scholarly journals Homo- and Dikaryons of the Arbuscular Mycorrhizal Fungus Rhizophagus irregularis Differ in Life History Strategy

2021 ◽  
Vol 12 ◽  
Author(s):  
Edward Umberto Serghi ◽  
Vasilis Kokkoris ◽  
Calvin Cornell ◽  
Jeremy Dettman ◽  
Franck Stefani ◽  
...  

Arbuscular mycorrhizal fungi (AMF) are obligate plant symbionts that have the potential to improve crop yield. These multinucleate organisms are either “homokaryotic” or “dikaryotic”. In AMF dikaryons, thousands of nuclei originating from two parental strains coexist in the same cytoplasm. In other fungi, homokaryotic and dikaryotic strains show distinct life history traits (LHTs), such as variation in growth rates and fitness. However, how such traits compare between dikaryons and homokaryons of AMF is unknown. To address this, we measured 20 LHT of four dikaryons and five homokaryons of the model fungus Rhizophagus irregularis across root organ cultures of three host plants (carrot, chicory, and tobacco). Our analyses show that dikaryons have clearly distinct life history strategies (LHSs) compared to homokaryons. In particular, spores of homokaryons germinate faster and to a higher proportion than dikaryons, whereas dikaryons grow significantly faster and create a more complex hyphal network irrespective of host plant species. Our study links AMF nuclear status with key LHT with possible implications for mycorrhizal symbiotic functioning.

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Anurag Chaturvedi ◽  
Joaquim Cruz Corella ◽  
Chanz Robbins ◽  
Anita Loha ◽  
Laure Menin ◽  
...  

AbstractEarly-diverging fungi (EDF) are distinct from Dikarya and other eukaryotes, exhibiting high N6-methyldeoxyadenine (6mA) contents, rather than 5-methylcytosine (5mC). As plants transitioned to land the EDF sub-phylum, arbuscular mycorrhizal fungi (AMF; Glomeromycotina) evolved a symbiotic lifestyle with 80% of plant species worldwide. Here we show that these fungi exhibit 5mC and 6mA methylation characteristics that jointly set them apart from other fungi. The model AMF, R. irregularis, evolved very high levels of 5mC and greatly reduced levels of 6mA. However, unlike the Dikarya, 6mA in AMF occurs at symmetrical ApT motifs in genes and is associated with their transcription. 6mA is heterogeneously distributed among nuclei in these coenocytic fungi suggesting functional differences among nuclei. While far fewer genes are regulated by 6mA in the AMF genome than in EDF, most strikingly, 6mA methylation has been specifically retained in genes implicated in components of phosphate regulation; the quintessential hallmark defining this globally important symbiosis.


Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 161
Author(s):  
Yuki Ogura-Tsujita ◽  
Kenshi Tetsuka ◽  
Shuichiro Tagane ◽  
Miho Kubota ◽  
Shuichiro Anan ◽  
...  

Mycoheterotrophic orchids depend completely on mycorrhizal fungi for their supply of carbon. The life-history traits of mycoheterotrophic plants (MHPs) can differ according to the characteristics of the associated mycorrhizal fungi. We compared the life-history strategies of two mycoheterotrophic orchids associated with wood- and leaf litter-decaying fungi over a maximum of six years of field monitoring. Seventy percent of the aboveground stems of Erythrorchis altissima, associated with wood-decaying fungi, disappeared from the host wood within two years after tagging, likely due to nutrient depletion. In contrast, Gastrodia confusa, associated with leaf litter-decaying fungi, occurred continuously (18 to 108 fruiting stalks) every year within a small-scale plot (12 × 45 m) for six years through seed and clonal propagation. Our results support the idea that mycoheterotrophic orchids associated with wood-decaying fungi disappear from their habitats due to nutrient depletion after their host wood has mostly decayed, while mycoheterotrophic orchids associated with leaf litter-decaying fungi can survive in small-scale habitats where substantial leaf fall regularly occurs to sustain the associated fungi. Our study provides basic information about a unique life-history strategy in MHPs associated with saprotrophic fungi and an understanding of the variation in life-history strategies among MHPs.


2020 ◽  
Author(s):  
Rebecca Sear

Interest in incorporating life history research from evolutionary biology into the human sciences has grown rapidly in recent years. Two core features of this research have the potential to prove valuable in strengthening theoretical frameworks in the health and social sciences: the idea that these is a fundamental trade-off between reproduction and health; and that environmental influences are important in determining individual life histories. For example, the idea that mortality risk in the environment shifts individuals along a ‘fast-slow continuum’ of ‘life history strategy’ is now popular in the evolutionary human sciences. In biology, ‘fast’ life history strategists prioritise reproduction over health so that individuals grow quickly, reproduce early and often, and suffer a rapid deterioration in health and relatively early death; ‘slow’ strategists start reproducing later, have fewer offspring, and die at an older age. Evolutionary human scientists tend to assume that, along with these life history outcomes, several behavioural traits, such as parenting, mating and risk-taking behaviour and, in the most expansive version, a whole suite of psychological and personality traits also cluster together into ‘fast’ and ‘slow’ life histories. Here, I review the different approaches to life history strategies from evolutionary anthropologists, developmental psychologists and evolutionary psychologists, in order to assess the theoretical and empirical evidence for human ‘life history strategies’. While there is precedent in biology for the argument that some behavioural traits, notably risk-taking behaviour, may be linked in predictable ways with life history outcomes, there is relatively little theoretical or empirical justification for including a very wide range of behavioural traits in a ‘life history strategy’. Given the diversity and lack of consistency in this human life history literature, I then make recommendations for improving its usefulness: 1) greater clarity over terminology, so that a distinction is made between life history outcomes such as age at maturity, first birth and death, and behavioural traits which may be associated with life history outcomes but are not life history traits themselves; 2) more empirical data on linkages between life history traits, behavioural traits and the environment, including the underlying mechanisms which generate these linkages; 3) more empirical work on life history strategies in a much broader range of populations than has so far been studied. Such a research programme on human life history has the potential to produce valuable insights for the health and social sciences, not least because of its interest in environmental influences on health, reproduction and behaviour.


2003 ◽  
Vol 53 (1) ◽  
pp. 47-57 ◽  
Author(s):  
◽  

AbstractSeven life-history traits were used to describe the life-history strategies of 12 native and introduced species from a permanent lake in Spain. Multivariate analysis identified a continuum of life-history patterns between two extremes: 1) species with one or few spawnings per year, short breeding season, long generation time, large size, high fecundity, and no parental care. This set of life-history traits corresponded to the periodic life-history strategy described by Winemiller (1989) and Winemiller and Rose (1992); and 2) species with multiple spawnings per year, prolonged breeding season, short generation time, small size, low fecundity, parental care, and small to medium size of eggs. This association of life-history traits corresponded to the opportunistic life-history strategy described by Winemiller (1989) and Winemiller and Rose (1992). It seems that there were no apparent differences in life-history strategies between native and introduced species in Lake Banyoles. Native and introduced species were found among periodic and opportunistic strategists. Observed differences in the success of native and introduced species with comparable life-history strategies seems to suggest that the success of fish species in Lake Banyoles could not be explained on the basis of life-history features. Nevertheless, it seems that successful invasive species in Lake Banyoles display a suite of traits such as high fecundity, late maturity, and large body size. These characteristics may perhaps be viewed as biological predictors of successful invaders but more information is needed about life-history features of successful introduced species from other ecosystems.


2020 ◽  
Author(s):  
Henry Cheeld ◽  
Govindprasad Bhutada ◽  
Frederic Beaudoin ◽  
Peter J Eastmond

AbstractArbuscular mycorrhizal fungi are oleaginous organisms and the most abundant fatty acyl moiety usually found in their lipids is palmitvaccenic acid (16:1Δ11cis). However, it is not known how this uncommon fatty acid species is made. Here we have cloned two homologs of Lepidopteran fatty acyl-CoenzymeA Δ11 desaturases from Rhizophagus irregularis. Both DES1 and DES2 are expressed in intraradicle mycelium and can complement the unsaturated fatty acid-requiring auxotrophic growth phenotype of the Saccharomyces cerevisiae ole1Δ mutant. DES1 expression leads almost exclusively to oleic acid (18:1Δ9cis) production, whereas DES2 expression results in the production of 16:1Δ11cis and vaccenic acid (18:1Δ11cis). DES2 therefore encodes a Δ11 desaturase that is likely to be responsible for the synthesis of 16:1Δ11cis in R. irregularis.


2010 ◽  
Vol 67 (8) ◽  
pp. 1640-1649 ◽  
Author(s):  
Graham D. Sherwood ◽  
Jonathan H. Grabowski

Abstract Sherwood, G. D., and Grabowski, J. H. 2010. Exploring the life-history implications of colour variation in offshore Gulf of Maine cod (Gadus morhua). – ICES Journal of Marine Science, 67: 1640–1649. The evolution of alternative life-history strategies in fish has largely been overlooked by fisheries managers, although differences in the biology of life-history variants can have important implications for the scale and productivity of fisheries. Cod display strikingly variable colouration in the Gulf of Maine, with red- and olive-coloured cod found in close sympatry. Colour types from Cashes Ledge, a shallow, offshore (∼100 km) feature, are examined to see whether they differ in key life-history traits including diet, depth distribution, growth, and body morphology. Red cod consumed significantly more crabs, lobsters, and demersal fish, whereas olive cod consumed more shrimp. Stable carbon isotope signatures (δ13C) varied significantly among colour types, but are thought to reflect baseline differences in δ13C at Cashes Ledge (potentially useful for residence estimates). Red cod were confined to a small area of shallow water (<20 m) and were significantly smaller at age than olive cod. Body shape was used to classify colour types correctly with 84% accuracy; red cod had shorter snouts, deeper bodies, and more slender tails than olive cod. Collectively, the results suggest that red cod are resident at Cashes Ledge and represent a life-history strategy distinct from olive cod.


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