## 1 Introduction  
The global market for legumes has been growing steadily since the 1960s, driven by their high protein content and the increasing demand for sustainable diets [1, 2, 3]. Legumes play a crucial role in providing essential nutrients and are a key component of environmentally friendly agricultural practices. The globalization of the market in recent decades has facilitated the unregulated movement of plant materials and goods across continents, including the international trade of legumes. However, this has inevitably contributed to the increased spread of plant pathogens into geographical regions where they were previously absent and where they can find new hosts, thus boosting the risk of epidemic outbreaks. Among the major emerging seed-borne pathogens is _Curtobacterium flaccumfaciens_ pv. _flaccumfaciens_ (_Cff_), a Gram-positive bacterium, known for causing bacterial wilt in leguminous crops. Initially observed in the USA in the 1920s, _Cff_ has since spread globally, impacting crops such as common bean, mung bean, cowpea, and soybean [4; 5; 6]. _Cff_ is a vascular pathogen that systemically colonizes its host plants, surviving in plant residues and entering plants through contaminated seeds or wounds [5; 7; 8; 9; 10]. Disease severity intensifies during hot and dry periods, due to the in planta localization of _Cff_ and its impact on the functionality of the xylem [11]. _Cff_-infected seeds can appear discolored, exhibiting yellow, orange, pink, red, or purple hues, particularly in white-seeded bean cultivars, depending on the pigmentation of the different _Cff_ strains [6; 11; 12; 13; 14]. The percentage of discolored, symptomatic bean seeds can range from 0 to 25%, as observed in field experiments in Canada and the USA [10; 15]. In North America, outbreaks were sporadic until the late 20 th century, when a resurgence occurred, impacting crops such as mung bean and cowpea in Australia, and soybean in South America. The pathogen's presence has also been documented in Asia and Africa, with recent reports in Europe requiring urgent and stringent quarantine measures to prevent its further spread [7; 16; 17; 18; 19; 20; 21; 22; 23]. In fact, _Cff_ is included in the list of A1 quarantine pests as part of Commission Implementing Regulation (EU) 2019/2072, Annex II A, by the European Union [24], and in the A2 list of quarantine plant pathogens drawn up by the European and Mediterranean Plant Protection Organization (EPPO), due to its high phytosanitary significance [25]. Recent reports highlight the adaptability of _Cff_ to diverse environmental conditions, emphasizing the need for robust surveillance and diagnostic tools to mitigate economic losses. Detecting _Cff_ is challenging due to its long latent period in regard to infected plant materials, slow growth, and endophytic nature [26]. Various methods, including visual inspection, numerical taxonomy, serology, and PCR fingerprinting, have been employed with varying success [27; 28]. Despite these diagnostic advancements, early detection remains challenging, impacting quarantine measures and seed certification protocols. Recent advancements in PCR-based methods offer improved sensitivity and specificity, but challenges remain in accurately identifying and controlling the pathogen [29; 30]. Emerging non-destructive techniques, such as photoacoustic detection, hold promise for addressing these challenges by offering rapid, high-throughput screening, and sensitive diagnostics for seed-borne pathogens, including _Cff_[31]. On the other hand, volatile organic compounds (VOCs) produced by phytopathogenic bacteria represent an emerging area of research, with highly significant diagnostic potential. These low molecular weight organic molecules, with high vapor pressures at room temperature, play a crucial role in plant-microbe interactions, influencing plant physiology and their natural defenses [32]. For at least four decades, VOCs have been well-known as part of plant defense strategies, both direct and indirect, against herbivores [33; 34].