## 1 Introduction  
P phytopathogen infection leads to changes in plant physiology. They involve both secondary metabolism based on inducing the defense programs of a plant as well as primary metabolism, which affects the growth and development of the plant [1]. It is known that both microorganisms and plants emit volatile compounds, including odors that are characteristic of a particular species. These compounds are released as an effect of pathogen activity, and therefore can serve as markers of microbial contamination. Potato flavor has been extensively studied due to its importance in nutrition: volatile compounds predominantly include aldehydes, alcohols, ketones, acids, esters, hydrocarbons, amines, furans, and sulfur compounds. However, the pattern and volatility of the components released from potatoes can differ significantly, depending on whether potatoes are raw or cooked. Moreover, potato pathogens: fungi, bacteria, parasitic plants, viruses, nematodes, and protozoa can modify the volatile pattern emitted from pathogenic species. Potatoesinoculated with pathogens produce volatile molecules that can be considered as the markers of infection [2]. Despite the knowledge on potato volatilome, there is a lack of expertise on volatile compounds emitted from pathogen cultures growing onto potatoes. These microbial volatile products, such as alcohols, ketones, terpenoids, esters, and others, can also be used as the markers of microbial contamination. Microbial volatile organic compounds (mVOCs) are carbon-based, secondary metabolites of molds and bacteria characterized by low molecular mass, and easy evaporation allowing their easy disperse in the atmosphere. Most of them produce distinctive odors [3]. More than 1800 unique bacterial and fungal VOCs have been so far reported in the literature [4]. Dozens or even hundreds of microbial volatile organic compounds are produced by the same microorganisms, but some of them are related to specific fungal or bacterial metabolism [5]. The composition of VOCs significantly differs between two species of molds and even two isolates belonging to the same species [6]. Except strain specify, volatile production is also influenced by growth medium, incubation time, humidity, and temperature [7]. In addition, for plant VOC, this volatile compound profile is specific for different varieties of the same plant species [8]. Some volatile compounds were identified as potential indicators of microbial plant infection. For example, menthol and menthoe have been reported as potential markers of açi pulp infection with the genus _Colletotrichum_[9]. This mold is also responsible for black dot disease of potatoes [10]. In turn, ethanol, ethyl formate, ethyl acetate, and four other mVOCs were indicated as markers of onion infestation by _Fusarium_ species [6]. Volatile organic compounds determination in the early stage of pathogen infection was found to be useful in preventing risk of mycotoxin production on wheat [11] and walnut [12] by toxicogenic _Aspergillus_, _Fusarium_, and _Penicillium_ species. [PERSON] and co-workers [13] distinguished crop infection with _A. flavus_ strain (aflatoxin B1 producer) from non-toxicogenic strain by mVOCs evaluation. Despite the data relating to the markers of different plants, there is a lack of reliable and commonly used markers assessing the physiological activity, seed value, and yield potential of seed potatoes, which would allow to quickly demonstrate the effects of various treatments, predict plant growth in the field, and be an alternative to long-term and costly field tests. These markers are particularly desirable for monitoring the yield potential of seed potatoes treated against disease, pests, and aging. Moreover, identification of the relationship between selected metabolic processes in stored or treated potato tubers and plant development may be useful in forecasting methods for early recognition of the quality of seed potatoes and their yielding potential [14].