious, while the remaining are bisexual with monoclinous flowers. As such, Asparagus is an ideal model taxon for studying the early stages of dioecy and sex chromosome evolution in plants. Until now, however, understanding of diversification and shifts from hermaphroditism to dioecy in Asparagus has been hampered by the lack of robust species tree estimates for the genus. In this study, a genus-wide phylogenomic analysis including 1,726 nuclear loci and comprehensive species sampling supports two independent origins of dioecy in Asparagus —first in a widely distributed Eurasian clade and then in a clade restricted to the Mediterranean Basin. Modeling of ancestral biogeography indicates that both dioecy origins were associated with range expansion out of southern Africa. Our findings also reveal several bursts of diversification across the phylogeny, including an initial radiation in southern Africa that gave rise to 12 major clades in the genus, and more recent radiations that have resulted in paraphyly and polyphyly among closely related species, as expected given active speciation processes. Lastly, we report that the geographic origin of domesticated garden asparagus (Asparagus officinalis L.) was likely in western Asia near the Mediterranean Sea. The presented phylogenomic framework for Asparagus is foundational for ongoing genomic investigations of diversification and functional trait evolution in the genus and contributes to its utility for understanding the origin and early evolution of dioecy and sex chromosomes. [ABSTRACT FROM AUTHOR]

Background: Asparagus L., widely distributed in the old world is a genus under Asparagaceae, Asparagales. The species of the genus were mainly used as vegetables, traditional medicines as well as ornamental plants. However, the evolution and functions of mitochondrial (Mt) genomes (mitogenomes) remains largely unknown. In this study, the typical herbal medicine A. taliensis and ornamental plant A. setaceus were used to assemble and annotate the mitogenomes, and the resulting mitogenomes were further compared with published mitogenome of A. officinalis for the analysis of their functions in the context of domestication and adaptative evolution. Results: The mitochondrial genomes of both A. taliensis and A. setaceus were assembled as complete circular ones. The phylogenetic trees based on conserved protein-coding genes of Mt genomes and whole chloroplast (Cp) genomes showed that, the phylogenetic relationship of the sampled 13 species of Asparagus L. were not exactly consistent. The collinear analyses between the nuclear (Nu) and Mt genomes confirmed the existence of mutual horizontal genes transfers (HGTs) between Nu and Mt genomes within these species. Based on RNAseq data, the Mt RNA editing were predicted and atp1 and ccmB RNA editing of A. taliensis were further confirmed by DNA sequencing. Simultaneously homologous search found 5 Nu coding gene families including pentatricopeptide-repeats (PPRs) involved in Mt RNA editing. Finally, the Mt genome variations, gene expressions and mutual HGTs between Nu and Mt were detected with correlation to the growth and developmental phenotypes respectively. The results suggest that, both Mt and Nu genomes co-evolved and maintained the Mt organella replication and energy production through TCA and oxidative phosphorylation. Conclusion: The assembled and annotated complete mitogenomes of both A. taliensis and A. setaceus provide valuable information for their phylogeny and concerted action of Nu and Mt genomes to maintain the energy production system of Asparagus L. in the context of domestication and adaptation to environmental niches. Highlights: Mitochondrial genomes of A. taliensis and A. setaceus were assembled and annotated, and phylogenetic trees of 13 sampled species in the genus Asparagus based on both mitochondrial and chloroplast genomes showed that A. officinalis, A. taliensis and A. setaceus are represented species of Asparagus L. Independent horizontal gene transfers (HGTs) between the mitochondrial and nuclear genomes were detected with reduction in dioecious species, while Mt RNA editing rate was higher in dioecious species with consistency of their higher copies and higher expression levels of involved nuclear coding RNA editing enzyme genes. Detected different gene copies and expression levels of both pathways of tricarboxylic acid cycle(TCA) and oxidative phosphorylation genes indicates the different efficiency of citric acid accumulation and ATP synthesis due to adaptation and/or domestication among species of A. officinalis, A. taliensis and A. setaceus. [ABSTRACT FROM AUTHOR]

Sex chromosomes evolved from autosomes many times across the eukaryote phylogeny. Several models have been proposed to explain this transition, some involving male and female sterility mutations linked in a region of suppressed recombination between X and Y (or Z/W, U/V) chromosomes. Comparative and experimental analysis of a reference genome assembly for a double haploid YY male garden asparagus (Asparagus officinalis L.) individual implicates separate but linked genes as responsible for sex determination. Dioecy has evolved recently within Asparagus and sex chromosomes are cytogenetically identical with the Y, harboring a megabase segment that is missing from the X. We show that deletion of this entire region results in a male-to-female conversion, whereas loss of a single suppressor of female development drives male-to-hermaphrodite conversion. A single copy anther-specific gene with a male sterile Arabidopsis knockout phenotype is also in the Y-specific region, supporting a two-gene model for sex chromosome evolution.

Tomato/potato heterografting‐triggered phenotypic variations are well documented, yet the molecular mechanisms underlying grafting‐induced phenotypic processes remain unknown. To investigate the phenotypic and transcriptomic responses of grafting parents in heterografting in comparison with self‐grafting, tomato (Sl) was grafted onto potato rootstocks (St), and comparative phenotyping and transcriptome profiling were performed. Phenotypic analysis showed that Sl/St heterografting induced few phenotypic changes in the tomato scion. A total of 209 upregulated genes were identified in the tomato scion, some of which appear to be involved in starch and sucrose biosynthesis. Sl/St heterografting induced several modifications in the potato rootstocks (St‐R), stolon number, stolon length and tuber number decreased significantly, together with an increase in GA3 content of stolon and tuber, compared with self‐grafted potato (St‐WT). These results indicate that the tomato scion is less effective at producing substances or signals to induce tuberization but promotes stolon development into aerial stems and sprouting. RNA‐Seq data analysis showed that 1529 genes were upregulated and 1329 downregulated between St‐WT and St‐R; some of these genes are involved in plant hormone signal transduction, with GID1‐like gibberellin receptor (StGID1) and DELLA protein (StDELLA) being upregulated. Several genes in auxin, abscisic acid and ethylene pathways were differentially expressed as well. Various hormone signals engage in crosstalk to regulate diverse phenotypic events after grafting. This work provides abundant transcriptome profile data and lays a foundation for further research on the molecular mechanisms underlying RNA‐based interactions between rootstocks and scions after tomato/potato heterografting. [ABSTRACT FROM AUTHOR]

Northern corn leaf spot, a foliar disease caused by Cochliobolus carbonum, has become prevalent in southwestern China, especially in the Yunnan Province. Races and mating types were identified for 169 isolates collected from 13 prefectures of Yunnan by artificial inoculation using six hybrid corns as differential hosts and by crossing with three standard mating strains: CC092 ( MAT1-2), CC120 ( MAT1-1) and CC026 ( MAT1-1). Results showed the existence of three races: CCR1 (one isolate), CCR2 (43 isolates) and CCR3 (125 isolates). Most isolates were moderately or weakly virulent with only five being highly virulent. CCR3 was widely distributed and significantly more virulent than CCR2 that coexisted with CCR3 in many locations. On Sach's nutrient agar, 20.71% of the Yunnan isolates self-mated, forming sterile perithecia. Fully developed perithecia could be formed between isolates of different geographic origins, but only 15.98% strains mated successfully with CC092 and 5.33% formed mature perithecia with 4-6 ascospores per asus. Similar results were obtained in crossing with CC026 or CC120. Mating could also occur between CCR3 and CCR2. Both mating types were found in Yunnan with 84 MAT1-1 strains (one CCR1, 10 CCR2 and 73 CCR3) and 85 MAT1-2 strains (33 CCR2 and 52 CCR3) and they coexisted in most areas. To identify the mating type rapidly, three specific primers were successfully developed and employed to amplify the mating-type genes, with stable patterns of 1627 and 876 bp fragments obtained from MAT1-1 and MAT1-2 isolates, respectively. The ratio between MAT1-1 and MAT1-2 was 1 : 1, indicating that the mating-type genes segregated randomly in the field naturally. [ABSTRACT FROM AUTHOR]

Abstract: The plant-associated Bacillus amyloliquefaciens subsp. plantarum strain B9601-Y2, isolated from wheat rhizosphere, is a powerful plant growth-promoting rhizobacterium. Its relative large genome size of 4.24Mbp, exceeding that of other representatives of the B. amyloliquefaciens subsp. plantarum taxon, is mainly due to the presence of 18 DNA-islands containing remnants of phages, a unique restriction modification system, a gene cluster for mersacidin synthesis, and an orphan gene cluster devoted to non-ribosomal synthesis of an unidentified peptide. Like other members of the taxon, the Y2 genome contains giant gene clusters for non-ribosomal synthesis of the polyketides macrolactin, difficidin, and bacillaene, the antifungal lipopeptides bacillomycin D, and fengycin, the siderophore bacillibactin, and the dipeptide bacilysin. A gene cluster encoding enzymes for a degradative pathway with 2-keto-3-deoxygluconate and 2-keto-3-deoxy-phosphogluconate as intermediates was explored by genome mining and found as being a unique feature for representatives of the plantarum subspecies. A survey of the Y2 genome against other B. amyloliquefaciens genomes revealed 130 genes only occurring in subsp. plantarum but not in subsp. amyloliquefaciens. Notably, the surfactin gene cluster is not functional due to a large deletion removing parts of the Srf synthetases B and C. Expression of polyketides, lipopeptides, mersacidin, and of the growth hormone indole-3-acetic acid in Y2 was demonstrated by matrix-assisted laser desorption ionization-time of flight mass spectroscopy and high-performance liquid chromatography, respectively. [Copyright &y& Elsevier]

The synthetic pathways of some phenolics compounds in asparagus have been reported, however, the diversified phenolics compounds including their modification and transcription regulation remains unknown. Thus, multi-omics strategies were applied to detect the phenolics profiles, contents, and screen the key genes for phenolics biosynthesis and regulation in asparagus. A total of 437 compounds, among which 204 phenolics including 105 flavonoids and 82 phenolic acids were detected with fluctuated concentrations in roots (Rs), spears (Ss) and flowering twigs (Fs) of the both green and purple cultivars. Based on the detected phenolics profiles and contents correlated to the gene expressions of screened synthetic enzymes and regulatory TFs, a full phenolics synthetic pathway of asparagus was proposed for the first time, essential for future breeding of asparagus and scaled healthy phenolics production using synthetic biological strategies., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Zichao Mao reports financial support was provided by Yunnan Provincial Science and Technology Department and Sichuan Provincial Science and Technology Department., (© 2023 The Author(s).)

Zymomonas mobilis is a superb ethanol producer with productivity exceeding yeast strains by several fold. Although metabolic engineering was successfully applied to expand its substrate range to include xylose, xylose fermentation lagged far behind glucose. In addition, xylose fermentation was often incomplete when its initial concentration was higher than 5%. Improvement of xylose fermentation is therefore necessary. In this work, we applied adaptation to improve xylose fermentation in metabolically engineered strains. As a result of adaptation over 80 days and 30 serial transfers in a medium containing high concentration of xylose, a strain, referred as A3, with markedly improved xylose metabolism was obtained. The strain was able to grow on 10% (w/v) xylose and rapidly ferment xylose to ethanol within 2 days and retained high ethanol yield. Similarly, in mixed glucose-xylose fermentation, a total of 9% (w/v) ethanol was obtained from two doses of 5% glucose and 5% xylose (or a total of 10% glucose and 10% xylose). Further investigation reveals evidence for an altered xylitol metabolism in A3 with reduced xylitol formation. Additionally xylitol tolerance in A3 was increased. Furthermore, xylose isomerase activity was increased by several times in A3, allowing cells to channel more xylose to ethanol than to xylitol. Taken together, these results strongly suggest that altered xylitol metabolism is key to improved xylose metabolism in adapted A3 strain. This work further demonstrates that adaptation and metabolic engineering can be used synergistically for strain improvement., (Copyright © 2010 Wiley Periodicals, Inc.)

A xylosidase gene, labeled as BH1068 in genome of Bacillus halodurans C-125, was successfully cloned and overexpressed in Escherichia coli JM109. The purified enzyme was thoroughly characterized and its xylosidase function was unambiguously confirmed. It has maximum activities in neutral condition and is stable over a wide range of pH (4.5-9.0). The enzyme has a broad temperature optimal (35 degrees C-45 degrees C) and is quite stable at temperature up to 45 degrees C. The unique pH and temperature profiles of the enzyme should allow a wide range of xylanolytic operational conditions. With high specific activity of 174 mU/mg protein for its artificial substrate (p-nitrophenyl-beta-xylose) and low xylose inhibition (inhibitor constant Ki = 300 mmol/L), this enzyme is among the most active and high tolerant bacterial xylosidase to xylose inhibition. Its high synergy with commercial xylanase has been demonstrated with beechwood xylan hydrolysis, achieving a hydrolysis yield of 40%. Its neutral pH optimal and high tolerance to product inhibition complements well with its fungal counterparts that are only optimal at acidic pH and susceptible to xylose inhibition. In conclusion, this enzyme has high potential in the saccharification of xylan and xylan-containing polysaccharides.