Defoliating isolates (D) produced MS
with a significantly higher length/width ratio than non-defoliating (ND) ones. These parameters were correlated using the logistic model log (y/1 − y) = 3.73L/W − 6.95, when the pathotype was regressed on length/width ratio of the propagules. Inflection point of the logistic curve corresponded to length/width = 1.86. This morphological differentiation of virulence groups could be a simple and useful tool at commercial laboratories for the assignation of the pathotype of V. dahliae isolates during routine microbiological-based diagnosis. “
“Pollen http://www.selleckchem.com/products/AZD2281(Olaparib).html is traded internationally as a source of germplasm and for pollination. Thirty-nine viruses and five viroids are known to be pollen transmitted. We investigated whether reverse transcription-polymerase chain reaction (RT-PCR) could be used to detect viruses reliably in pollen. Four extraction methods yielded nucleic acid in appropriate quantity and quality from Tobacco ringspot virus (TRSV)-infected pollen for RT-PCR amplification. One method, the RNeasy®
Plant Mini Kit was used subsequently to extract nucleic acid of amplifiable quality from nine plant species, and pollen infected with three ilarvirus and GS-1101 chemical structure two nepovirus species. A real-time TaqMan™ RT-PCR for the detection of TRSV was reliable and specific using 167 extracts of pollen from plants of Nicotiana glutinosa. The assay was highly sensitive, with extracts testing positive to a 10−6 dilution, equivalent to a single pollen grain. This demonstrated that RT-PCR methods can detect virus-infected pollen reliably, sensitively and specifically. The possible application of these RT-PCR methods to replace current quarantine procedures without compromising biosecurity is discussed. “
“During 2010–2011, a severe leaf spot disease of sweet potato (Ipomoea batatas) was found in Haikou City, Hainan province of China. The disease is characterized
with large, irregular, brown, necrotic lesions on the margin or in the centre of leaves. A species of Stemphylium was consistently recovered from pieces of symptomatic tissues on medchemexpress PDA. Based on morphological characteristics and molecular identification by rDNA-ITS gene analysis, the fungal species was identified as Stemphylium solani Weber, and its pathogenicity was confirmed by Koch’s postulates. This is the first report of leaf spot on sweet potato caused by S. solani in China. “
“Sugarcane bacilliform viruses (SCBV; genus Badnavirus) cause leaf fleck disease in sugarcane worldwide. SCBV was detected in 28 sugarcane cultivars originating from eight states of India. Eight representative SCBV isolates from five different states showed sequence variability up to 27% in the reverse transcriptase and RNase H (RT/RNase H) genetic region.