Chromosome-level genome of putative autohexaploid Actinidia deliciosa provides insights into polyploidisation and evolution.

Actinidia ('Mihoutao' in Chinese) includes species with complex ploidy, among which diploid Actinidia chinensis and hexaploid Actinidia deliciosa are economically and nutritionally important fruit crops. Actinidia deliciosa has been proposed to be an autohexaploid (2n = 174) with diploid A. chinensis (2n = 58) as the putative parent. A CCS-based assembly anchored to a high-resolution linkage map provided a chromosome-resolved genome for hexaploid A. deliciosa yielded a 3.91-Gb assembly of 174 pseudochromosomes comprising 29 homologous groups with 6 members each, which contain 39 854 genes with an average of 4.57 alleles per gene. Here we provide evidence that much of the hexaploid genome matches diploid A. chinensis; 95.5% of homologous gene pairs exhibited >90% similarity. However, intragenome and intergenome comparisons of synteny indicate chromosomal changes. Our data, therefore, indicate that if A. deliciosa is an autoploid, chromosomal rearrangement occurred following autohexaploidy. A highly diversified pattern of gene expression and a history of rapid population expansion after polyploidisation likely facilitated the adaptation and niche differentiation of A. deliciosa in nature. The allele-defined hexaploid genome of A. deliciosa provides new genomic resources to accelerate crop improvement and to understand polyploid genome evolution.

Divergent rhizosphere and non-rhizosphere soil microbial structure and function in long-term warmed steppe due to altered root exudation.

While there is an extensive body of research on the influence of climate warming on total soil microbial communities, our understanding of how rhizosphere and non-rhizosphere soil microorganisms respond to warming remains limited. To address this knowledge gap, we investigated the impact of 4 years of soil warming on the diversity and composition of microbial communities in the rhizosphere and non-rhizosphere soil of a temperate steppe, focusing on changes in root exudation rates and exudate compositions. We used open top chambers to simulate warming conditions, resulting in an average soil temperature increase of 1.1°C over a span of 4 years. Our results showed that, in the non-rhizosphere soil, warming had no significant impact on dissolved organic carbon concentrations, compositions, or the abundance of soil microbial functional genes related to carbon and nitrogen cycling. Moreover, soil microbial diversity and community composition remained largely unaffected, although warming resulted in increased complexity of soil bacteria and fungi in the non-rhizosphere soil. In contrast, warming resulted in a substantial decrease in root exudate carbon (by 19%) and nitrogen (by 12%) concentrations and induced changes in root exudate compositions, primarily characterized by a reduction in the abundance in alcohols, coenzymes and vitamins, and phenylpropanoids and polyketides. These changes in root exudation rates and exudate compositions resulted in significant shifts in rhizosphere soil microbial diversity and community composition, ultimately leading to a reduction in the complexity of rhizosphere bacterial and fungal community networks. Altered root exudation and rhizosphere microbial community composition therefore decreased the expression of functional genes related to soil carbon and nitrogen cycling. Interestingly, we found that changes in soil carbon-related genes were primarily driven by the fungal communities and their responses to warming, both in the rhizosphere and non-rhizosphere soil. The study of soil microbial structure and function in rhizosphere and non-rhizosphere soil provides an ideal setting for understanding mechanisms for governing rhizosphere and non-rhizosphere soil carbon and nitrogen cycles. Our results highlight the distinctly varied responses of soil microorganisms in the rhizosphere and non-rhizosphere soil to climate warming. This suggests the need for models to address these processes individually, enabling more accurate predictions of the impacts of climate change on terrestrial carbon cycling.

Using eDNA to survey amphibians: Methods, applications, and challenges.

In recent years, environmental DNA (eDNA) has received attention from biologists due to its sensitivity, convenience, labor and material efficiency, and lack of damage to organisms. The extensive application of eDNA has opened avenues for the monitoring and biodiversity assessment of amphibians, which are frequently small and difficult to observe in the field, in areas such as biodiversity survey assessment and detection of specific, rare and threatened, or alien invasive species. However, the accuracy of eDNA can be influenced by factors such as ambient temperature, pH, and false positives or false negatives, which makes eDNA an adjunctive tool rather than a replacement for traditional surveys. This review provides a concise overview of the eDNA method and its workflow, summarizes the differences between applying eDNA for detecting amphibians and other organisms, reviews the research progress in eDNA technology for amphibian monitoring, identifies factors influencing detection efficiency, and discusses the challenges and prospects of eDNA. It aims to serve as a reference for future research on the application of eDNA in amphibian detection.

Biotic and abiotic factors interplay in structuring the dynamics of microbial co-occurrence patterns in tropical mountainsides.

Ecological interactions are important for maintaining biodiversity and ecosystem functions. Particularly in stream biofilms, little is known about the distributional patterns of different taxonomic groups and their potential interactions along elevational gradients. Here, we investigated the bacterial and fungal community structures of stream biofilms across elevational gradients on Mount Kilimanjaro, and explored patterns of their distribution, diversity, community structures, and taxa co-occurrence. We found that fungal and bacterial richness were more convergent at higher elevations, while their community structures became significantly more divergent. Inferred network complexity and stability significantly decreased with increasing elevation for fungi, while an opposite trend was observed for bacteria. Further quantitative analyses showed that network structures of bacteria and fungi were more divergent as elevation increased. This pattern was strongly associated with shifts in abiotic factors, such as mean annual temperatures, water PO43--P, and stream width. By constructing bipartite networks, we showed the fungal-bacterial network to be less redundant, more clustering, and unstable with increasing elevation. Abiotic factors (e.g., temperatures and stream width) and microbial community properties (i.e., structure and composition) significantly explained the dynamic changes in fungal-bacterial network properties. Taken together, this study provides evidence for the interplay of biotic and abiotic factors structuring potential microbial interactions in stream biofilms along a mountainside elevational gradient.

Soil potentials to resist continuous cropping obstacle: Three field cases.

Continuous cropping has become the most common system in intensive, modern agricultural production; however, obstacles often appear in continuous cropping patterns after a few years of use. There have been several studies about the impacts of continuous cropping on soil microbial, but few about differences between soil experiencing continuous cropping obstacles and those where such obstacles had been resisted. Here, after ten or twenty years of continuous tobacco cropping, we collected soil samples investigating discrepancies in soil property and bacterial community between soils experiencing continuous cropping obstacles and soils where the obstacles were resisted providing insight into preventing and controlling continuous cropping obstacles. Results showed that soil organic matter (SOM), available phosphorus (AP), total nitrogen (TN), nitrate-N (NO3--N), and bacterial diversity of samples where continuous cropping obstacles had been resisted were significantly higher than those where continuous cropping obstacles were present. Besides, SOM, AP, TN, and Ammonium-N (NH4+-N) considerably affected the bacterial community. Among all variables, NH4+-N explained the largest proportion of bacterial community variation. Molecular ecological networks were used to putatively identify keystone taxa, including Acidobacteria Gp1, Acidobacteria Gp2, Acidobacteria Gp16, and WPS-1_genera_incertae_sedis. Their relative abundance significantly changed between the two conditions. Overall, our results indicate that decreases in soil nutrient content and bacterial diversity, and significant changes in some keystone taxa abundances may be important factors leading to increased soil-borne diseases and reduced tobacco production potential or quality. Thus, during agricultural production, we could regulate the stability of the soil-crop-microbial ecological system via crop rotation, intercropping, or the use of specialized bio-fertilizers and soil conditioners to mitigate continuous cropping obstacles.

Biotic and abiotic properties mediating sediment microbial diversity and function in a river-lake continuum.

A river-lake system plays an important role in water management by providing long-term and frequent water diversions. However, hydrological connectivity in the system can have a profound effect on sediment microbial communities through pH, nutrient concentrations, and benthos invertebrates. Consequently, identifying the key environmental factors and their driving mechanisms is vital for microbial adaptation strategies to extreme environments. In this study, we analyzed the significant difference in sediment bacterial and fungal community structures and diversity indices among Dongting Lake and its tributary rivers, which worked as a typical river-connected lake ecosystem. There were significant differences in biotic and abiotic environments in the sediment habitats of Dongting Lake and its tributary rivers. Random forest analysis revealed that pH and Mollusca were found to be the most important abiotic and biotic variables for predicting both bacterial and fungal community structures, respectively. The beta diversity decomposition analyses showed that the bacterial and fungal community compositional dissimilarities among different sections were dominated by species replacement processes, with more than half of the OTUs in each section being unique. Notably, both biotic and abiotic factors affected the number and the relative abundance of these bacterial and fungal unique OTUs, leading to changes in community composition. Mollusca, pH, TP, NO3-N, and NH4-N were negatively related to the relative abundance of Actinobacteria, Acidobacteria, Gemmatimonadetes, Planctomycetes, and Ascomycota, while Annelida and ORP were positively related to the relative abundance of Actinobacteria and Gemmatimonadetes. Additionally, PICRUSt analysis revealed that the functional dissimilarity among lakes and rivers was strengthened in unique species compared to all species in bacterial and fungal communities, and the changes of functional types helped to improve the habitat environment in the main Dongting Lake and promote the process of microbial growth. From our results, the role of macrozoobenthos and physicochemical characteristics in driving the sediment microbial community spatial variations became clear, which contributed to further understanding of the river-lake ecosystem.

[Spatial and Temporal Characteristics of Fractional Vegetation Cover and Its Response to Urbanization in Beijing].

Exploration of the spatiotemporal changes in fractional vegetation cover （FVC） and its response characteristics to urbanization is of great significance for urban ecological protection and planning in Beijing. This study analyzed the spatiotemporal characteristics of vegetation cover changes in Beijing from 2000 to 2020 using the Theil-Sen Median and Mann-Kendall methods based on a long-term time series vegetation cover dataset. Then, this study used the urbanization index as a key indicator of spatial urbanization and utilized the transect line and global grid analysis methods to investigate the response characteristics of FVC to different urbanization gradients. The results indicated that： ① FVC changes showed spatial and temporal heterogeneity. From 2000 to 2020, Beijing was predominantly covered by high vegetation, accounting for 65.22% of the total area, which was mainly distributed in ecological conservation areas consistent with the Jundu, Xishan, and Yaji Mountain ranges. The FVC presented an overall positive development trend, with a decreasing trend of areas with low FVC. The increase in FVC was significant （by 28.68%）, mainly distributed in ecological conservation areas and within a range of 10-12 km in concentric circles centered around Tiananmen Square. The urbanization index and FVC change rate were relatively high in Haidian District, Chaoyang District, Fengtai District, Shijingshan District, and Changping District. ② The artificial land surface in 2000, 2010, and 2020 was 9.69%, 13.64%, and 21.19%, respectively, with significant spatial agglomeration and strong spatial heterogeneity. During the urbanization process in Beijing, the increase in artificial land surface reached 11.5%, with the conversion from arable land to artificial land surface accounting for 53.83% of the total land use conversion area. ③ There was a significant negative correlation between FVC and the urbanization index, indicating that urbanization had a negative impact on regional FVC. However, as the urbanization process stabilized, this negative correlation tended to gradually weaken. Although the central urban areas were mainly characterized by low FVC, there was a significant increasing trend in the FVC, indicating a positive development in the FVC and an improvement in regional ecological quality, which was closely related to the governance of the mountain-water-forest-field-lake-grass-sand system. The results of the study can provide a basis for the development of vegetation restoration programs and ecological management measures in Beijing.

Different Adaption Strategies of Abundant and Rare Microbial Communities in Sediment and Water of East Dongting Lake.

The dynamics of aquatic microbes is of great importance for comprehending the acclimatisation and evolution of microorganisms in lake ecology. However, little is known about the adaption strategies of microbial communities in East Dongting Lake, which had special and complexity geographical characteristics. A semi-enclosed lake area (A) and a waterway connected to Yangtze River (B) both existed in the lake zone. Here, we investigated bacterial and fungal community diversity, community network and community assembly processes in sediment and water. The results indicated that the proportion of OTU numbers and their relative abundance for rare and abundant taxa were different obviously between sediment and water, but not between bacteria and fungi. However, abundant subcommunities dominated the shifts of bacterial community diversity and structure in A region, while rare subcommunities for fungal community diversity. Compared to fungal community, bacterial network was more compact and more key stones were identified as rare taxa. In addition, stochastic processes (dispersal limitation) drove the community assembly of abundant and rare subcommunities, but the effects of deterministic processes (including variable and heterogeneous selections) affected more on rare rather than abundant taxa. Partial Mantel test further indicated that the effect of environmental factors was a stronger force in shaping abundant bacterial subcommunities (TOC, NH4+-N, TN, and ORP) and rare fungal subcommunities (ORP). Environmental factors explained more of the variation in bacterial community structure than that in fungal community structure, although they had additional effects on fungal community diversity and community assembly. Moreover, bacterial community affected the fungal community as a biotic factor in water. This research provided new insights into better understanding of microbial communities in the complex environment of the East Dongting Lake.

Laboratory assessment of the impacts of transgenic Bt rice on the ecological fitness of the soil non-target arthropod, Folsomia candida (Collembola: Isotomidae).

Transgenic rice expressing Bacillus thuringiensis (Bt) endotoxins (Bt rice) for pest control is considered an important solution to food security in China. However, tests for potential effects on non-target soil organisms are required for environmental risk assessment. The soil collembolan Folsomia candida L. (Collembola: Isotomidae) is a potential non-target arthropod that is often used as a biological indicator in bio-safety assessments of transgenic crops. In the present study, the roots, stems, and leaves of Bt rice were exposed to F. candida under laboratory conditions, with survival, reproduction and growth of the collembolan as ecological fitness parameters. Significant differences in ecological fitness were found among the different treatments, including differences in the plant parts and varieties of non-Bt rice, presumably as the result of three factors: gene modification, plant parts and rice varieties. The fitness of F. candida was less affected by the different diets than by the exposure to the same materials mixed with soil. Our results clearly showed that there was no negative effect of different Bt rice varieties on the fitness of F. candida through either diet or soil exposure.

The Oriental spittlebug genus Paracercopis Schmidt (Hemiptera: Cercopoidea: Cercopidae) revisited, with description of one new species from Hubei, China.

The generic diagnostic characters of Paracercopis (Hemiptera: Cercopoidea: Cercopidae) are redefined and the autapomorphies are proposed to support the monophyly of the genus. Scanning electron micrographs of antennal sensilla and sensilla on rostral apex of P. seminigra (Melichar, 1902) are provided for the first time. A checklist together with new distribution records and key to the species of the genus are provided. Host plant associations of Paracercopis species are reported for the first time. Paracercopis unicolor Liang, Zhang & Xiao, sp. nov., representing the seventh and largest species of the genus is described from Hubei Province in south central China.

Comparison between optimized MaxEnt and random forest modeling in predicting potential distribution: A case study with Quasipaa boulengeri in China.

Random forest (RF) and MaxEnt models are shallow machine learning approaches that perform well in predicting species' potential distributions. RF models can produce robust results with the default automatic configuration in most cases, but it is necessary for MaxEnt to optimize the model settings to improve the performance, and the predictive performance difference between optimized MaxEnt and RF is uncertain. To explore this issue, the potential distribution of the endangered amphibian Quasipaa boulengeri in China was predicted using optimized MaxEnt and RF models. A total of 408 occurrence data were selected, 1000 locations were generated as pseudo-absence data by the geographic distance method, and 10,000 sites were selected as background data by creating a bias file. Partial ROC at different thresholds and success rate curves were used to compare the predictive performances between optimized MaxEnt and RF. Our results showed that the RF and optimized MaxEnt models both had good performance in predicting the potential distribution of Q. boulengeri, with the RF model performing slightly better whether based on partial ROC or success rate curves. Furthermore, the core suitable habitat regions of Q. boulengeri identified by RF and MaxEnt were similar and were all located in the Sichuan, Chongqing, Hubei, Hunan, and Guizhou provinces. However, the RF model produced a habitat suitability map with higher discrimination and greater heterogeneity. Temperature annual range, mean temperature of the driest quarter, and annual precipitation were the vital environmental variables limiting the distribution of Q. boulengeri. The RF model is the stronger machine learner. We believe it may be more applicable in predicting the native potential distributions of species with sufficient occurrence data, given the additional predictive detail, the simplicity of use, the computational time involved, and the operational complexity.

eDNA metabarcoding as a promising conservation tool to monitor fish diversity in Beijing water systems compared with ground cages.

Fish diversity, an important indicator of the health of aquatic ecosystems, is declining sharply due to water pollution, overfishing, climate change, and species invasion. For protecting fish diversity, effective surveying and monitoring are prerequisites. In this study, eDNA (environmental DNA) metabarcoding and ground cages were used to survey the fish diversity of the Chaobai and Beiyun Rivers in Beijing. Based on the two methods, we identified 40 species, belonging to 35 genera, 18 families, and six orders. The richness of fish identified by eDNA metabarcoding was significantly higher than that captured by ground cages in both rivers. The fish captured by the ground cage method were all recognized by eDNA metabarcoding, except Squalidus wolterstorffi and Saurogobio dabryi, which were captured only in ground cages. The correlation of relative abundance between the two methods was affected by the properties of the rivers, such as the flow rate. Fish caught by ground cage in the Beiyun River were identified by eDNA, but not in the Chaobai River. Our results also suggest that the Chaobai River has higher fish diversity than the Beiyun River and different community assemblage. In addition to differences in the natural properties of the focal rivers, the development of urbanization is also an important contributor to different community structures overserved. eDNA metabarcoding as a new survey tool has great application prospects, it provides certain theoretical data and methodological references for the protection and management of river fish diversity.

[Ecological Quality Assessment of the Wetlands in Beijing: Based on Plant Diversity].

Wetland plant diversity reveals key aspects of the environmental and ecological status of wetlands and plays an important role in the maintenance of ecosystem functions and services. The present study surveyed the plant species diversity of 22 wetlands in Beijing and, combining field data and remote sensing data, evaluated ecological qualities of the wetlands based on indicators of habitat status, plant species diversity, typical wetland plant community, and status of alien plant invasion. A total of 338 species (including varieties and subspecies) belonging to 220 genera of 74 families of wetland plants were recorded in Beijing. The wetlands could be divided into four types according to plant species composition, which showed a spatial gradient pattern from urban core to ecological conservation areas. Wetlands located in ecological conservation areas were of better ecological quality than those located in urban core and suburban plain areas. The value of ecological quality index (EQI) for Baihe River, Huaishahe-Huaijiuhe River, Jinniu Lake, Hanshiqiao Wetland, and Yongdinghe River (Mentougou Section) were in the top five, whereas the value of EQI for river-type wetlands located in suburban plain areas were relatively lower. The results of the canonical correspondence analysis indicated that the most critical factors affecting wetland plant species composition were the distance to the nearest road, water total nitrogen, and area percentage of ecological green land. Furthermore, the results of the canonical correlation analysis indicated that the most critical factors affecting wetland plant species diversity were the area percentage of construction land and water total organic carbon. Human activity intensity and water quality have a strong impact on the plant diversity and ecological quality of wetlands in Beijing. It is suggested that efforts should be made to strengthen the ecological protection and restoration of the river-type wetlands located in suburban plain areas.

[Establishment of an indicator system for comprehensive assessment on terrestrial biodiversity in China]. / ä¸­å›½é™†åŸŸç”Ÿç‰©å¤šæ ·æ€§ç»¼åˆè¯„ä¼°æŒ‡æ ‡ä½“ç³»æž„å»º.

The comprehensive evaluation of terrestrial biodiversity is a key basic work for biodiversity protection. Clarifying the status, trend, and driving factors of biodiversity is premise and necessary for formulating policies and measures of biodiversity protection. At present, there is no unified indicator system for the comprehensive assessment of terrestrial biodiversity in China. We constructed a comprehensive assessment indicator system of terrestrial biodiversity in China, by combining the Aichi biodiversity targets of the Convention on Biological Diversity and the sustainable development goals of the United Nations, learning from the development trend of biodiversity assessment in the world, and following the Pressure-State-Response framework. A total of 22 indicators were obtained, including eight status indicators, seven pressure indicators, and seven response indicators. The correlation and accessibility of the indicators were analyzed. These indicators could be applied to not only an independent assessment for biodiversity status, threatened and protection effectiveness, but also for the comprehensive assessment of terrestrial biodiversity to optimize and adjust priority protection areas and protection measures. Our results would provide a technical support for calculating green GDP and formulating regional ecological compensation policies.

A new species of Odorrana (Anura, Ranidae) from Hunan Province, China.

A new species, Odorrana sangzhiensis sp. nov., is described, based on five specimens from Sangzhi County, Zhangjiajie City, Hunan Province, China. Molecular phylogenetic analyses, based on mitochondrial 12S rRNA and 16S rRNA gene sequences, strongly support the new species as a monophyletic group nested into the O. schmackeri species complex. The new species can be distinguished from its congeners by a combination of the following characters: (1) body size medium (SVL: 42.1-45.1 mm in males, 83.3-92.7 mm in females); (2) dorsolateral folds absent; (3) tympanum diameter 1.53 times as long as the width of the disc of finger III in females; 2.3 times in males; (4) dorsal skin green with dense granules and sparse irregular brown spots; males with several large warts on dorsum; (5) two metacarpal tubercles; (6) relative finger lengths: I ≤ II < IV < III; (7) tibiotarsal articulation beyond the tip of the snout; (8) ventral surface smooth in females; throat and chest having pale spinules in adult males; (9) dorsal limbs green or yellow green with brown transverse bands; and (10) paired external vocal sacs located at corners of the throat, finger I with light yellow nuptial pad in males. This discovery increases the number of Odorrana species to 59 and those known from China to 37.

Fusing multidimensional hierarchical information into finer spatial landscape metrics.

One of the core issues of ecology is to understand the effects of landscape patterns on ecological processes. For this, we need to accurately capture changes in the fine landscape structures to avoid losing information about spatial heterogeneity. The landscape pattern indicators (LPIs) can characterize the spatial structures and give some information about landscape patterns. However, researches on LPIs had mainly focused on the horizontal structure of landscape patterns, while few studies addressed vertical relationships between the levels of hierarchical landscape structures. Thus, the ignorance of the vertical hierarchical relationships may cause serious biases and reduce LPIs' representational ability and accuracy. The hierarchy theory about the landscape pattern structures could notably reduce the loss of hierarchical information, and the information entropy could quantitatively describe the vertical status of landscape units. Therefore, we established a new multidimensional fusion method of LPIs based on hierarchy theory and information entropy. Here, we created a general fusion formula for commonly used simple LPIs based on two-grade land use data (whose land use classification system contains two grades/levels) and derived 3 fusion landscape pattern indicators (FLIs) with a case study. The results show that the information about fine spatial structure is captured by the fusion method. The regions with the most differences between the FLIs and the traditional LPIs are those with the largest vertical structure such as the ecological ecotones, where vertical structure was ignored before. The FLIs have a finer spatial representational ability and accuracy, not only retaining the main trend information of first-grade land use data, but also containing the internal detail information of second-grade land use data. Capturing finer spatial information of landscape patterns should encourage the application of fusion method, which should be suitable for more LPIs or more dimensional data. And the increased accuracy of FLIs will improve ecological models that rely on finer spatial information.

Responses of three successive generations of beet armyworm, Spodoptera exigua, fed exclusively on different levels of gossypol in cotton leaves.

The beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), is an important pest of numerous crops, and it causes economic damage in China. Use of secondary metabolic compounds in plants is an important method used to control this insect as a part of integrated pest management. In this study the growth, development, and food utilization of three successive generations of S. exigua fed on three cotton gossypol cultivars were examined. Significantly longer larval life-spans were observed in S. exigua fed on high gossypol cultivar M9101 compared with those fed on two low gossypol cultivars, ZMS13 and HZ401. The pupal weight of the first generation was significantly lower than that of the latter two generations fed on ZMS13 group. Significantly lower fecundity was observed in the second and third generations of S. exigua fed on M9101 compared with S. exigua fed on ZMS13 and HZ401. The efficiency of conversion was significantly higher in the first and third generations fed on HZ401 compared with those fed on ZMS13 and M9101. A significantly lower relative growth rate was observed in the three successive generations fed on M9101 compared with those fed on ZMS13 and HZ401. Cotton cultivars significantly affected the growth, development, and food utilization indices of S. exigua, except for frass and approximate digestibility. Development of S. exigua was significantly affected by relative consumption rate and efficiency of conversion of ingested food, but not by relative growth rate or approximate digestibility, suggesting that diet-utilization efficiency was different based on food quality and generation. Measuring the development and food utilization of S. exigua at the individual and population levels over more than one generation provided more meaningful predictions of long-term population dynamics.

A new species of Leptobrachella (Anura: Megophryidae) Smith, 1925 from Wuling Mountains in Hunan Province, China.

A new species of Leptobrachella, Leptobrachella wulingensis sp. nov. is described based on specimens collected from the Wuling mountains in Hunan Province, China. The new species can be distinguished from its congeners by a combination of having a SVL body size range of 24.5-32.8 mm in four adult males and 29.9-38.5 mm in three adult females; dorsal surface brown to reddish brown with indistinct markings; ventral surface creamy white, often with pale brown speckling on chest and margins; flanks with small to moderate black spots; skin on dorsum shagreened with sparse large warts, sometimes with short longitudinal ridges; toes with rudimentary webbing and narrow lateral fringes; dermal ridges under toes interrupted at the articulations; and iris bicolored with a bright orange or golden upper half, fading to silver in the lower half. Uncorrected sequence divergence between L. wulingensis sp. nov. and homologous 16S rRNA sequences available for all known species in the genus are ≥ 2.3%-2.9%.

Responses of phyllosphere microbiota and plant health to application of two different biocontrol agents.

The phyllosphere supports a tremendous diversity of microbes, which have the potential to influence plant biogeography and ecosystem function. Although biocontrol agents (BCAs) have been used extensively for controlling plant diseases, the ecological effects of BCAs on phyllosphere bacteria and the relationships between phyllosphere community and plant health are poorly understood. In this study, we explored the control efficiency of two BCA communities on bacterial wildfire disease by repeatedly spraying BCAs on tobacco leaves. The results of field tests showed that BCAs used in our study, especially BCA_B, had remarkable control effects against tobacco wildfire disease. The higher control efficiency of BCA_B might be attributed to a highly diverse and complex community in the phyllosphere. By 16S ribosomal RNA gene sequencing, we found that phyllosphere microbial community, including community diversity, taxonomic composition and microbial interactions, changed significantly by application of BCAs. According to the correlation analysis, it showed that wildfire disease infection of plants was negatively related to phyllosphere microbial diversity, indicating a highly diverse community in the phyllosphere might prevent pathogens invasion and colonization. In addition, we inferred that a more complex network in the phyllosphere might be beneficial for decreasing the chances of bacterial wildfire outbreak, and the genera of Pantoea and Sphingomonas might play important roles in wildfire disease suppression. These correlations between phyllosphere community and plant health will improve our understanding on the ecological function of phyllosphere community on plants.

Coexistence of Bacillus thuringiensis (Bt)-transgenic and conventional rice affects insect abundance and plant fitness in fields.

BACKGROUND: As genetically modified (GM) crops are cultivated worldwide, concerns are emerging about the ecological consequences of the coexistence of transgenic and non-transgenic crops in fields. We first conducted field experiments using insect-resistant transgenic rice expressing Bacillus thuringiensis (Bt-transgenic rice) and its counterpart conventional rice (Oryza sativa L.) with or without insecticide spraying in 2013 and 2014. In 2015 and 2016, Bt-transgenic and conventional rice plants were employed in pure and mixed cages, with an infestation of the target insect (Chilo suppressalis) and with insecticide spraying as the control treatment to prevent target insect infestation. RESULTS: The presence of Bt-transgenic rice decreased the abundance of target insects but did not affect non-target insects and predators in fields. Compared with conventional rice, Bt-transgenic rice showed more empty seeds but comparable seed production in cages. The infestation of target insects significantly decreased the plant fitness of conventional rice in pure cages, but did not affect its fitness when conventional rice coexisted with Bt-transgenic rice. In mixed cages, the presence of Bt-transgenic rice decreased the abundance of target insects and the percentage of dead sheaths in conventional rice. CONCLUSION: The presence of Bt-transgenic rice benefits the growth and reproduction of non-transgenic rice in fields because of a decreased abundance of target insects. © 2018 Society of Chemical Industry.