Abstract
We report the first evidence for high-mass star formation triggered by collisions of molecular clouds in M 33. Using the Atacama Large Millimeter/submillimeter Array, we spatially resolved ...filamentary structures of giant molecular cloud 37 in M 33 using 12CO(J = 2–1), 13CO(J = 2–1), and C18O(J = 2–1) line emission at a spatial resolution of ∼2 pc. There are two individual molecular clouds with a systematic velocity difference of ∼6 km s−1. Three continuum sources representing up to ∼10 high-mass stars with spectral types of B0V–O7.5V are embedded within the densest parts of molecular clouds bright in the C18O(J = 2–1) line emission. The two molecular clouds show a complementary spatial distribution with a spatial displacement of ∼6.2 pc, and show a V-shaped structure in the position–velocity diagram. These observational features traced by CO and its isotopes are consistent with those in high-mass star-forming regions created by cloud–cloud collisions in the Galactic and Magellanic Cloud H ii regions. Our new finding in M 33 indicates that cloud–cloud collision is a promising process for triggering high-mass star formation in the Local Group.
We present 12 mm Mopra observations of the dense (>103 cm−3) molecular gas towards the north-east of the W28 supernova remnant (SNR). This cloud is spatially well matched to the TeV gamma-ray source ...HESS J1801−233 and is known to be an SNR-molecular cloud interaction region. Shock-disruption is evident from broad NH3 (1,1) spectral linewidths in regions towards the W28 SNR, while strong detections of spatially extended NH3 (3,3), NH3(4,4) and NH3(6,6) inversion emission towards the cloud strengthen the case for the existence of high temperatures within the cloud. Velocity dispersion measurements and NH3(n,n)/(1,1) ratio maps, where n = 2, 3, 4 and 6, indicate that the source of disruption is from the side of the cloud nearest to the W28 SNR, suggesting that it is the source of cloud-disruption. Towards part of the cloud, the ratio of ortho to para-NH3 is observed to exceed 2, suggesting gas-phase NH3 enrichment due to NH3 liberation from dust-grain mantles. The measured NH3 abundance with respect to H2 is ∼(1.2 ± 0.5) × 10−9, which is not high, as might be expected for a hot, dense molecular cloud enriched by sublimated grain-surface molecules. The results are suggestive of NH3 sublimation and destruction in this molecular cloud, which is likely to be interacting with the W28 SNR shock.
Indonesia is a global hotspot of plant diversity. The country contains medicinal plants that have immense value to the people and worldwide. However, climate change is affecting the distribution of ...medicinal plants in Indonesia. In this study, the future greenhouse gas emission scenarios of RCP4.5 and RCP8.5 for a mid-term future projection to 2050 and a long-term future projection to 2080 were used to simulate the effect of climate change upon medicinal plants distribution within Indonesia. In 2050 and 2080, under both RCP scenarios species richness is expected to decrease over more than half the current distribution area of medicinal plant species. Over half of the medicinal plant species populations will lose up to 80% of their distribution area. Medicinal plant species on the islands of Papua, Java, and Sulawesi are predicted to have the largest reduction in distribution area. In addition, two-thirds of species will lose rather than gain areas of suitable climate under the future climate scenarios. Twenty medicinal plant species are identified as potentially being the most threatened by climate change in the future and are therefore the highest priority for conservation actions within Indonesia. Using these results, we recommend areas and species suitable for long term in situ and ex situ conservation within Indonesia.
Introduction
Effective monitoring of the
in situ
conservation status and change dynamics of landrace populations in their centers of origin ideally requires the identification of sites that are ...complementary in terms of the richness, uniqueness and coverage of genetic diversity.
Methods
We applied a 4-step approach to identify sites of high potato landrace diversity which will guide the set-up of a network of complementary prospective conservation observatories in Peru, the potato center of origin. A GIS mapping approach was used to determine which combination of sites would provide the most comprehensive and complementary genepool coverage. A landrace inventory was developed from 49 sources, comprising 47,272 landrace records, 97.1% with coordinates, which was used to derive landrace, cultivated species, and cultivar group richness. Data on known indicators of agrobiodiversity, including potato wild relative concurrence, cultivated area, ecogeographic diversity, and ethnolinguistic diversity were included in the spatial overlay analysis, which was used in conjunction with expert opinion data to provide further insight to hotspot selection.
Results
Thirteen hotspots with high, unique, and complementary levels of landrace diversity were identified. We recommend that robust baselines are established, documenting current diversity in these sites using semi-standardized methods and metrics for future tracking.
Discussion
Our results, while being the most robust of their kind to date, were inevitably affected by data gaps, infrastructure and hotspot biases. New documentation efforts should record landrace diversity in uncovered regions, as well as explore complementary mechanisms to track the conservation status of unique endemic landraces that occur in coldspots.
Crop wild relatives have a long history of use in potato breeding, particularly for pest and disease resistance, and are expected to be increasingly used in the search for tolerance to biotic and ...abiotic stresses. Their current and future use in crop improvement depends on their availability in ex situ germplasm collections. As these plants are impacted in the wild by habitat destruction and climate change, actions to ensure their conservation ex situ become ever more urgent. We analyzed the state of ex situ conservation of 73 of the closest wild relatives of potato (Solanum section Petota) with the aim of establishing priorities for further collecting to fill important gaps in germplasm collections. A total of 32 species (43.8%), were assigned high priority for further collecting due to severe gaps in their ex situ collections. Such gaps are most pronounced in the geographic center of diversity of the wild relatives in Peru. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, with only three species determined to be sufficiently represented currently. Priorities for further collecting include: (i) species completely lacking representation in germplasm collections; (ii) other high priority taxa, with geographic emphasis on the center of species diversity; (iii) medium priority species. Such collecting efforts combined with further emphasis on improving ex situ conservation technologies and methods, performing genotypic and phenotypic characterization of wild relative diversity, monitoring wild populations in situ, and making conserved wild relatives and their associated data accessible to the global research community, represent key steps in ensuring the long-term availability of the wild genetic resources of this important crop.
Over the past decade, plant DNA barcoding has emerged as a scientific breakthrough and is often used to help with species identification or as a taxonomical tool. DNA barcoding is very important in ...medicinal plant use, not only for identification purposes but also for the authentication of medicinal products. Here, a total of 61 Indonesian medicinal plant species from 30 families and a pair of ITS2,
,
, and
primers were used for a DNA barcoding study consisting of molecular and sequence analyses. This study aimed to analyze how the four identified DNA barcoding regions (ITS2,
,
, and
) aid identification and conservation and to investigate their effectiveness for DNA barcoding for the studied species. This study resulted in 212 DNA barcoding sequences and identified new ones for the studied medicinal plant species. Though there is no ideal or perfect region for DNA barcoding of the target species, we recommend
as the main region for Indonesian medicinal plant identification, with ITS2 and
as alternative or complementary regions. These findings will be useful for forensic studies that support the conservation of medicinal plants and their national and global use.
Crop wild relatives (CWR) are important sources of adaptive diversity for plant breeding programmes. This paper aims to investigate the extent to which the centres of crop origin/diversity are ...congruent with areas of high CWR diversity. We established the predicted potential CWR distributions for 1,425 CWR species related to 167 crops using 334,527 known distribution locations and generated a global CWR hotspot map. This was then compared to the centres of origin/diversity proposed by Vavilov (amended by Hawkes); Zeven and Zhukovsky’s mega gene centres, Harlan’s centres and non-centres of crop domestication; and crop domestication areas identified using current archaeological evidence proposed by Purugganan and Fuller. Greatest congruence between the global CWR hotspots and other concepts was found with the concept proposed by Vavilov and amended by Hawkes, but there remained significant differences between the CWR hotspots and Vavilov’s concept. This paper concludes that all four centre concepts reviewed have some overlap with CWR diversity but that Vavilov’s original concept has the closest geographic coincidence with CWR hotspots. With the benefit of significant additional global datasets to those used by Vavilov, we were able to suggest amendments to his concept, adding further centres based on CWR hotspots in west and east USA, West Africa, South-east Brazil and Australia. As a result of this study more precise targeting of CWR and crop landrace can be implemented in future, aiding global food and nutritional security.
Ensuring global food security in the face of climate change is critical to human survival. With a predicted human population of 9.6 billion in 2050 and the demand for food supplies expected to ...increase by 60% globally, but with a parallel potential reduction in crop production for wheat by 6.0%, rice by 3.2%, maize by 7.4%, and soybean by 3.1% by the end of the century, maintaining future food security will be a challenge. One potential solution is new climate-smart varieties created using the breadth of diversity inherent in crop wild relatives (CWRs). Yet CWRs are threatened, with 16-35% regarded as threatened and a significantly higher percentage suffering genetic erosion. Additionally, they are under-conserved, 95% requiring additional ex situ collections and less than 1% being actively conserved in situ; they also often grow naturally in disturbed habitats limiting standard conservation measures. The urgent requirement for active CWR conservation is widely recognized in the global policy context (Convention on Biological Diversity post-2020 Global Biodiversity Framework, UN Sustainable Development Goals, the FAO Second Global Plan of Action for PGRFA, and the FAO Framework for Action on Biodiversity for Food and Agriculture) and breeders highlight that the lack of CWR diversity is unnecessarily limiting crop improvement. CWRs are not spread evenly across the globe; they are focused in hotspots and the hottest region for CWR diversity is in West Asia and North Africa (WANA). The region has about 40% of global priority taxa and the top 17 countries with maximum numbers of CWR taxa per unit area are all in WANA. Therefore, improved CWR active conservation in WANA is not only a regional but a critical global priority. To assist in the achievement of this goal, we will review the following topics for CWRs in the WANA region: (1) conservation status, (2) community-based conservation, (3) threat status, (4) diversity use, (5) CURE-CWR hub: (ICARDA Centre of Excellence), and (6) recommendations for research priorities. The implementation of the recommendations is likely to significantly improve CWRs in situ and ex situ conservation and will potentially at least double the availability of the full breadth of CWR diversity found in WANA to breeders, and so enhance regional and global food and nutritional security.
Abstract
We report on a study of the high-mass star formation in the H ii region W 28 A2 by investigating the molecular clouds that extend over ∼5–10 pc from the exciting stars using the 12CO and ...13CO (J = 1–0) and 12CO (J = 2–1) data taken by NANTEN2 and Mopra observations. These molecular clouds consist of three velocity components with CO intensity peaks at VLSR ∼ −4 km s−1, 9 km s−1, and 16 km s−1. The highest CO intensity is detected at VLSR ∼ 9 km s−1, where the high-mass stars with spectral types O6.5–B0.5 are embedded. We found bridging features connecting these clouds toward the directions of the exciting sources. Comparisons of the gas distributions with the radio continuum emission and 8 μm infrared emission show spatial coincidence/anti-coincidence, suggesting physical associations between the gas and the exciting sources. The 12CO J = 2–1 to 1–0 intensity ratio shows a high value (≳0.8) toward the exciting sources for the −4 km s−1 and +9 km s−1 clouds, possibly due to heating by the high-mass stars, whereas the intensity ratio at the CO intensity peak (VLSR ∼ 9 km s−1) decreases to ∼0.6, suggesting self absorption by the dense gas in the near side of the +9 km s−1 cloud. We found partly complementary gas distributions between the −4 km s−1 and +9 km s−1 clouds, and the −4 km s−1 and +16 km s−1 clouds. The exciting sources are located toward the overlapping region in the −4 km s−1 and +9 km s−1 clouds. Similar gas properties are found in the Galactic massive star clusters RCW 38 and NGC 6334, where an early stage of cloud collision to trigger the star formation is suggested. Based on these results, we discuss the possibility of the formation of high-mass stars in the W 28 A2 region being triggered by cloud–cloud collision.
Despite being an increasingly important source of genes for crop breeding aimed at improving food security and climate change adaptation, crop wild relatives (CWRs) are globally threatened. A root ...cause of CWR conservation challenges is a lack of institutions and payment mechanisms by which the beneficiaries of CWR conservation services (such as breeders) could compensate those who can supply them. Given that CWR conservation generates important public good values, for the significant proportion of CWRs found outside of protected areas, there is a strong justification for the design of incentive mechanisms to support landowners whose management practices positively contribute to CWR conservation. This paper contributes to facilitating an improved understanding of the costs of in situ CWR conservation incentive mechanisms, based on a case study application of payments for agrobiodiversity conservation services across 13 community groups in three districts in Malawi. Results demonstrate a high willingness to participate in conservation activities, with average conservation tender bids per community group being a modest MWK 20,000 (USD 25) p.a. and covering 22 species of CWRs across 17 related crops. As such, there appears to be significant potential for community engagement in CWR conservation activities that is complementary to that required in protected areas and can be achieved at modest cost where appropriate incentive mechanisms can be implemented.
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