A single resistance factor to solve vineyard degeneration due to grapevine fanleaf virus

Grapevine fanleaf disease, caused by grapevine fanleaf virus (GFLV), transmitted by the soil-borne nematode Xiphinema index, provokes severe symptoms and economic losses, threatening vineyards worldwide. As no effective solution exists so far to control grapevine fanleaf disease in an environmentally friendly way, we investigated the presence of resistance to GFLV in grapevine genetic resources. We discovered that the Riesling variety displays resistance to GFLV, although it is susceptible to X. index. This resistance is determined by a single recessive factor located on grapevine chromosome 1, which we have named rgflv1. The discovery of rgflv1 paves the way for the first effective and environmentally friendly solution to control grapevine fanleaf disease through the development of new GFLV-resistant grapevine rootstocks, which was hitherto an unthinkable prospect. Moreover, rgflv1 is putatively distinct from the virus susceptibility factors already described in plants.

A single resistance factor to solve vineyard degeneration due to grapevine fanleaf virus

Grapevine fanleaf disease, caused by grapevine fanleaf virus (GFLV), transmitted by the soil-borne nematode Xiphinema index, provokes severe symptoms and economic losses, threatening vineyards worldwide. As no effective solution exists so far to control grapevine fanleaf disease in an environmentally friendly way, we investigated the presence of resistance to GFLV in grapevine genetic resources. We discovered that the Riesling variety displays resistance to GFLV, although it is susceptible to X. index. This resistance is determined by a single recessive factor located on grapevine chromosome 1, which we have named rgflv1. The discovery of rgflv1 paves the way for the first effective and environmentally friendly solution to control grapevine fanleaf disease through the development of new GFLV-resistant grapevine rootstocks, which was hitherto an unthinkable prospect. Moreover, rgflv1 is putatively distinct from the virus susceptibility factors already described in plants.

Progressive Muscular Dystrophy (Duchenne Type) (Case Report)

Clinical findings of two brothers suffering from progressive muscular dystrophy pseudohypertrophic type according to Duchenne are reported. Literatures dealing with its clinical classification, biochemical disturbances, hypotheses of the pathogenesis, management of treatment, mode of action of A.T.P. and the pedigree have been briefly reported. Progressive Muscular Dystrophy is a progressive disease affecting voluntary muscles; It is characterized by a decreased strength in the affected muscles with rapid or slow gradual progression. About 45% of the patients gave a history that at least another member of the family is affected by the disease. Pseudohypertrophic form (Duchenne type) is usually inherited as a recessive factor, often sexlinked.

What causes mating system shifts in plants? Arabidopsis lyrata as a case study

The genetic breakdown of self-incompatibility (SI) and subsequent mating system shifts to inbreeding has intrigued evolutionary geneticists for decades. Most of our knowledge is derived from interspecific comparisons between inbreeding species and their outcrossing relatives, where inferences may be confounded by secondary mutations that arose after the initial loss of SI. Here, we study an intraspecific breakdown of SI and its consequences in North American Arabidopsis lyrata to test whether: (1) particular S-locus haplotypes are associated with the loss of SI and/or the shift to inbreeding; (2) a population bottleneck may have played a role in driving the transition to inbreeding; and (3) the mutation(s) underlying the loss of SI are likely to have occurred at the S-locus. Combining multiple approaches for genotyping, we found that outcrossing populations on average harbour 5 to 9 S-locus receptor kinase (SRK) alleles, but only two, S1 and S19, are shared by most inbreeding populations. Self-compatibility (SC) behaved genetically as a recessive trait, as expected from a loss-of-function mutation. Bulked segregant analysis in SC × SI F2 individuals using deep sequencing confirmed that all SC plants were S1 homozygotes but not all S1 homozygotes were SC. This was also revealed in population surveys, where only a few S1 homozygotes were SC. Together with crossing data, this suggests that there is a recessive factor that causes SC that is physically unlinked to the S-locus. Overall, our results emphasise the value of combining classical genetics with advanced sequencing approaches to resolve long outstanding questions in evolutionary biology.

Hereditary dwarfism in yellow lupin (Lupinus luteus L)

A dwarf plant was found in the F₄ generation of a hybrid between two yellow lupin subspecies. Genetic analysis demonstrated that the dwarf grwoth is conditioned by one recessive factor which was named nanus. This factor acts pleiotroipically since it reduces the height, changes the morphological structure and some anatomical traits and reduces fertility in the dwarf plants. It is believed that in the chromosome with translocation a gene block arose in the F₄, plant. These genes acting as a compact system cause dwarfism, changes in the anatomical structure and reduce fertility.

Osteogenesis Imperfecta (Type IV) with Dental Findings in Siblings

Osteogenesis imperfecta (OI) is a hereditary disorder characterized by increased tendency for bone fractures due to high fragility. The clinical and radiological features of OI manifest in different age groups, although the disease is congenital in nature. Besides bone fragility, features like laxity of the ligaments, blue sclera, growth retardation, and scoliosis are also observed. In severe cases, respiratory distress and death have been reported. The most important oral finding in OI is the presence of yellowish-brown-coloured brittle teeth characteristic of dentinogenesis imperfecta. Genetic factors play a very important role in the pathogenesis of OI either as a dominant or recessive factor. When a child has OI, there is a 25% chance of the sibling to have the same disorder. We report two cases of OI in siblings born to parents with a history of consanguineous marriage. The clinical and radiological features of the two cases are described in detail.

Development and Characterization of Diamondback Moth Resistance to Transgenic Broccoli Expressing High Levels of Cry1C

ABSTRACT A field-collected colony of the diamondback moth, Plutella xylostella, had 31-fold resistance to Cry1C protoxin ofBacillus thuringiensis. After 24 generations of selection with Cry1C protoxin and transgenic broccoli expressing a Cry1C protein, the resistance that developed was high enough that neonates of the resistant strain could complete their entire life cycle on transgenic broccoli expressing high levels of Cry1C. After 26 generations of selection, the resistance ratios of this strain to Cry1C protoxin were 12,400- and 63,100-fold, respectively, for the neonates and second instars by a leaf dip assay. The resistance remained stable until generation 38 (G38) under continuous selection but decreased to 235-fold at G38 when selection ceased at G28. The Cry1C resistance in this strain was seen to be inherited as an autosomal and incompletely recessive factor or factors when evaluated using a leaf dip assay and recessive when evaluated using Cry1C transgenic broccoli. Saturable binding of 125I-Cry1C was found with brush border membrane vesicles (BBMV) from both susceptible and Cry1C-resistant strains. Significant differences in Cry1C binding to BBMV from the two strains were detected. BBMV from the resistant strain had about sevenfold-lower affinity for Cry1C and threefold-higher binding site concentration than BBMV from the susceptible strain. The overall Cry1C binding affinity was just 2.5-fold higher for BBMV from the susceptible strain than it was for BBMV from the resistant strain. These results suggest that reduced binding is not the major mechanism of resistance to Cry1C.