In vivo transmission of 'candidatus Phytoplasma ulmi' by Amplicephalus curtulus (Hemiptera: Cicadellidae) and its effect on ryegrass (Lolium multiflorum cv. tama).

In Chile, phytoplasmas have been reported in sugar beet, grapevine, peony, and Chilean shrubs. 'Candidatus Phytoplasma ulmi' have been detected in plants of Ugni molinae Turczanínow (Myrtaceae) and the leafhopper Amplicephalus curtulus Linnavuori & DeLong. We evaluated the possibility of phytoplasma transmission from native plants to grasses by A. curtulus and the possible effect on the plant hosts. Newly emerged adults were placed in cages with phytoplasma-infected U. molinae for 72 h (acquisition access period). These plants were then replaced by healthy ryegrasses for 20 d (latent period). They were again replaced for other healthy ryegrasses and were place in cages for 14, 7, and 1 d (inoculation access period [IAP]). After IAP, these plants were moved into different insect-free cages for 30 d, after which polymerase chain reaction (PCR) analyses were carried out. Phytoplasma-free insects on ryegrasses were considered as control treatments. Furthermore, plant height and leaf area were recorded for all treatments. After PCR, 46, 60, and 13% of the plants exposed to infected A. curtulus by 14, 7, and 1 d of IAP, respectively, were infected with 'Ca. Phytoplasma ulmi'. Similarly, plants exposed to an IAP of 14, 7, and 1 d with phytoplasma-infected leafhoppers showed a reduction in plant height of 19, 39, and 28% and leaf area of 302, 169, and 55%, respectively, in comparison to those exposed to phytoplasma-free leafhoppers. We showed that A. curtulus has the ability to transmit phytoplasma from U. molinae to ryegrasses, affecting ryegrass plant height and leaf area

Effects of bermuda grass (Cynodon dactylon cv. Coast cross) and rice hulls on growth performance of 30 day-old weaned rabbits.

Several studies have demonstrated that rabbits can be maintained on diets containing high levels of Crude Fiber (CF) when compared to other monogastric animals. In the present study, we examined the effects of rice hulls and of bermuda grass (cv. Coast cross) on the growing performance of 30 day-old weaned rabbits. Rabbits were fed one of 5 diets containing rice hulls and/or bermuda grass as fiber source at the following proportions (BG/RH) 0/17.5, 15/11, 0/29, 14.7/19.1 and 48.5/0 for diets A, B, C, D and E, respectively. Body weight gain and voluntary feed intake were measured at 30, 44, 58 and 72 days. The time necessary to attain 2 kg of live body weight was not affected by the diets. However, daily weight gain differed significantly during the first two weeks after weaning among dietary groups. Diets C and D caused a lower body weight gain, probably because of the high level of Acid Detergent Fiber (ADF) in the diet (24% and 23%). Voluntary feed intake increased with age in all treatments, but food intake was lower in treatments C and D when compared to animals receiving treatments B and E. The present results demonstrate that when rice hulls are used as fiber source, fiber must be given as ADF and not as CF because the difference between ADF and CF is enormous. Rice hull-containing diets balanced with CF give an inappropriate amount of components that seem to affect the growth performance of young animals.

A cyclophilin gene marker confirming geographical differentiation of Norway spruce populations and indicating viability response on excess soil-born salinity.

A newly identified cyclophilin-encoding cDNA clone was used to design a codominant inherited EST-PCR marker in Norway spruce. The study of the current minor polymorphism revealed a geographically structured differentiation pattern across 17 test populations, showing a slight clinal variation south-north through Europe. Based on the frequency of alleles, isolation-by-distance analysis and the Ewens-Watterson test, we conclude that a selectively neutral random-drift mutation recently occurred within the Alpine population group, thus being responsible for the genetic variation detected. Analysis of tolerant and susceptible subsets of two adjacent Bavarian spruce populations affected by soil-born NaCl pollution, revealed that the cyclophilin marker locus also confirms biased genotype frequencies. Considering an unlinked PCR marker of a ribosomal protein-encoding EST clone, deviations between pooled tolerant subsets and pooled sensitive subsets were proven to be more significant for two-locus homozygous genotypes than for each locus alone. We suggest that both loci are linked to adaptive genomic regions. Their potential to test the feasibility of marker-assisted selection of both NaCl-tolerant and drought resistant tree populations is discussed.