## 1 Introduction  
The seedling stage is considered to be one of the phases most sensitive to external stimuli in the plant life cycle. Those seedlings are susceptible in the soil to physical injuries, and thus to microbial infections, especially to fungal decay [1]. As with all plants, cereals produce protective antimicrobial secondary metabolites, either as part of their normal program of growth and development (phytoanticipins) or in response to a pathogen attack or stress (phytoalexins). Phytoanticipins, so-called preformed antimicrobial compounds, are biosynthesized constitutively in healthy plants. These substances form a chemical barrier against attack by various phytopathogenic organisms [2]. Resorcinolic lipids and their derivatives are found in cereal plants in both germinated caryopses and their seedlings [3; 4; 5]. [PERSON] et al. [6], for example, showed the presence of alkylresorcinol synthase in all above-ground organs of rye. However, mature, ungermented grains are the richest source of these secondary metabolites [3; 4]. Interestingly, 5-\(n\)-alk(en)lyresorcinols are located only in the outer layers of caryopses (Figure 1). They are found in both the outer and intermediate parts of the caryopsis, including the hyaline layer, testa, inner pericarp, and the cuticle of the pericarp [7; 8; 9]. In general, the amount of resorcinol lipids in cereal grains is higher in rye (_Secale cereale_ L.), lower in wheat (_Triticum aestivum_ L.) and triticale (_Triticoscale_ Wittm. [PERSON]), and lowest in other cereals such as barley (_Hordeum distich_ L.) and oat _Avena sativa_ L.) [10; 11; 12; 13; 14]. A large amount of these compounds has also recently been identified in other cereals such as einkorn (_Triticum monocytogenes_ L. subsp. _monococcum_), emmer (_Triticum turgidum_ L. subsp. _dicoccum_ (Schrank ex [PERSON].) [PERSON]), spelt (_Triticum aestivum_ L. subsp. _spelta_ (L.) [PERSON]), and tritordeum (\(\times\)_Tritordeum martini_ A. [PERSON]) [8]. Regarding their chemical nature, resorcinol lipids, also called 5-\(n\)-alk(en)ylresorcinols (ARs), are long-chain, odd-numbered homologues of orcinol (1,3-dihydroxy-5-methylbenzene) that originate from the polyketide metabolic pathway [15]. These isoprenoid phenolic lipids in cereals are present as mixtures of saturated and unsaturated homologues with 13-29 carbons in the chain, including the oxidized and hydroxylated forms [10; 11; 12; 13; 14; 15; 16]. However, both the content and homologue composition of this class of phenolic lipids in cereals can vary widely between variety and species due to environmental, agricultural, and genetic factors [8; 17; 18; 19; 20]. Under in vitro conditions, the effects of various external factors, especially light, temperature, and pesticides, on the biosynthesis of these compounds have been described [21; 22; 23]. Resorcinolic lipids are potent antimicrobials and therefore they are often called natural biofungicides [24]. Hitherto, their antifungal activity, mainly against ascomycetous pathogens of the genera _Aspergillus_, _Penicillium_, and _Fusarium_, has been demonstrated [24; 25; 26; 27]. Among several microbes affecting the development of cereal seedlings, infections caused by _Fusarium calumorum_ ([PERSON]) [PERSON] and _Rhizoctonia solani_ [PERSON] are some of the most deleterious. _Rhizoctonia solani_ is the main agent of Rhizoctonia stunt in cereals and it can be responsible for seedling rot. In turn, _F. culmorum_ is a ubiquitous soil-borne fungus able to cause foot and root rot (Fusarium crown rot) and scab (Fusarium head blight; FHB) on different small-grain cereals, in particular on wheat and barley [28; 29]. Interestingly, [PERSON] et al. [30] reported that _Fusarium_ mycotoxin content, being the sum of deoxynivalenol and its glucoside, is negatively correlated with the AR level in the cryopses of _Triticum_ spp.