Study Of Type Specimens And Chinese Biodiversity Of Venturia

Venturia, a widespread genus in temperate and tropical regions, is mainly parasitic or saprophytic on branches, leaves, flowers and fruits of plants which belong to 24 families. Many Venturia spp. are notorious plant pathogens, such as V. inaequalis, V. pyrina and V. cerasi which separately cause the apple scab, pear scab and cherry scab. Currently,169 Venturia spp are reported and 18 of them can be found in China. However, systematic studies focused on this genus, especially the type specimens, are insufficient in our county.In this study, a comprehensive and systematic research on 359 Venturia specimens (including 78 types which belong to 54 species) from five countries was carried out based on the morphological and phylogenetic methods. Detailedly morphological descriptions and photographs, sample information, hosts, distribution and morphological comparisons were also provided. According to the results of the type specimen studies, a summary of diagnosing characteristics of Venturia has been presented as follows:1. ascomata immersed, semi-immersed or superficial, scattered or gregarious; 2. ascomata often with papillate ostiole, with or without setae; 3. paraphyses narrowly cellular, hyaline, evanescent in mature ascomata; 4. asci 8-spored, bitunicate, broadly cylindrical to obclavate, usually lacking a pedicel; 5. ascospores pale olivaceous to brown,1-septate, usually asymmetrical. Base on these characters,30 species should be removed from Venturia, i.e. V. aesculi, V. applanata, V. asterinoides, V. barbula, V. cassandrae, V. clintonii, V. compacta, V. corni, V. curviseta, V. psilotricha, V. elegantula, V. erysiphoides, V. formosa, V. gaultheriae, V. hispida, V. musae, V. nebulosa, V. occidentalis, V. parasitica, V. pezizoidea, V. pruni, V. psilotricha, V. pulchella, V. rhois, V. sabalicola, V. saccardioides, V. sacchari, V. sphaerelloidea and V. vaccinii.In addition,20 Venturia strains were isolated from 34 specimens that collected from Shangdong, Shaanxi, Henan, Liaoning, Jilin and Heilongjiang. On the basis of morphological and 2-gene multiple analyses, V. chinensis, which was collected on Lonicera praeflorens, was described as a new species of Venturia. Moreover, four unnamed species, which are different from other Venturia spp., were collected on Salix and Populus.