Nested polymerase chain reaction
(PCR) using the phytoplasma-universal primer pairs P1/P7 followed by R16F2n/R16R2 showed the presence of phytoplasmas in 29 of 435 tested stone fruit trees. The random fragment length polymorphism (RFLP) patterns obtained after digestion of the nested PCR products separately with RsaI, AluI and SspI endonucleases indicated that selected Prunus spp. trees were infected by phytoplasmas belonging to three different subgroups of the apple proliferation group (16SrX-A, -B, -C). Nucleotide sequence analysis of 16S rDNA fragment amplified with primers R16F2n/R16R2 confirmed the PCR/Restriction Fragment Length Polymorphism (RFLP) results and revealed that phytoplasma infecting sweet cherry cv. Regina (Reg), sour cherry cv. Sokowka (Sok), apricots cv. Early Orange (EO) and AI/5, Japanese ITF2357 cell line plum cv. Ozark Premier (OzPr) and peach cv. Redhaven (RedH) was closely related to isolate European stone fruit yellows-G1 of the ‘Candidatus Phytoplasma prunorum’ (16SrX-B). Sequence and phylogenetic analyses resulted
in the highest similarity of the FK506 concentration 16S rDNA fragment of phytoplasma from nectarine cv. Super Queen (SQ) with the parallel sequence of the strain AP15 of the ‘Candidatus Phytoplasma mali’ (16SrX-A). The phytoplasma infecting sweet cherry cv. Kordia (Kord) was most similar to the PD1 strain of the ‘Candidatus Phytoplasma pyri’ (16SrX-C). This is the first report of the occurrence of ‘Ca. P. prunorum’, ‘Ca. P. mali’ and ‘Ca. P. pyri’ in naturally infected stone fruit trees in Poland. “
“Twenty-nine synthetic hexaploid wheats (SHWs) were evaluated for resistance to five isolates of Zymoseptoria tritici, a devastating wheat pathogen worldwide. The five Z. tritici isolates varied in their virulence spectra towards wheat genotypes, indicating that they have distinct set of avirulence genes. New isolate-specific resistances were identified that could be used in wheat breeding programmes. Comparing with the previous studies, the number of specific resistances identified in this 上海皓元医药股份有限公司 study
is considerable. Among 150 interactions, 78 isolate-specific resistances were identified. Interestingly, 21 wheat genotypes showed specific responses to one or more isolates tested. Of these, 12 genotypes were highly resistant to all isolates, indicating that they possess known or novel effective resistance genes. The Stb15 and Stb16/Stb17 are effective resistance genes towards isolates used in this study, indicating that the conferred resistance in these genotypes is due to the presence of either of these genes in combination or individually. Alternatively, they may carry novel broad-spectrum resistance gene(s) that their identification is of interest. Our data suggest that the presence of complete resistance to various Z. tritici isolates in SHWs justifies the need for more in-depth research to characterize the likely novel genes.