Molecular Pathogens, 2025, Vol.16, No.4, 182-192 http://microbescipublisher.com/index.php/mp 188 studies have found that there are significant differences in disease-resistant gene reserves between Eurasian species and wild species: the pan-genome analysis of Guo et al. (2024) revealed that the number and diversity of NBS-LRRdisease-resistant genes in the genome of wild vines is significantly higher than that of cultivated grapes. This "rich-poor gap" of disease-resistant genes is believed to directly lead to differences in disease-resistant phenotypes (Guo et al., 2024). Specifically, Muscadinia rotundifolia in the Americas is almost immune to downy mildew, and its leaves almost never show downy mildew spots; another type of North American wild species such as riparian grapes (V. riparia) and sandy grapes (V. rupestris), also show high or medium resistance, and only mild symptoms appear under extreme high pressure. In contrast, most Eurasian varieties such as Cabernet Sauvignon and Chardonnay are highly sensitive. If the leaves are not sprayed in time in popular years, they are likely to suffer from illness and death (Toffolatti et al., 2018). Wild mountain grapes (V. amurensis) and hairy grapes (V. davidii) in Asia are also relatively resistant to disease, and many wild resources are almost no obvious disease in the fields. The leaves of this type of wild species generally have thicker cuticles and smaller stomatal density (Zhao et al., 2023), which helps to mechanically hinder the invasion of downy mildew bacteria. In addition, they can quickly develop allergic reactions and accumulate antibacterial substances when infected with bacteria, making the pathogen unable to expand. On the contrary, because the Eurasian grapes lack the pressure of downy mildew bacteria in evolution, they do not retain enough resistance to disease variation, and their leaf tissues are almost "unpreventable" from pathogen invasion, and bacteria can reproduce freely in it. 6.2 Case of resistance to grape varieties in the Americas and Asia launched interspecies hybridization practices very early, creating many hybrid grape varieties that are resistant to downy mildew. After the downy mildew disaster in the late 19th century, Europe introduced North American disease-resistant species to hybridize with Eurasian species, and cultivated a series of famous disease-resistant hybrid species. ‘Seyval’ and ‘Villard blanc’, etc., bred in France, contain riparian grapes and Eurasian ancestry, and are highly resistant to downy mildew and powdery mildew (Figure 2) (Wingerter et al., 2021). The ‘Regent’ bred in Germany is a red wine grape variety obtained from complex hybridization of Eurasian species x American species. It carries the Rpv3 resistance gene and is moderately resistant to downy mildew, which significantly reduces the number of sprays. Italy has created disease-resistant varieties such as ‘Bronner’ and ‘Solaris’ by introducing resistance to round leaf grapes. Figure 2 Hydrogen peroxide production at Plasmopara viticola infection sites. P. viticola (avrRpv+) was used to inoculate leaf discs of susceptible genotype (´Müller-Thurgau´) and resistant Rpv3- (´Regent´), Rpv12- (´Fleurtai´) and Rpv12/Rpv3-genotype (´Sauvignac´). Samples were taken at 0, 2, 4, 6, 8, 10, 12, 24, 28, 32 and 36 hpi. Asterisks mark 3, 3′-diaminobenzidine-tetrahydrochloride stained cells indicating hydrogen peroxide formation. Images are representative of three biological replicates in three independent experiments (n = 9). Scale bars correspond to 50 μm (Adopted from Wingerter et al., 2021) China and Russia have long attached great importance to the cold and disease-resistant advantages of East Asian wild mountain grapes. In the second half of the 20th century, China used V. amurensis as its parent to cross with European and American species, and developed a group of wine grape varieties that are both cold and disease-resistant, such as ‘Beijing Red’, ‘Beijing’, ‘Shan Lan’, etc. These varieties are generally highly resistant to downy mildew and powdery mildew, and can be cultivated in the open field in the Northeast region with less or no pesticides (Ilnitskaya et al., 2023). Among them, "Shan Lan" is a representative variety of mountain grapes ×
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