Biology subjects

Cakmak, I.

Publications and source records attributed to Cakmak, I..

3 recordsLinked to original sources

bioRxiv2019

Population-specific effect of Wolbachia on the cost of fungal infection in spider mites

Many studies have revealed the ability of the endosymbiotic bacteria Wolbachia to protect its arthropod hosts against diverse pathogens. However, as Wolbachia may also increase the susceptibility of its host to infection, predicting the outcome of a particular Wolbachia-host-pathogen interaction remains elusive. Yet, understanding such interactions is crucial for disease and pest control strategies. Tetranychus urticae spider mites are herbivorous crop pests, causing severe damage on numerous economically important crops. Due to the rapid evolution of pesticide resistance, biological control strategies using generalist entomopathogenic are being developed. However, although spider mites are infected with various Wolbachia strains worldwide, whether this endosymbiont protects them from fungi is as yet unknown. Here, we compared the survival of two populations, treated with antibiotics or harbouring different Wolbachia strains, after exposure to the fungal biocontrol agents Metarhizium brunneum and Beauveria bassiana. In one population, Wolbachia affected survival in absence of fungi but not in their presence, whereas in the other population Wolbachia increased the mortality induced by B. bassiana. To control for potential effects of the bacterial community of spider mites, we also compared the susceptibility of two populations naturally uninfected by Wolbachia, treated with antibiotics or not. The antibiotic treatment increased the susceptibility of spider mites to M. brunneum in one naturally Wolbachia-uninfected population, but it had no effect in the other treatments. These results highlight the complexity of within-host pathogens interactions, and the importance of considering the whole bacterial community of arthropods when assessing the effect of Wolbachia in a particular system.

ecology↗

bioRxiv2019

Inter- and intra-specific variation of spider mite susceptibility to fungal infections: implications for the long-term success of biological control

Spider mites are severe pests of several annual and perennial crops worldwide, often causing important economic damages. Moreover, rapid evolution of pesticide resistance in this group hampers the efficiency of chemical control. Alternative control strategies, such as the use of entomopathogenic fungi, are thus being developed. However, while several studies have focussed on the evaluation of the control potential of different fungal species and/or isolates as well as their compatibility with other control methods (e.g. predators or chemical pesticides), knowledge on the extent of inter- and intraspecific variation in spider mite susceptibility to fungal infection is as yet incipient. Here, we measured the mortality induced by two generalist fungi, Beauveria bassiana and Metarhizium brunneum, in 12 spider mite populations belonging to different Tetranychus species: T. evansi, T. ludeni, the green form of T. urticae and the red form of T. urticae, within a full factorial experiment. We found that spider mite species differed in their susceptibility to infection to both fungal species. Moreover, we also found important intraspecific variation for this trait. These results draw caution on the development of single strains as biocontrol agents. Indeed, the high level of intraspecific variation suggests that (a) the one-size-fits-all strategy will probably fail to control spider-mite populations and (b) hosts resistance to infection may evolve at a rapid pace. Finally, we propose future directions to better understand this system and improve the long-term success of spider mite control strategies based on entomopathogenic fungi.

ecology↗

bioRxiv2019

Variation in phosphorus and sulfur content shapes the genetic architecture and phenotypic associations within wheat grain ionome

Dissection of the genetic basis of ionome is crucial for the understanding of the physiological and biochemical processes underlying mineral accumulation in seeds, as well as for efficient crop breeding. Most of the elements essential for plants are metals stored in seeds as chelate complexes with phytic acid or sulfur-containing compounds. We assume that the involvement of phosphorus and sulfur in metal chelation is the reason for strong phenotypic associations within ionome. Thus, we adjusted element concentrations for the effect of variation in phosphorus and sulfur seed content. The genetic architecture of wheat grain ionome was characterize by QTL analysis using a cross between durum and wild emmer wheat. Adjustment for variation in P and S drastically changed phenotypic associations within ionome and considerably improved QTL detection power and accuracy, resulting in identification of 105 QTLs and 437 QTL effects for 11 elements. A search for candidate genes revealed some strong functional associations of genes involved in transport and metabolism of ions and elements. Thus, we have shown that accounting for variation in P and S is crucial for understanding of the physiological and genetic regulation of mineral composition of wheat grain ionome and can be implemented for other plants.

genetics↗