Pub Date : 2020-05-03DOI: 10.1080/07352689.2020.1782568
U. Subedi, J. Ozga, Guanqun Chen, N. Foroud, S. Singer
Abstract The demand for vegetable oils is increasing at a rapid pace due to our ever-expanding population, growing global affluence, changing dietary choices, and the need for renewable plant-derived resources. However, oilseed production is negatively impacted by unpredictable environmental conditions caused by climate change, as well as associated increases in disease and pest infestations. Unfortunately, while conventional breeding techniques have been used to provide gains in terms of oilseed yields, they are often imprecise and lengthy processes. Crops derived from transgenic approaches, on the other hand, have proven difficult to get to market due to negative public perception and onerous regulatory requirements. Genome editing, primarily using the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) platform, is a relatively recent addition to our plant breeding toolkit that allows the rapid generation of precise targeted genetic changes that can be indistinguishable from spontaneous mutations. In addition, the resulting plants can be made transgene-free with relative ease. While genome editing has been successfully used to modify a plethora of genes in the model plant Arabidopsis thaliana, the technology is only just taking off in oilseed crop species. This review discusses advances that have been made to-date using CRISPR/Cas-mediated genome editing of oilseed crops to improve plant productivity under favorable and sub-optimal environmental conditions, leading to increased seed yields or reduced losses. Furthermore, we also examine potential avenues for future enhancements in these traits using this molecular breeding tool.
{"title":"CRISPR/Cas-Mediated Genome Editing for the Improvement of Oilseed Crop Productivity","authors":"U. Subedi, J. Ozga, Guanqun Chen, N. Foroud, S. Singer","doi":"10.1080/07352689.2020.1782568","DOIUrl":"https://doi.org/10.1080/07352689.2020.1782568","url":null,"abstract":"Abstract The demand for vegetable oils is increasing at a rapid pace due to our ever-expanding population, growing global affluence, changing dietary choices, and the need for renewable plant-derived resources. However, oilseed production is negatively impacted by unpredictable environmental conditions caused by climate change, as well as associated increases in disease and pest infestations. Unfortunately, while conventional breeding techniques have been used to provide gains in terms of oilseed yields, they are often imprecise and lengthy processes. Crops derived from transgenic approaches, on the other hand, have proven difficult to get to market due to negative public perception and onerous regulatory requirements. Genome editing, primarily using the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas) platform, is a relatively recent addition to our plant breeding toolkit that allows the rapid generation of precise targeted genetic changes that can be indistinguishable from spontaneous mutations. In addition, the resulting plants can be made transgene-free with relative ease. While genome editing has been successfully used to modify a plethora of genes in the model plant Arabidopsis thaliana, the technology is only just taking off in oilseed crop species. This review discusses advances that have been made to-date using CRISPR/Cas-mediated genome editing of oilseed crops to improve plant productivity under favorable and sub-optimal environmental conditions, leading to increased seed yields or reduced losses. Furthermore, we also examine potential avenues for future enhancements in these traits using this molecular breeding tool.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1782568","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45415968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-03DOI: 10.1080/07352689.2020.1778924
S. Goel, Kalpana Singh, S. Grewal, M. Nath
Abstract Drought tolerance is a complex trait and being a yield limiting factor has become a significant threat to global food security. The complexity has limited the development of drought tolerant wheat cultivars by classical breeding. In recent years, molecular markers associated with genes for drought signaling pathways have been reported. Marker assisted selection (MAS) and genetic transformation of wheat with different genes/transcription factors have been used to improve drought tolerance. Notably, emergence of “Omics” techniques including transcriptomics and proteomics have helped to identify and characterize genes involved in drought tolerance. Together, all these efforts have helped us to improve our understanding of the complex drought tolerance mechanism(s). Here, we have reviewed the different approaches for improvement of drought tolerance in wheat including MAS, QTL mapping, transgenic development, genome editing, and the application of “Omics” technologies.
{"title":"Impact of “Omics” in Improving Drought Tolerance in Wheat","authors":"S. Goel, Kalpana Singh, S. Grewal, M. Nath","doi":"10.1080/07352689.2020.1778924","DOIUrl":"https://doi.org/10.1080/07352689.2020.1778924","url":null,"abstract":"Abstract Drought tolerance is a complex trait and being a yield limiting factor has become a significant threat to global food security. The complexity has limited the development of drought tolerant wheat cultivars by classical breeding. In recent years, molecular markers associated with genes for drought signaling pathways have been reported. Marker assisted selection (MAS) and genetic transformation of wheat with different genes/transcription factors have been used to improve drought tolerance. Notably, emergence of “Omics” techniques including transcriptomics and proteomics have helped to identify and characterize genes involved in drought tolerance. Together, all these efforts have helped us to improve our understanding of the complex drought tolerance mechanism(s). Here, we have reviewed the different approaches for improvement of drought tolerance in wheat including MAS, QTL mapping, transgenic development, genome editing, and the application of “Omics” technologies.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1778924","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42540074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-05-03DOI: 10.1080/07352689.2020.1782069
J. Somasundaram, N. Sinha, R. Dalal, R. Lal, M. Mohanty, A. Naorem, K. M. Hati, R. Chaudhary, A. Biswas, A. Patra, S. K. Chaudhari
Abstract Of late, intensive farming for higher food production is often associated with many negative implications for soil systems, such as decline of soil organic matter (SOM), increase in risks of soil erosion by wind and/or water, decline in soil biological diversity, increase in degradation of soil physical quality, lower nutrient-use efficiency, high risks of groundwater pollution, falling water tables, increasing salinization and waterlogging, in-field burning of crop residues, pollution of air and emission of greenhouse gases (GHG), leading to global warming, and decline in factor productivity. These negative implications necessitate an objective review of strategies to develop sustainable management practices, which could not only sustain soil health and ensure food security, but also enhance carbon sequestration, decrease GHG emissions, and offer clean and better ecosystem services. Conservation agriculture (CA), that includes reduced or no-till practices along with crop residue retention and mixed crop rotations, offers multiple benefits. Adoption of a system-based CA conserves water, improves and creates more efficient use of natural resources through the integrated management of available soil nutrients, water, and biological resources, and enhances use efficiency of external inputs. Due to apparent benefits of CA, it is increasingly being adopted and now covers about 180 million hectares (Mha) worldwide. However, in South Asia its spread is low (<5 Mha), mostly concentrated in the Indo-Gangetic Plains (IGP). In this region, one of the serious issues is “residue burning” with severe environmental impacts. A huge amount of crop residue left over after the combine harvest of rice has forced farmers to practice widespread residue burning (∼140 M tonnes) to cope with excessive stubble and also for timely planting/sowing of succeeding crops. In rice-wheat cropping systems, which cover more than 10 Mha in the IGP, CA practices are relatively more accepted by farmers. In these systems, any delay in sowing leads to yield penalty of 1–1.5% per day after the optimum sowing date of wheat. The strong adoption of CA practices in IGP is mainly to overcome delayed sowing due to the field preparation and control of weeds, timely planting, and also escape from terminal heat during the grain-filling stage. Major challenges to CA adoption in South Asia are small land holdings (<1 ha), low technological reach to farmers, nonavailability of suitable farm implements for small farm holders, and the staunch conventional farming mind-set. South Asia region consists of many countries of diverse agro-ecologies with contrasting farming systems and management. This region, recently known for rapid economic growth and increasing population, necessitates higher food production and also hot-spots for adoption of CA technologies. Therefore, in this review critically explores the possibility, extent of area, prospects, challenges, and benefits of CA in South Asia. HI
{"title":"No-Till Farming and Conservation Agriculture in South Asia – Issues, Challenges, Prospects and Benefits","authors":"J. Somasundaram, N. Sinha, R. Dalal, R. Lal, M. Mohanty, A. Naorem, K. M. Hati, R. Chaudhary, A. Biswas, A. Patra, S. K. Chaudhari","doi":"10.1080/07352689.2020.1782069","DOIUrl":"https://doi.org/10.1080/07352689.2020.1782069","url":null,"abstract":"Abstract Of late, intensive farming for higher food production is often associated with many negative implications for soil systems, such as decline of soil organic matter (SOM), increase in risks of soil erosion by wind and/or water, decline in soil biological diversity, increase in degradation of soil physical quality, lower nutrient-use efficiency, high risks of groundwater pollution, falling water tables, increasing salinization and waterlogging, in-field burning of crop residues, pollution of air and emission of greenhouse gases (GHG), leading to global warming, and decline in factor productivity. These negative implications necessitate an objective review of strategies to develop sustainable management practices, which could not only sustain soil health and ensure food security, but also enhance carbon sequestration, decrease GHG emissions, and offer clean and better ecosystem services. Conservation agriculture (CA), that includes reduced or no-till practices along with crop residue retention and mixed crop rotations, offers multiple benefits. Adoption of a system-based CA conserves water, improves and creates more efficient use of natural resources through the integrated management of available soil nutrients, water, and biological resources, and enhances use efficiency of external inputs. Due to apparent benefits of CA, it is increasingly being adopted and now covers about 180 million hectares (Mha) worldwide. However, in South Asia its spread is low (<5 Mha), mostly concentrated in the Indo-Gangetic Plains (IGP). In this region, one of the serious issues is “residue burning” with severe environmental impacts. A huge amount of crop residue left over after the combine harvest of rice has forced farmers to practice widespread residue burning (∼140 M tonnes) to cope with excessive stubble and also for timely planting/sowing of succeeding crops. In rice-wheat cropping systems, which cover more than 10 Mha in the IGP, CA practices are relatively more accepted by farmers. In these systems, any delay in sowing leads to yield penalty of 1–1.5% per day after the optimum sowing date of wheat. The strong adoption of CA practices in IGP is mainly to overcome delayed sowing due to the field preparation and control of weeds, timely planting, and also escape from terminal heat during the grain-filling stage. Major challenges to CA adoption in South Asia are small land holdings (<1 ha), low technological reach to farmers, nonavailability of suitable farm implements for small farm holders, and the staunch conventional farming mind-set. South Asia region consists of many countries of diverse agro-ecologies with contrasting farming systems and management. This region, recently known for rapid economic growth and increasing population, necessitates higher food production and also hot-spots for adoption of CA technologies. Therefore, in this review critically explores the possibility, extent of area, prospects, challenges, and benefits of CA in South Asia. HI","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1782069","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59480506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-03DOI: 10.1080/07352689.2020.1763541
Anusuya Willis, J. Woodhouse
Abstract Cyanobacteria were the first oxygenic photosynthersizers, evolving ∼3.5 bya, they have since radiated into one of the most diverse and widely distributed phyla of bacteria. Cyanobacterial diversification occurs through ecological adaptation, facilitated by asexual reproduction, homologous recombination and horizontal gene transfer, and selection pressures on ecotypes leading to speciation. Delimiting cyanobacterial species is, thus, fraught with difficulties and a clear taxonomy has not yet been universally accepted. This review discusses diversity and description of cyanobacteria: covering traditional and new methods to define species boundaries and concluding with a focus on the advances made through genomics. Examples from the genera Raphidiopsis, Microcystis, and Prochlorococcus are used throughout. Genome plasticity allows cyanobacteria to rapidly adapt and be resilient to environmental changes, illustrating the means of their persistence, and is an important aspect of their biology. Genomics has revealed generalist and specialist genome strategies, intraspecific diversity, and genome evolution in response to environmental stimuli. New taxonomic definitions will need to account for intraspecific genetic variation, with a species classification that is relevant to a species concept and scientific endeavors. Capturing intraspecific diversity with comparative genomics may provide a new path to species classification. This is demonstrated with two case studies; comparison of available genomes shows differing species delineation of Raphidiopsis and Microcystis. In both genera, species boundaries occur at ∼96% average nucleotide identity (ANI), where homologous recombination is constrained, but speciation of Raphidiopsis raciborskii, R. brookii, and R. curvata has occurred through geographic isolation, whereas available data on Microcystis contain at least 15 species, reflecting, to differing extents, different ecotypes, which may co-exist. Both case studies question the relative importance of species-specific versus habitat specific gene pools as drivers of inter- and intraspecific diversity.
蓝藻是最早的含氧光合作用菌，进化约3.5年，它们已经辐射到最多样化和广泛分布的细菌门之一。蓝藻的多样化是通过生态适应发生的，通过无性繁殖、同源重组和水平基因转移以及生态型的选择压力导致物种形成。划定蓝藻物种，因此，充满了困难和一个明确的分类尚未被普遍接受。这篇综述讨论了蓝藻的多样性和描述:涵盖了传统和新的方法来定义物种边界，并重点讨论了通过基因组学取得的进展。从Raphidiopsis属、微囊藻属和原绿球藻属的例子贯穿始终。基因组可塑性使蓝藻能够迅速适应和适应环境变化，这说明了它们的持久性，是它们生物学的一个重要方面。基因组学揭示了通才和专才基因组策略、种内多样性和基因组进化对环境刺激的响应。新的分类学定义将需要考虑种内遗传变异，与物种概念和科学努力相关的物种分类。利用比较基因组学捕获种内多样性可能为物种分类提供一条新的途径。通过两个案例研究证明了这一点;现有基因组的比较显示了Raphidiopsis和Microcystis的不同物种描述。在这两个属中，物种边界发生在约96%的平均核苷酸同源性(ANI)，同源重组受到限制，但Raphidiopsis raciborskii, R. brookii和R. curvata的物种形成是通过地理隔离发生的，而Microcystis的现有数据包含至少15种，在不同程度上反映了不同的生态型，这些生态型可能共存。这两个案例研究都质疑物种特异性与栖息地特异性基因库作为种间和种内多样性驱动因素的相对重要性。
{"title":"Defining Cyanobacterial Species: Diversity and Description Through Genomics","authors":"Anusuya Willis, J. Woodhouse","doi":"10.1080/07352689.2020.1763541","DOIUrl":"https://doi.org/10.1080/07352689.2020.1763541","url":null,"abstract":"Abstract Cyanobacteria were the first oxygenic photosynthersizers, evolving ∼3.5 bya, they have since radiated into one of the most diverse and widely distributed phyla of bacteria. Cyanobacterial diversification occurs through ecological adaptation, facilitated by asexual reproduction, homologous recombination and horizontal gene transfer, and selection pressures on ecotypes leading to speciation. Delimiting cyanobacterial species is, thus, fraught with difficulties and a clear taxonomy has not yet been universally accepted. This review discusses diversity and description of cyanobacteria: covering traditional and new methods to define species boundaries and concluding with a focus on the advances made through genomics. Examples from the genera Raphidiopsis, Microcystis, and Prochlorococcus are used throughout. Genome plasticity allows cyanobacteria to rapidly adapt and be resilient to environmental changes, illustrating the means of their persistence, and is an important aspect of their biology. Genomics has revealed generalist and specialist genome strategies, intraspecific diversity, and genome evolution in response to environmental stimuli. New taxonomic definitions will need to account for intraspecific genetic variation, with a species classification that is relevant to a species concept and scientific endeavors. Capturing intraspecific diversity with comparative genomics may provide a new path to species classification. This is demonstrated with two case studies; comparison of available genomes shows differing species delineation of Raphidiopsis and Microcystis. In both genera, species boundaries occur at ∼96% average nucleotide identity (ANI), where homologous recombination is constrained, but speciation of Raphidiopsis raciborskii, R. brookii, and R. curvata has occurred through geographic isolation, whereas available data on Microcystis contain at least 15 species, reflecting, to differing extents, different ecotypes, which may co-exist. Both case studies question the relative importance of species-specific versus habitat specific gene pools as drivers of inter- and intraspecific diversity.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1763541","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48518035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-03DOI: 10.1080/07352689.2020.1770942
Di Zhang, Moxian Chen, F. Zhu, Jianhua Zhang, Ying-Gao Liu
Abstract Serine/arginine-rich (SR) proteins are widely found in higher eukaryotes, including metazoans and plants. They form a major family of essential splicing factors that function in both constitutive splicing (CS) and alternative splicing (AS). Some SR proteins can also shuttle between the nucleus and cytoplasm and have roles beyond splicing. The activities of SR proteins are required for many living organisms to maintain normal growth and development. Although SR genes have been identified in numerous plants, they are less studied than those found in animals. The results of existing research suggest that plant SR proteins share many similar properties with their animal counterparts. However, plants generally have a higher number of SR proteins that display largely redundant functions under normal conditions but participate in specific stress responses. Moreover, many animal and plant SR genes are alternatively spliced and can be regulated by themselves or other SR proteins. These AS events, often coupled to nonsense-mediated decay (NMD), enable a mechanism for protein amount control under different conditions but sometimes also lead to translated protein isoforms with different functions. Here, we summarize the key findings of SR proteins in animals and plants and compare the essential characteristics of SR studies in these two research areas.
{"title":"Emerging Functions of Plant Serine/Arginine-Rich (SR) Proteins: Lessons from Animals","authors":"Di Zhang, Moxian Chen, F. Zhu, Jianhua Zhang, Ying-Gao Liu","doi":"10.1080/07352689.2020.1770942","DOIUrl":"https://doi.org/10.1080/07352689.2020.1770942","url":null,"abstract":"Abstract Serine/arginine-rich (SR) proteins are widely found in higher eukaryotes, including metazoans and plants. They form a major family of essential splicing factors that function in both constitutive splicing (CS) and alternative splicing (AS). Some SR proteins can also shuttle between the nucleus and cytoplasm and have roles beyond splicing. The activities of SR proteins are required for many living organisms to maintain normal growth and development. Although SR genes have been identified in numerous plants, they are less studied than those found in animals. The results of existing research suggest that plant SR proteins share many similar properties with their animal counterparts. However, plants generally have a higher number of SR proteins that display largely redundant functions under normal conditions but participate in specific stress responses. Moreover, many animal and plant SR genes are alternatively spliced and can be regulated by themselves or other SR proteins. These AS events, often coupled to nonsense-mediated decay (NMD), enable a mechanism for protein amount control under different conditions but sometimes also lead to translated protein isoforms with different functions. Here, we summarize the key findings of SR proteins in animals and plants and compare the essential characteristics of SR studies in these two research areas.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1770942","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47394219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-03DOI: 10.1080/07352689.2020.1768465
B. Lamont, J. Pausas, Tianhua He, E. Witkowski, M. Hanley
Abstract Serotiny is the prolonged storage of seeds in closed cones or fruits held within the crown of woody plants. It is widespread throughout fireprone vegetation with a predominantly winter rainfall, especially in Mediterrnanean-type ecosystems (MTEs). Nonstorage is a feature of fireprone vegetation with summer-dominant rainfall or nonfireprone vegetation. Serotiny confers fitness benefits on an individual when fire return intervals fall between age to reproductive maturity and the plant life span. The level of serotiny within and between species varies greatly along a continuum indicating highly plastic responses to different environmental conditions. Here we review how and why the traits that underpin this reproductive syndrome evolved and continue to control the occurrence of species in contemporary landscapes. We documented 1345 serotinous species in fireprone regions of Australia, South Africa, the Mediterranean Basin, North America, and Asia. The length of seed storage varies from a few years (weak serotiny) to >10 years (strong serotiny), with remarkable diversity even within clades. We show how the interplay between postfire and interfire seedling recruitment dictates the expression of serotiny along a strong serotiny/nonserotiny continuum, and that, where strong serotiny is favored, the ‘gene support for serotiny’ builds up over successive generations. Nonserotiny is favored in the absence of fire or occurs at intervals exceeding plant longevity, but also when the fire is so frequent that only resprouters can survive. We identify 23 traits associated with serotiny/nonserotiny syndromes that are subject to both environmental and phylogenetic constraints. While all are coordinated for maximum fitness, some traits, such as protection from granivores, are only indirectly related to the fire regime. Serotiny has a long history extending back to the Triassic. The rate of serotinous-lineage proliferation has fluctuated greatly over time but peaked over the last 5 million years. Nonserotinous species have evolved from serotinous ancestors in response to increased fire frequency, or as plants migrated to fire-free habitats. We note that contemporary shifts in climate, land-use, and exploitation have had a profound, but disproportionate, effect on the conservation status and evolutionary trajectory of serotinous species in MTEs. Escalating anthropogenic impacts increase the need to understand how and why serotiny is such a prominent feature of some fireprone ecosystems. We highlight avenues for future research and argue for the use of temporally based measures of serotiny to facilitate comparisons between studies.
{"title":"Fire as a Selective Agent for both Serotiny and Nonserotiny Over Space and Time","authors":"B. Lamont, J. Pausas, Tianhua He, E. Witkowski, M. Hanley","doi":"10.1080/07352689.2020.1768465","DOIUrl":"https://doi.org/10.1080/07352689.2020.1768465","url":null,"abstract":"Abstract Serotiny is the prolonged storage of seeds in closed cones or fruits held within the crown of woody plants. It is widespread throughout fireprone vegetation with a predominantly winter rainfall, especially in Mediterrnanean-type ecosystems (MTEs). Nonstorage is a feature of fireprone vegetation with summer-dominant rainfall or nonfireprone vegetation. Serotiny confers fitness benefits on an individual when fire return intervals fall between age to reproductive maturity and the plant life span. The level of serotiny within and between species varies greatly along a continuum indicating highly plastic responses to different environmental conditions. Here we review how and why the traits that underpin this reproductive syndrome evolved and continue to control the occurrence of species in contemporary landscapes. We documented 1345 serotinous species in fireprone regions of Australia, South Africa, the Mediterranean Basin, North America, and Asia. The length of seed storage varies from a few years (weak serotiny) to >10 years (strong serotiny), with remarkable diversity even within clades. We show how the interplay between postfire and interfire seedling recruitment dictates the expression of serotiny along a strong serotiny/nonserotiny continuum, and that, where strong serotiny is favored, the ‘gene support for serotiny’ builds up over successive generations. Nonserotiny is favored in the absence of fire or occurs at intervals exceeding plant longevity, but also when the fire is so frequent that only resprouters can survive. We identify 23 traits associated with serotiny/nonserotiny syndromes that are subject to both environmental and phylogenetic constraints. While all are coordinated for maximum fitness, some traits, such as protection from granivores, are only indirectly related to the fire regime. Serotiny has a long history extending back to the Triassic. The rate of serotinous-lineage proliferation has fluctuated greatly over time but peaked over the last 5 million years. Nonserotinous species have evolved from serotinous ancestors in response to increased fire frequency, or as plants migrated to fire-free habitats. We note that contemporary shifts in climate, land-use, and exploitation have had a profound, but disproportionate, effect on the conservation status and evolutionary trajectory of serotinous species in MTEs. Escalating anthropogenic impacts increase the need to understand how and why serotiny is such a prominent feature of some fireprone ecosystems. We highlight avenues for future research and argue for the use of temporally based measures of serotiny to facilitate comparisons between studies.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1768465","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44501483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-03DOI: 10.1080/07352689.2020.1768350
Yuting Luan, Xiumin Fu, Pengjun Lu, D. Grierson, Changjie Xu
Abstract Carotenoids are one of the most abundant natural pigments on earth. They accumulate in plastids and play many important roles in biological processes in plants. The structure and quantity of carotenoids vary extensively in different plant species and varieties and over the past three decades the molecular mechanisms underlying these differences have been elucidated. Multiple mechanisms have been discovered, including evolution of novel carotenogenic enzymes and novel catalytic functions, alteration in carotenogenic enzyme activity caused by gene body sequence mutations, changes in gene expression resulting from promoter mutations, difference in expression of noncarotenogenic genes involved in regulation of carotenoid sequestration, plastid sink capacity or transcriptional and epigenetic regulation, as well as effects of related metabolic events. These mechanisms are summarized here, with the aim of providing guidance for future studies on this topic and for genetic manipulation of carotenoid accumulation in plants.
{"title":"Molecular Mechanisms Determining the Differential Accumulation of Carotenoids in Plant Species and Varieties","authors":"Yuting Luan, Xiumin Fu, Pengjun Lu, D. Grierson, Changjie Xu","doi":"10.1080/07352689.2020.1768350","DOIUrl":"https://doi.org/10.1080/07352689.2020.1768350","url":null,"abstract":"Abstract Carotenoids are one of the most abundant natural pigments on earth. They accumulate in plastids and play many important roles in biological processes in plants. The structure and quantity of carotenoids vary extensively in different plant species and varieties and over the past three decades the molecular mechanisms underlying these differences have been elucidated. Multiple mechanisms have been discovered, including evolution of novel carotenogenic enzymes and novel catalytic functions, alteration in carotenogenic enzyme activity caused by gene body sequence mutations, changes in gene expression resulting from promoter mutations, difference in expression of noncarotenogenic genes involved in regulation of carotenoid sequestration, plastid sink capacity or transcriptional and epigenetic regulation, as well as effects of related metabolic events. These mechanisms are summarized here, with the aim of providing guidance for future studies on this topic and for genetic manipulation of carotenoid accumulation in plants.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1768350","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47356702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/07352689.2020.1741923
Wen-qiu Wang, A. Allan, Xue‐ren Yin
Abstract The role of protein-encoding genes in determining phenotype is well established, whereas the impact of small RNAs in regulating horticultural traits is being gradually recognized. Small RNAs are small noncoding RNAs of 20–24-nt, which regulate target genes by post-transcriptional regulation or de-novo DNA methylation. In plants, small RNAs are classified into the following two major categories, microRNA (miRNA) and short interfering RNA (siRNA). Most small RNA research focuses on model plants (e.g. Arabidopsis, tomato and rice), and has identified the function of small RNAs on plant development (e.g. meristem organization, leaf development, flower organ identity and transition to flowering). Recently, small RNA sequencing has been applied to study gene regulation in horticultural crops. Plant specific small RNA (miRNAs and phasiRNAs) families have similar function across model plants to horticultural crops. In addition, most plants have unique nonconserved small RNAs, which might affect specific traits. This review focuses on small RNA biogenesis, function prediction and the roles of small RNAs in horticultural traits (e.g. flowering, fruit quality, abiotic and biotic stress), and summarizes small RNA information for future horticultural crop research and breeding.
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Pub Date : 2020-01-02DOI: 10.1080/07352689.2020.1752439
B. Mieslerová, Miloslav Kitner, E. Křístková, Ľ. Majeský, A. Lebeda
Abstract The present work summarizes important new information and results focused on powdery mildew occurring on the genus Lactuca from a growing body, including long-term research. This plant genus is host to at least three biologically and ecologically different genera of powdery mildew: Golovinomyces (U. Braun) Heluta, Podosphaera Kunze, and Leveillula G. Arnaud. The taxonomy, distribution, morphology, and biology of Golovinomyces bolayi, Podosphaera xanthii, Leveillula lactucae-serriolae, and L. lactucarum are also discussed, along with the threat they pose to Lactuca spp., as well as methods of control. A deeper understanding has only been obtained in the Lactuca spp. – Golovinomyces bolayi pathosystem. The results of 20 years of study into the occurrence of G. bolayi in wild L. serriola populations in the Czech Republic found that the percentage of L. serriola populations infected by G. bolayi (disease incidence) varied considerably between 29 and 75.2% over the reporting period. Although this powdery mildew appears to prefer warmer temperatures (about 20 °C) and lower precipitation, it is hard to discern a direct relationship between meteorological data and disease occurrence. Study of the pathogenic variability of G. bolayi isolates from the Czech Republic between 2008 and 2017 (on a unified and stable differential set of 13 genotypes of genus Lactuca spp.) confirmed that G. bolayi isolates represented different combinations of reaction patterns on the Lactuca spp. differential set. However, isolates virulent on all 13 genotypes (i.e. super-race) were recorded very sporadically. Moving forward, studies of the mechanisms and genetics of resistance are greatly needed.
{"title":"Powdery Mildews on Lactuca Species – A Complex View of Host-Pathogen Interactions","authors":"B. Mieslerová, Miloslav Kitner, E. Křístková, Ľ. Majeský, A. Lebeda","doi":"10.1080/07352689.2020.1752439","DOIUrl":"https://doi.org/10.1080/07352689.2020.1752439","url":null,"abstract":"Abstract The present work summarizes important new information and results focused on powdery mildew occurring on the genus Lactuca from a growing body, including long-term research. This plant genus is host to at least three biologically and ecologically different genera of powdery mildew: Golovinomyces (U. Braun) Heluta, Podosphaera Kunze, and Leveillula G. Arnaud. The taxonomy, distribution, morphology, and biology of Golovinomyces bolayi, Podosphaera xanthii, Leveillula lactucae-serriolae, and L. lactucarum are also discussed, along with the threat they pose to Lactuca spp., as well as methods of control. A deeper understanding has only been obtained in the Lactuca spp. – Golovinomyces bolayi pathosystem. The results of 20 years of study into the occurrence of G. bolayi in wild L. serriola populations in the Czech Republic found that the percentage of L. serriola populations infected by G. bolayi (disease incidence) varied considerably between 29 and 75.2% over the reporting period. Although this powdery mildew appears to prefer warmer temperatures (about 20 °C) and lower precipitation, it is hard to discern a direct relationship between meteorological data and disease occurrence. Study of the pathogenic variability of G. bolayi isolates from the Czech Republic between 2008 and 2017 (on a unified and stable differential set of 13 genotypes of genus Lactuca spp.) confirmed that G. bolayi isolates represented different combinations of reaction patterns on the Lactuca spp. differential set. However, isolates virulent on all 13 genotypes (i.e. super-race) were recorded very sporadically. Moving forward, studies of the mechanisms and genetics of resistance are greatly needed.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1752439","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46728494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-02DOI: 10.1080/07352689.2020.1724433
K. Rathore, D. Pandeya, L. M. Campbell, Thomas C. Wedegaertner, L. Puckhaber, R. Stipanovic, J. Scott Thenell, S. Hague, K. Hake
Abstract The global output of cottonseed contains ∼10.8 trillion grams of protein that can meet the basic protein requirements of ∼590 million people at a rate of 50 g/day. However, gossypol, a toxic terpenoid present in seed glands, renders cottonseed unfit as food for human consumption or as feed for nonruminants. RNAi, under the control of a seed-specific promoter, was used to selectively silence δ-cadinene synthase gene to reduce gossypol levels in the seed by 97% without affecting the levels of gossypol and related terpenoids in rest of the plant where they are needed for defense against insects and diseases. The resulting Ultra-low Gossypol Cottonseed (ULGCS) is considered safe as food or as feed for more efficient (both, in terms of feed conversion ratio and protein conversion ratio) monogastric animals. Field trials conducted over multiple years in multiple states confirm the stability and heritability of the trait with no diminution of fiber/seed yield, quality or agronomic performance. A ULGCS event, TAM66274, was deregulated by USDA-APHIS in October 2018 and FDA concluded its food safety consultation in September 2019 and concurred with our determination of its safety. Global adoption of TAM66274, with more efficient and expanded usage of its protein, has the potential to significantly improve nutrition security and boost farmers’ income without requiring additional inputs or acreage under cultivation, thus making cotton farming more sustainable.
{"title":"Ultra-Low Gossypol Cottonseed: Selective Gene Silencing Opens Up a Vast Resource of Plant-Based Protein to Improve Human Nutrition","authors":"K. Rathore, D. Pandeya, L. M. Campbell, Thomas C. Wedegaertner, L. Puckhaber, R. Stipanovic, J. Scott Thenell, S. Hague, K. Hake","doi":"10.1080/07352689.2020.1724433","DOIUrl":"https://doi.org/10.1080/07352689.2020.1724433","url":null,"abstract":"Abstract The global output of cottonseed contains ∼10.8 trillion grams of protein that can meet the basic protein requirements of ∼590 million people at a rate of 50 g/day. However, gossypol, a toxic terpenoid present in seed glands, renders cottonseed unfit as food for human consumption or as feed for nonruminants. RNAi, under the control of a seed-specific promoter, was used to selectively silence δ-cadinene synthase gene to reduce gossypol levels in the seed by 97% without affecting the levels of gossypol and related terpenoids in rest of the plant where they are needed for defense against insects and diseases. The resulting Ultra-low Gossypol Cottonseed (ULGCS) is considered safe as food or as feed for more efficient (both, in terms of feed conversion ratio and protein conversion ratio) monogastric animals. Field trials conducted over multiple years in multiple states confirm the stability and heritability of the trait with no diminution of fiber/seed yield, quality or agronomic performance. A ULGCS event, TAM66274, was deregulated by USDA-APHIS in October 2018 and FDA concluded its food safety consultation in September 2019 and concurred with our determination of its safety. Global adoption of TAM66274, with more efficient and expanded usage of its protein, has the potential to significantly improve nutrition security and boost farmers’ income without requiring additional inputs or acreage under cultivation, thus making cotton farming more sustainable.","PeriodicalId":10854,"journal":{"name":"Critical Reviews in Plant Sciences","volume":null,"pages":null},"PeriodicalIF":6.9,"publicationDate":"2020-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/07352689.2020.1724433","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46186332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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