Cytological studies reveal high variation in ascospore number and shape and conidia produced directly from ascospores in Morchella galilaea.

Spores are important as dispersal and survival propagules in fungi. In this study we investigated the variation in number, shape, size and germination mode of ascospores in Morchella galilaea, the only species of the genus Morchella known to fruit in the autumn. Based on the observation of five samples, we first discovered significant variation in the shape and size of ascospores in Morchella. One to sixteen ascospores were found in the asci. Ascospore size correlated negatively with ascospore number, but positively with ascus size, and ascus size was positively correlated with ascospore number. We noted that ascospores, both from fresh collections and dried specimens, germinated terminally or laterally either by extended germ tubes, or via the production of conidia that were formed directly from ascospores at one, two or multiple sites. The direct formation of conidia from ascospores takes place within asci or after ascospores are discharged. Using laser confocal microscopy, we recorded the number of nuclei in ascospores and in conidia produced from ascospores. In most ascospores of M. galilaea, several nuclei were observed, as is typical of species of Morchella. However, nuclear number varied from zero to around 20 in this species, and larger ascospores harbored more nuclei. One to six nuclei were present in the conidia. Nuclear migration from ascospores to conidia was observed. Conidia forming directly from ascospores has been observed in few species of Pezizomycetes; this is the first report of the phenomenon in Morchella species. Morphological and molecular data show that conidial formation from ascospores is not found in all the specimens of this species and, hence, is not an informative taxonomic character in M. galilaea. Our data suggest that conidia produced from ascospores and successive mitosis within the ascus may contribute to asci with more than eight spores. The absence of mitosis and/or nuclear degeneration, as well as cytokinesis defect, likely results in asci with fewer than eight ascospores. This study provides new insights into the poorly understood life cycle of Morchella species and more broadly improves knowledge of conidia formation and reproductive strategies in Pezizomycetes.

Pangenome analysis provides insight into the evolution of the orange subfamily and a key gene for citric acid accumulation in citrus fruits.

The orange subfamily (Aurantioideae) contains several Citrus species cultivated worldwide, such as sweet orange and lemon. The origin of Citrus species has long been debated and less is known about the Aurantioideae. Here, we compiled the genome sequences of 314 accessions, de novo assembled the genomes of 12 species and constructed a graph-based pangenome for Aurantioideae. Our analysis indicates that the ancient Indian Plate is the ancestral area for Citrus-related genera and that South Central China is the primary center of origin of the Citrus genus. We found substantial variations in the sequence and expression of the PH4 gene in Citrus relative to Citrus-related genera. Gene editing and biochemical experiments demonstrate a central role for PH4 in the accumulation of citric acid in citrus fruits. This study provides insights into the origin and evolution of the orange subfamily and a regulatory mechanism underpinning the evolution of fruit taste.

Primula luquanensis sp. nov. (Primulaceae), a New Species from Southwestern China, Reveals a Novel Floral Form in the Heterostyly-Prevailing Genus.

A new species, Primula luquanensis Z.K.Wu and Wei Zhou sp. nov. (Primulaceae) is described and illustrated from Yunnan Province, China. It is morphologically assigned to P. sect Aleuritia based on its dwarf and hairless habit and coverage by farina on both sides of the leaf blade and scape. This new species is similar to P. nutantiflora and P. yunnanensis, but it is easily distinguished by its stolons, solitary bract, bell-shaped corolla and monomorphic floral form. The new species also has a substantially reduced corolla tube, presenting a unique floral form in a genus where heterostyly typically prevails.

Vacciniumusneoides (Ericaceae), a new species from Yunnan, China.

Vacciniumusneoides (Ericaceae), a new species from Fugong County of Yunnan Province, China is described and illustrated. This new species belongs to Vacciniumsect.Calcicolus and is most similar to V.brachyandrum, but differs in its branches hanging down, much smaller leaf blades, shorter inflorescences and pedicels, non-glandular tomentellate or densely pubescent inflorescence rachis and pedicels, densely white-pubescent hypanthium and pilose filaments.

Vacciniummotuoense (Ericaceae), a new species from Xizang, China.

Vacciniummotuoense (Ericaceae), a new species from Motuo County, Xizang Autonomous Region, China is described and illustrated. This new species belongs to Vacciniumsect.Calcicolus and is morphologically most similar to V.dunalianum, but differs in having yellowish-brown tomentose young branches, petioles and inflorescence rachis, leaf blades with 2-3(-4) pairs of secondary veins, usually all basal and with fine veins impressed adaxially and urceolate to spherical corollas.

The complete chloroplast genome of a distylous-homostylous species, Primula homogama (Primulaceae).

Primula homogama F. H. Chen & C. M. Hu (Primulaceae) is endemic to the Emei Mountain of China. In this study, we characterized the complete chloroplast genome of P. homogama based on next-generation sequencing (NGS). The complete chloroplast genome of P. homogama was 154,677 bp in size with a typical quadripartite structure, containing a large single-copy (LSC) region of 85,299 bp and a small single-copy (SSC) region of 17,816 bp. These two regions were separated by a pair of inverted repeat regions (IRs), each of 25,781 bp. A total of 130 functional genes were encoded, consisted of 86 protein-coding genes (PCG), 36 tRNA genes, and eight ribosomal RNA (rRNA) genes.

The best choices: the diversity and functions of the plants in the home gardens of the Tsang-la (Motuo Menba) communities in Yarlung Tsangpo Grand Canyon, Southwest China.

BACKGROUND: Home garden is identified as a kind of small-scale land-use system which is used to manage and cultivate useful plants by local people, and home gardens can provide various plant products and services. Investigating home gardens was regarded as an effective way to understand the biodiversity-related local knowledge and culture of native people in Ethnobiology and Ethnoecology. Home garden is important in less developed and remote areas. The grand canyon of Yarlung Tsangpo is designed as one of the biodiversity hotspots of China, and it is one of the most remote regions of China, because of the rough traffic conditions. The aim of the present study is to collect, record, and document the plants and their local knowledge and functions in the local home gardens, then attempt to answer the question: "why local people selected these plants?" MATERIAL AND METHODS: The study area was in Beibeng Township of Motuo County in the grand canyon of Yarlung Tsangpo. Observation and semi-structure interviews with informed consent were used to collect data in field study. All information was collected and organized, then documented based on "ethno-species" as a fundamental unit. All of the information of local use and knowledge were organized as the list of "use-report" for quantitative analysis, and the local uses of plants were merged into 14 use categories. Frequency of citation (FC), relative frequency of citation (RFC), cultural importance index (CI), and cultural value index (CV) were used in quantitative analysis. Besides, the Jaccard Index was used to compare the similarity in plant species selection among different communities. RESULTS: A total of 78 home gardens in the 9 communities of Beibeng Township were visited, and 196 ethno-species were collected. These ethno-species were identified into 188 Botanical taxa. A total of 87 home garden owners as informants were interviewed in the present study, and they provided 625 use-reports to us. The top 5 important plants were Su-lan-tsao (Dendrobium nobile), Sa-ga (Zingiber officinale), Soe-lu (Capsicum annuum), Snying-pa (Citrus medica), and Kham-pu (Prunus persica), according to the quantitative analysis. The most citied use-category was "vegetable," followed by "ornamental plant," "medicine," and "fruit." The altitude might be the most important impact factor of the plant diversity and composition of home gardens, and the traffic conditions, local terrain, also impact the plant diversity and composition of home gardens. CONCLUSION: In remote areas such as the Yarlung Tsangpo Grand Canyon, the plants in home gardens are important sources of plant products such as foods, herbal medicines, and fibers to support daily lives. The local home gardens in Tsang-la communities had high diversity of plants, and these plants provided many functions and services to support daily lives of local people. Local plant knowledge, including the features, life forms, habits, habitats, and use values of plants, were the summary of the understanding of local people to their surrounding plant worlds. Local people selected appropriate plants to cultivate and manage in their home gardens under the guidance of the local plant knowledge. That is the answer to the question "why local people selected these plants?"

Bulbophyllum reflexipetalum (Orchidaceae, Epidendroideae, Malaxideae), a new species from Xizang, China.

Bulbophyllum reflexipetalum, a new species from Motuo County, Southeast Xizang, China, is described and illustrated here. This new species belongs to Bulbophyllum sect. Umbellata Bentham & J. D. Hooker, and it is morphologically similar to B. umbellatum Lindley, B. guttulatum (J. D. Hooker) N. P. Balakrishnan and B. salweenensis X.H. Jin, but is distinguished from them by having reflexed petals, base of dorsal sepal with 1 dentate on each side, lip with significantly revolute margin, adaxially with dark brown spots or patches and one longitudinal groove.

Nrf2 overexpression protects against paraquat-induced A549 cell injury primarily by upregulating P-glycoprotein and reducing intracellular paraquat accumulation.

Paraquat (PQ) intoxication causes thousands of mortalities every year, worldwide. Its pulmonary-targeted accumulation and the acute lung injury it subsequently causes, remain a challenge for detoxification treatment. A previous study has demonstrated that the upregulation of nuclear factor erythroid-2 related factor 2 (Nrf2) prevents PQ toxicity in cell line and murine models. As Nrf2 target genes include a group of membrane transporters, the current study assessed the protective mechanism exerted by Nrf2 against PQ toxicity and intracellular PQ accumulation via its effects on P-glycoprotein (P-gp), a downstream transporter of Nrf2. Adenovirus vectors containing the Nrf2 gene were transfected into A549 cells. Cell proliferation was assessed by Cell Counting Kit-8. The levels of LDH, MDA, SOD, TNF-α, IL-6 levels were detected using their respective ELISA kits. In addition, the levels of Nrf2 and P-gp protein expression were detected by western blot analysis. The concentration of PQ was measured by HPLC. The results revealed that overexpressed Nrf2 significantly increased P-gp protein levels, decreased the intracellular accumulation of PQ and attenuated PQ-induced toxicity. However, the protective effects of Nrf2 overexpression on PQ-challenged A549 cells were abrogated following cyclosporine A treatment, a competitive inhibitor of P-gp, which also increased intracellular PQ levels. These data indicated that Nrf2 gene overexpression prevented PQ toxicity in A549 cells, potentially via the upregulation of P-gp activity and the inhibition of intracellular PQ accumulation. Thus, Nrf2 and P-gp may serve as potential therapeutic targets for the treatment of PQ-induced injury.

[Effects of long-term fertilization on nitrogen fertilizer use efficiency in loessial soil region on the Loess Plateau, Northwest China]. / 长期施肥对黄土高原黄绵土氮肥利用率的影响.

Nitrogen fertilizer use efficiency is a key parameter to determine recommended nitrogen fertilizer amount and evaluate the effects of nitrogen fertilizer application. The effects of long-term fertilization on annual and accumulated nitrogen fertilizer use efficiency and the relationship between them were studied using a 34-year fertilization experiment (1981-2015) in loessial soil region. The results showed that fertilization had significant influence on annual and accumulated nitrogen ferti-lizer use efficiency of wheat, rape and flax in the period of 1983-2015. The highest mean annual nitrogen fertilizer use efficiency of wheat was achieved in N, P and K combination (NPK), thesecond was N combined with P (NP), 77.7% and 62.0% higher than N application alone respectively. The highest mean annual nitrogen fertilizer use efficiency of rape was achieved in NPK, the second was manure (M), N, P and K combination (MNPK), 93.7% and 65.6% higher than N application alone respectively. The annual nitrogenfertilizer use efficiency of M combined with N (MN) increased significantly compared with N application alone. The annual nitrogen fertilizer use efficiency of M, N and P combination (MNP) decreased significantly compared with NP. The annual nitrogen fertilizer use efficiency of MNPK decreased significantly compared with NPK.There was significant positive linear relationship between annual nitrogen fertilizer use efficiency and crop yield. The correlation between accumulated nitrogen fertilizer use efficiency and crop yield was not significant. It indicated that the annual nitrogen fertilizer use efficiency could be more effective in representing fertilizer use efficiency characteristics under given soil fertility levels, crop varieties and environmental conditions compared with accumulated nitrogen fertilizer use efficiency.