ABSTRACT
This study aims to elucidate if the regulation of plant aquaporins by the arbuscular mycorrhizal (AM) symbiosis occurs only in roots or cells colonized by the fungus or at whole root system. Maize plants were cultivated in a split-root system, with half of the root system inoculated with the AM fungus and the other half uninoculated. Plant growth and hydraulic parameters were measured and aquaporin gene expression was determined in each root fraction and in microdissected cells. Under well-watered conditions, the non-colonized root fractions of AM plants grew more than the colonized root fraction. Total osmotic and hydrostatic root hydraulic conductivities (Lo and Lpr) were higher in AM plants than in non-mycorrhizal plants. The expression of most maize aquaporin genes analysed was different in the mycorrhizal root fraction than in the non-mycorrhizal root fraction of AM plants. At the cellular level, differential aquaporin expression in AM-colonized cells and in uncolonized cells was also observed. Results indicate the existence of both, local and systemic regulation of plant aquaporins by the AM symbiosis and suggest that such regulation is related to the availability of water taken up by fungal hyphae in each root fraction and to the plant need of water mobilization.
ABSTRACT
Orchid mycorrhiza (OM) represents an unusual symbiosis between plants and fungi because in all orchid species carbon is provided to the host plant by the mycorrhizal fungus at least during the early stages of orchid development, named a protocorm. In addition to carbon, orchid mycorrhizal fungi provide the host plant with essential nutrients such as phosphorus and nitrogen. In mycorrhizal protocorms, nutrients transfer occurs in plant cells colonized by the intracellular fungal coils, or pelotons. Whereas the transfer of these vital nutrients to the orchid protocorm in the OM symbiosis has been already investigated, there is currently no information on the transfer of sulfur (S). Here, we used ultra-high spatial resolution secondary ion mass spectrometry (SIMS) as well as targeted gene expression studies and laser microdissection to decipher S metabolism and transfer in the model system formed by the Mediterranean orchid Serapias vomeracea and the mycorrhizal fungus Tulasnella calospora. We revealed that the fungal partner is actively involved in S supply to the host plant, and expression of plant and fungal genes involved in S uptake and metabolism, both in the symbiotic and asymbiotic partners, suggest that S transfer most likely occurs as reduced organic forms. Thus, this study provides original information about the regulation of S metabolism in OM protocorms, adding a piece of the puzzle on the nutritional framework in OM symbiosis.
ABSTRACT
Thrombotic thrombocytopenic purpura (TTP) is a rare and life-threatening disease for which pregnancy and the postpartum period represent risk factors. Here, we present the case of a 39-year-old woman at the 31st week of gestation, who presented with cutaneous haemorrhagic symptoms. The complete blood count showed anaemia, thrombocytopenia, increase in haemolysis indices and undetectable ADAMTS13 activity. Acquired TTP was diagnosed, and she started daily plasma exchange (PEX) and methylprednisolone. After 5âdays, an emergency caesarean section was performed with success because of pathologic cardiotocographic findings. After 7 days of PEX, the patient showed an initial laboratoristic improvement; unfortunately, 3 days later, she had a recurrence of disease and started daily PEX, caplacizumab and steroid, obtaining a haematological improvement. No literature data about caplacizumab use in pregnant or breastfeeding patients are available. In the present study, we describe that caplacizumab in the postpartum period could be well tolerated and effective.
