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Little Leaf (little + leaf)
Selected AbstractsCharacterization of Phytoplasmas Associated With Almond Diseases in IranJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2009L. Zirak Abstract In recent years, almond witches'-broom disease has been prevalent in almond growing areas in the centre and south of Iran. Furthermore, almond trees showing different symptoms of phytoplasma diseases such as little leaf, leaf rolling, dieback of branches, rosette and yellowing were observed in the central regions of Iran. DNA isolated from symptomatic almond trees was used to amplify 16S rDNA and 16S-23S rDNA intergenic spacer (IS) fragments by nested polymerase chain reaction (PCR) using phytoplasma universal primer pairs (P1/P7, R16F2/R2, PA2F/R and NPA2F/R). Phytoplasmas were detected in symptomatic almonds in two major almond-growing regions, Isfahan and ChaharMahal-O-Bakhtiari. Restriction fragment length polymorphism analyses of nested PCR products using endonuclease enzymes HpaII and TaqI revealed that phytoplasmas associated with infected almonds are genetically different. Sequence analyses of amplified fragments of 16S rDNA and IS region indicated that the almond phytoplasmas in Iran are closely related to ,Candidatus (Ca.) Phytoplasma aurantifolia', ,Ca. Phytoplasma phoenicium', ,Ca. Phytoplasma solani' and ,Ca. Phytoplasma trifolii'. The phytoplasmas related to ,Ca. Phytoplasma aurantifolia' were more prevalent than other phytoplasmas in the central regions of Iran. [source] Basil little leaf: a new disease associated with a phytoplasma of the 16SrI (Aster Yellows) group in CubaPLANT PATHOLOGY, Issue 6 2006Y. Arocha No abstract is available for this article. [source] ,Hoja de perejil' (parsley leaf) of tomato and morrenia little leaf, two new diseases associated with a phytoplasma in BoliviaPLANT PATHOLOGY, Issue 2 2005P. Jones No abstract is available for this article. [source] Phytoplasma from little leaf disease affected sweetpotato in Western Australia: detection and phylogenyANNALS OF APPLIED BIOLOGY, Issue 1 2006F. Tairo Abstract Symptoms of leaf and stem chlorosis and plant stunting were common in sweetpotato plants (Ipomoea batatas) in farmers' fields in two widely separated locations, Kununurra and Broome, in the tropical Kimberley region in the state of Western Australia in 2003 and 2004. In the glasshouse, progeny plants developed similar symptoms characteristic of phytoplasma infection, consisting of chlorosis and a stunted, bushy appearance as a result of proliferation of axillary shoots. The same symptoms were reproduced in the African sweetpotato cv. Tanzania grafted with scions from the plant Aus1 with symptoms and in which no viruses were detected. PCR amplification with phytoplasma-specific primers and sequencing of the 16S-23S rRNA gene region from two plants with symptoms, Aus1 (Broome) and Aus142A (Kununurra), revealed highly identical sequences. Phylogenetic analysis of the 16S rRNA gene sequences obtained from previously described sweetpotato phytoplasma and inclusion of other selected phytoplasma for comparison indicated that Aus1 and Aus142A belonged to the Candidatus Phytoplasma aurantifolia species (16SrII). The 16S genes of Aus1 and Aus142A were almost identical to those of sweet potato little leaf (SPLL-V4) phytoplasma from Australia (99.3%,99.4%) but different from those of the sweetpotato phytoplasma from Taiwan (95.5%,95.6%) and Uganda (SPLL-UG, 90.0%,90.1%). Phylogenetically, Aus1, Aus142A and a phytoplasma previously described from sweetpotato in the Northern Territory of Australia formed a group distinctly different from other isolates within Ca. Phytoplasma aurantifolia species. These findings indicate that novel isolates of the 16SrII-type phytoplasma pose a potential threat to sustainable sweetpotato production in northern Australia. [source] | ||||||||||