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The Phormium yellow leaf phytoplasma contains two copies of the 16S rRNA gene that show sequence heterogeneity in four nucleotides. The restriction enzymes, BpmI and BsrI, can differentiate the sequence heterogeneity. The sequence similarity level between the two 16S rRNA genes in one strain is similar to the level of homology in other phytoplasma strains. The Phormium yellow leaf phytoplasma is a phytopathogenic Mollicute that is related to stolbur and German grapevine yellows phytoplasmas.

Experimental studies of the genome Nicotiana benthamiana that expresses a white clover mosaic virus strain O (WCIMV-O) 13-kDa gene which has a mutation in region 13* and possesses triple-gene block proteins reveal that 13* transgenic lines are resistant to systemic infection by WCIMV-O, -M and -J, two Potexvirus species and the Carlavirus, but not to tobacco mosaic virus of the Tobamovirus group. Nonvirian protein 13kDa is essential for the virus movement. Inhibition of virus movement leads to resistance against plant viruses with a triple gene block.

Transgenic plants that overproduce useful products project an appealing image: Grains with increased protein content, fruits and vegetables with enhanced nutritional value...flowers with deeper colors. But in trying to create [...]

The 66-kDa cytoplasmic inclusion protein of tamarillo mosaic potyvirus was purified to near homogeneity using organic solvent clarification, differential centrifugation and sucrose density gradient centrifugation. ATPase and GTPase activities were shown to co-purify with the 66-kDa protein. ATPase activity was stimulated up to fivefold in the presence of 20 pM poly(A). The Km value for ATP hydrolysis (18 µM), was minimally affected upon addition of poly(A). In contrast, the Vmax value for ATP hydrolysis was increased fivefold by the addition of poly(A). Binding of RNA by the cytoplasmic inclusion protein was demonstrated by gel electrophoresis of ultraviolet cross-linked enzyme-RNA complexes. In the absence of added NTP, complexes between the cytoplasmic inclusion protein and single-stranded RNA species formed rapidly in the pH range 3-7, but not at pH 8 or 9. Binding to single-stranded RNA was markedly decreased by the addition of NaCl (10 mM), suggesting a weak association between RNA and enzyme. The cytoplasmic inclusion protein bound single-stranded RNA or partially double-stranded RNA duplexes with single-stranded overhangs of 35 bases and 81 bases, respectively, but did not bind 16-bp blunt-ended double-stranded RNA. RNA binding occurred in the absence of NTP (ATE GTP, CTP or UTP), whereas dissociation of bound RNA occurred only in the presence of NTP. RNA duplex unwinding (helicase) activity of the enzyme was demonstrated in the presence of any of the above four NTPs using partially doublestranded RNA duplexes with 3' single-stranded overhangs. We propose that the cytoplasmic inclusion protein of tamarillo mosaic virus is an RNA helicase, which translocates in the 3' to 5' direction in an energy-dependent manner, unwinding double-stranded regions. [ABSTRACT FROM AUTHOR]