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Item Population Genetics and Anastomosis Group's Geographical Distribution of Rhizoctonia solani Associated with SoybeanAutores: Abbas, Aqleem; Fang, Xiangling; Iqbal, Shehzad; Naqvi, Syed Atif Hasan; Mehmood, Yasir; Rao, Muhammad Junaid; Hassan, Zeshan; Miño Ortiz, Roberto; Baazeem, Alaa; Moustafa, Mahmoud; Alrumman, Sulaiman; Negm, SallyRhizoctonia solani is a species complex composed of many genetically diverse anastomosis groups (AG) and their subgroups. It causes economically important diseases of soybean worldwide. However, the global genetic diversity and distribution of R. solani AG associated with soybean are unknown to date. In this study, the global genetic diversity and distribution of AG associated with soybean were investigated based on rDNA-ITS sequences deposited in GenBank and published literature. The most prevalent AG, was AG-1 (40%), followed by AG-2 (19.13%), AG-4 (11.30%), AG-7 (10.43%), AG-11 (8.70%), AG-3 (5.22%) and AG-5 (3.48%). Most of the AG were reported from the USA and Brazil. Sequence analysis of internal transcribed spacers of ribosomal DNA separated AG associated with soybean into two distinct clades. Clade I corresponded to distinct subclades containing AG-2, AG-3, AG-5, AG-7 and AG-11. Clade II corresponded to subclades of AG-1 subgroups. Furthermore, AG and/or AG subgroups were in close proximity without corresponding to their geographical origin. Moreover, AG or AG subgroups within clade or subclades shared higher percentages of sequence similarities. The principal coordinate analysis also supported the phylogenetic and genetic diversity analyses. In conclusion, AG-1, AG-2, and AG-4 were the most prevalent AG in soybean. The clade or subclades corresponded to AG or AG subgroups and did not correspond to the AG’s geographical origin. The information on global genetic diversity and distribution will be helpful if novel management measures are to be developed against soybean diseases caused by R. solani.Item New insight into morphological and genetic diversity of Phlyctema vagabunda and Neofabraea kienholzii causing bull's eye rot on apple and pearAutores: Neri, Fiorella; Crucitti, Dalila; Negrini, Francesca; Pacifico, Davide; Ceredi, Gianni; Carimi, Francesco; Lolas Caneo, Mauricio; Collina, Marina; Baraldi, ElenaFungi of genera Phlyctema and Neofabraea are the causal agents of bull's eye rot, a major postharvest disease of pome fruits. To investigate their morphological and genetic diversity, isolates obtained in Italy and Chile from decayed fruit and rainwater between 2014 and 2019 were grown on two agar media, inoculated onto four fruit cultivars and compared using four marker genes. Consistent intra- and interspecies phenotypic differences were recorded among isolates identified as P. vagabunda (two main morphotypes, PvM-I and PvM-II, were distinguished) and N. kienholzii. In particular, the Chilean isolates belonging to PvM-I showed low sporulation in vitro, while isolates belonging to PvM-II showed the most abundant sporulation and also formed conidiomata deep within fruit tissue. Host cultivar influenced the disease incidence in unwounded, inoculated fruit. Cripps Pink and Golden Delicious apples favoured the formation of P. vagabunda conidiomata and macroconidia, while Granny Smith apples and/or Kaiser pears restricted sporulation of some isolates of PvM-I. Mycelial cords of P. vagabunda and N. kienholzii were consistently recorded in inoculated fruit, suggesting their possible involvement as a source of inoculum. Propagules of P. vagabunda were present in rainwater collected from apple plants from September to October in Italy. According to sequence analysis of ITS, EF-1α, TUB2 and ACT1 regions of the fungi, 12 distinct sequence types were identified, three of which were characteristic of isolates from the Southern Hemisphere. The condensed maximum-likelihood phylogenetic tree separated the 50 P. vagabunda isolates into six phylogroups, suggesting a correlation with their geographical distribution.
