Microbial communities have an important role in health and disease. Candida spp. are ubiquitous commensals and sometimes opportunistic fungal pathogens of humans, colonizing mucosal surfaces of the genital, urinary, respiratory and gastrointestinal tracts and the oral cavity. They mainly cause local mucosal infections in immune competent individuals. However, in the case of an ineffective immune defense, Candida infections may become a serious threat. Lactobacillus spp. are part of the human microbiome and are natural competitors of Candida in the vaginal environment. Lactic acid, low pH and other secreted metabolites are environmental signals sensed by fungal species present in the microbiome. This review briefly discusses the ternary interaction between host, Lactobacillus species and Candida with regard to fungal infections and the potential antifungal and fungistatic effect of Lactobacillus species. Our understanding of these interactions is incomplete due to the variability of the involved species and isolates and the complexity of the human host.

Root hairs are able to sense soil composition and play an important role for water and nutrient uptake. In Arabidopsis thaliana, root hairs are distributed in the epidermis in a specific pattern, regularly alternating with non-root hair cells in continuous cell files. This patterning is regulated by internal factors such as a number of hormones, as well as external factors like nutrient availability. Thus, root hair patterning is an excellent model for studying the plasticity of cell fate determination in response to environmental changes. Here, we report that loss-of-function mutants in the Protein O-fucosyltransferase, SPINDLY (SPY) show defects in root hair patterning. Using transcriptional reporters, we show that patterning in spy-22 is affected upstream of the GLABRA2 (GL2) and WEREWOLF (WER). O-fucosylation of nuclear and cytosolic proteins is an important post-translational modification that is still not very well understood. So far, SPY is best characterized for its role in gibberellin signaling via fucosylation of the growth-repressing DELLA protein REPRESSOR OF ga1-3 (RGA). Our data suggests that the epidermal patterning defects in spy-22 are independent of RGA and gibberellin signaling.

Several Candida species are opportunistic human fungal pathogens and thrive in various environmental niches in and on the human body. In this study we focus on the conditions of the vaginal tract, which is acidic, hypoxic, glucose-deprived, and contains lactic acid. We quantitatively analyze the lactic acid tolerance in glucose-rich and glucose-deprived environment of five Candida species: Candidaalbicans, Candida glabrata, Candida parapsilosis, Candida krusei and Candida tropicalis. To characterize the phenotypic space, we analyzed 40–100 clinical isolates of each species. Each Candida species had a very distinct response pattern to lactic acid stress and characteristic phenotypic variability. C. glabrata and C. parapsilosis were best to withstand high concentrations of lactic acid with glucose as carbon source. A glucose-deprived environment induced lactic acid stress tolerance in all species. With lactate as carbon source the growth rate of C. krusei is even higher compared to glucose, whereas the other species grow slower. C. krusei may use lactic acid as carbon source in the vaginal tract. Stress resistance variability was highest among C. parapsilosis strains. In conclusion, each Candida spp. is adapted differently to cope with lactic acid stress and resistant to physiological concentrations.

11Root hairs are able to sense soil composition and play an important role for water and nutrient uptake. 12In Arabidopsis thaliana, root hairs are distributed in the epidermis in a specific pattern, regularly 13 alternating with non-root hair cells in continuous cell files. This patterning is regulated by internal 14 factors such as a number of hormones, as well as external factors like nutrient availability. Thus, root-15 hair patterning is an excellent model for studying the plasticity of cell fate determination in response 16 to environmental changes. Here, we report that loss-of-function mutants in the Protein O-17 Fucosyltransferase SPINDLY (SPY) form ectopic root hairs. Using a number of transcriptional reporters, 18we show that patterning in spy-22 is affected upstream of the central regulators GLABRA2 (GL2) and 19 WEREWOLF (WER). O-fucosylation of nuclear and cytosolic proteins is an important post-translational 20 modification that is still not very well understood. So far, SPY is best characterized for its role in 21 gibberellin signalling via fucosylation of the growth-repressing DELLA protein REPRESSOR OF GA 22 (RGA). Our data suggest that the formation of ectopic root hairs in spy-22 is independent of RGA and 23 gibberellin signalling. 24

The timing of plant developmental transitions is decisive for reproductive success and thus tightly regulated by a number of pathways with a high degree of crosstalk between them. Such complex regulatory pathways often involve post-translational modifications (PTMs), integrating internal and environmental signals. O-glycosylation, the attachment of a single monosaccharide to serine or threonine of nuclear and cytosolic proteins, is one of these PTMs, affecting a number of very diverse proteins. Here we show that mutants in the Ofucosyltransferase SPINDLY (SPY) show accelerated developmental transitions. In plants, the transition from juvenile to adult and later to reproductive phase is controlled by an endogenous pathway regulated by miR156, targeting the SQUAMOSA PROMOTER BINDING PROTEIN (SBP/SPL) family of transcription factors. SPLs regulate a number of developmental processes, such as trichome formation, leaf shape, leaf growth rate and floral transition. We present genetic analysis showing that O-glycosylation regulates transitions independently of miR156 levels, but depending on functional SPLs. Moreover, SPLs interact directly with SPY and are O-glycosylated. Our results suggest a model where O-glycosylation is involved at several steps in the regulation of developmental transitions, and plays an important role in fine-tuning different regulatory pathways.