From leaf elements to biomass across forest biomes in the Himalayas
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EXPERIMENTAL DESIGN, INCLUDING (A) THE LOCATION OF THE KANGCHENJUNGA LANDSCAPE IN THE EASTERN HIMALAYAS, NEPAL, (B) THE SITUATION OF FOREST PLOTS ALONG THE WHOLE ELEVATIONAL GRADIENT, AND (C) HYPOTHETICAL FRAMEWORK OF ELEMENT-BASED TRAIT DIVERSITY AND (D) DECLINING BIOMASS ALONG THE STUDY GRADIENT. THE FRAMEWORK SHOWS MASS-RATIO (FOCUSING ON COMMUNITY WEIGHTED MEAN, CWM, WHERE TRAIT VALUE OF DIFFERENT SPECIES WAS SYMBOLIZED AS ARROWS POINTING UPWARD) AND COMPLEMENTARITY EFFECTS (FOCUSING ON FUNCTIONAL DIVERGENCE, FD, WHERE E1 TO E5 INDICATE 5 ELEMENTS IN TREE LEAVES AND REPRESENT NICHE PARTITIONING IN THE TRAIT SPACE. THE ELEVATION GRADIENT IS CHARACTERIZED BY: LOW (ELEVATION < 1000 M), MID (ELEVATION 1000-3000 M), AND HIGH-ELEVATION SITES (ELEVATION > 3000 M).
view moreCREDIT: ©SCIENCE CHINA PRESS
The growth, development, and functioning of plants in various environments depend on multiple elements. However, our understanding of how the element concentrations in leaves that are associated with plant functioning and adaptation affect biomass in tree communities along elevation has been limited. A study led by Prof. Eryuan Liang (Institute of Tibetan Plateau Research, Chinese Academy of Sciences), and Dr. Nita Dyola (Institute of Tibetan Plateau Research, Chinese Academy of Sciences and Université du Québec à Chicoutimi), together with the co-authors, demonstrated the linkages of ten leaf element (carbon, nitrogen, phosphorus, potassium, calcium, magnesium, zinc, iron, copper and manganese) contents in 1,859 trees from 116 species in shaping biomass accumulation from tropical forests (80 m asl) to alpine treeline (4200 m asl) in the Kangchenjunga Landscape, located in the eastern Nepal Himalayas, which is one of the most diverse regions in the world.
The study, published in the Science China Earth Sciences, explored the mechanisms regulating forest biomass by assessing the relative change in the mass-ratio effect (i.e., indicating dominant trait affecting biomass) and complementarity effect (i.e., indicating partitioning of resources) based on multiple leaf elements. The study highlighted that elevation plays a crucial role in regulating trait diversity among plant species and their biomass accumulation in the Himalayas (see the figure below).
The study revealed that a combination of elements and elevation better explained the variation in biomass, accounting for 52.2% of the variance, compared to the individual elemental diversity, which accounted for 0.05% to 21% of the variance in biomass. The findings highlighted the significance of resource partitioning at low elevations and competition in the middle elevations, both of which were positively associated with forest biomass. Although high variation in leaf nutrients improves species’ adaptability to changing environments, it also poses challenges by reducing biomass accumulation in stressful sites at higher elevations.
This study provides a roadmap to comprehend and predict the effect of elevation-dependent environmental shifts, on the functional diversity of elemental traits that shape biomass accumulation across biomes. This knowledge presents a new approach to explore the range of chemical traits that modulate biomass and ecosystem functioning, which is crucial for conserving and managing biodiversity in mountain ecosystems.
See the article:
Dyola N, Liang E, Peñuelas J, Camarero JJ, Sigdel SR, Aryal S, Lin W, Liu X, Liu Y, Xu X, Rossi S. 2024. Linking leaf elemental traits to biomass across forest biomes in the Himalayas. Science China Earth Sciences, 67(5): 1518-1528. https://doi.org/10.1007/s11430-023-1271-4
JOURNAL
Science China Earth Sciences
Harnessing plant viruses for the delivery of genome editing reagents in diverse plant species
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DELIVERING GENOME EDITING REAGENTS IN PLANTS USING POSITIVE-STRAND RNA VIRUSES (A) OR NEGATIVE-STRAND RNA VIRUSES (B) FOR HERITABLE EDITS.
view moreCREDIT: BEIJING ZHONGKE JOURNAL PUBLISING CO. LTD.
Genome editing holds great promise for the molecular breeding of plants, yet its application is hindered by the shortage of simple and effective means of delivering genome editing reagents into plants. Conventional plant transformation-based methods for the delivery of genome editing reagents into plants often involve prolonged tissue culture, a labor-intensive and technically challenging process for many elite crop cultivars. This bottleneck prevents the genomes from many elite crop cultivars from being edited in a cost-effective manner. Besides, genome editing strategies based on homology-directed repair (HDR) are highly versatile, but often depend on a large amount of donor DNA delivered, which can be difficult to achieve with many conventional methods. Both RNA viruses and DNA viruses have been employed to overcome these technical challenges.
RNA viruses have been harnessed for the delivery of the core components involved in genome editing in plants. The limitation in the capacity of positive-strand RNA viruses (PSVs) is compensated by their ability to invade germline cells in planta and induce heritable edits. Accordingly, PSV-based delivery strategies have been mostly applied to introduce guide RNA molecules into plant hosts that express the matching Cas nuclease gene, which often exceeds the size limit that PSVs can accommodate. On the contrary, negative-strand RNA viruses (NSVs) can accommodate longer DNA fragments, such as one encoding the entire sequence-specific nuclease machinery, but rarely enters the germline cells. As a result, NSVs-based delivery strategies often entail a subsequent plant regeneration process if heritable edits are desired.
Precision edits achieved via HDR usually involves an artificially supplied donor DNA as the repair template, which needs to be delivered at a high copy number to be effective. Geminiviruses comprise a family of plant DNA viruses whose genomes can replicate to a very high copy number in plant cells. This feature makes them ideal vectors for the delivery of repair donors. Geminiviral replicons have been successful utilized to generate specific editing outcomes in wheat, tomatoes, and tobacco etc.
A general trade-off between cargo capacity and vector mobility exists for currently available viral vectors. PSVs are promising tools for tissue culture-free gene editing, but they rely on an existing Cas-expressing line due to the limited capacity of the viral vector. NSV-based vectors can accommodate the entire CRISPR/Cas machinery, and thus can be used for genome editing in a transgene-free context, but often rely on a subsequence tissue culture process to recover plants carrying heritable edits. Similarly, GVRs are modified into replicon vectors with no infectivity and minimal mobility to make room for extra nucleotide sequences. It is desirable to develop viral vector systems with not only the ability to perform cargo delivery into germline cells, in planta, but also sufficient capacity for the complete CRISPR/Cas components. Meanwhile, more compact sequence-specific nucleases are strong candidates to be delivered using virus-based systems. Besides, it is worth exploring new components to be fused with the delivered cargos to enhance the systemic movement of the genome editing reagents to achieve germline edits. Furthermore, broad-spectrum viral delivery systems are required for application in a broader range of crop species. Biosafety and risk assessment of the application viral vectors are also worth additional investigation to reduce unintended burden on humans and the ecosystem.
In summary, the use of viral vectors to deliver genome editing components offers potential solutions to many current technical bottlenecks involved in genome editing in plants. More efficient delivery methods capable of generating heritable edits in a simple manner may be established in the future through the exploitation of novel viral species and engineered existing viruses for improved performance.
See the article:
Exploiting viral vectors to deliver genome editing reagents in plants
https://link.springer.com/article/10.1007/s42994-024-00147-7
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aBIOTECH
ARTICLE TITLE
Exploiting viral vectors to deliver genome editing reagents in plants
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