The phylogeny and evolutionary history of the Lesion Simulating Disease (LSD) gene family in Viridiplantae.

The Lesion Simulating Disease (LSD) genes encode a family of zinc finger proteins that play a role in programmed cell death (PCD) and other biological processes, such as plant growth and photosynthesis. In the present study, we report the reconstruction of the evolutionary history of the LSD gene family in Viridiplantae. Phylogenetic analysis revealed that the monocot and eudicot genes were distributed along the phylogeny, indicating that the expansion of the family occurred prior to the diversification between these clades. Sequences encoding proteins that present one, two, or three LSD domains formed separate groups. The secondary structure of these different LSD proteins presented a similar composition, with the ß-sheets being their main component. The evolution by gene duplication was identified only to the genes that contain three LSD domains, which generated proteins with equal structure. Moreover, genes encoding proteins with one or two LSD domains evolved as single-copy genes and did not result from loss or gain in LSD domains. These results were corroborated by synteny analysis among regions containing paralogous/orthologous genes in Glycine max and Populus trichocarpa. The Ka/Ks ratio between paralogous/orthologous genes revealed that a subfunctionalization process possibly could be occurring with the LSD genes, explaining the involvement of LSD members in different biological processes, in addition to the negative regulation of PCD. This study presents important novelty in the evolutionary history of the LSD family and provides a basis for future research on individual LSD genes and their involvement in important pathway networks in plants.

The Lesion Simulating Disease (LSD) gene family as a variable in soybean response to Phakopsora pachyrhizi infection and dehydration.

The Lesion Simulating Disease (LSD) genes encode a family of zinc finger proteins that are reported to play an important role in the hypersensitive response and programmed cell death (PCD) that are caused by biotic and abiotic stresses. In the present study, 117 putative LSD family members were identified in Viridiplantae. Genes with one, two, or three conserved LSD domains were identified. Proteins with three LSD domains were highly represented in the species analyzed and were present in basal organisms. Proteins with two LSD domains were identified only in the Embryophyte clade, and proteins possessing one LSD domain were highly represented in grass species. Expression analyses of Glycine max LSD (GmLSD) genes were performed by real-time quantitative polymerase chain reaction. The results indicated that GmLSD genes are not ubiquitously expressed in soybean organs and that their expression patterns are instead organ-dependent. The expression of the majority of GmLSD genes is modulated in soybean during Phakopsora pachyrhizi infection. In addition, the expression of some GmLSD genes is modulated in plants under dehydration stress. These results suggest the involvement of GmLSD genes in the response of soybean to both biotic and abiotic stresses.

Evaluation of the impact of functional diversification on Poaceae, Brassicaceae, Fabaceae, and Pinaceae alcohol dehydrogenase enzymes.

The plant alcohol dehydrogenases (ADHs) have been intensively studied in the last years in terms of phylogeny and they have been widely used as a molecular marker. However, almost no information about their three-dimensional structure is available. Several studies point to functional diversification of the ADH, with evidence of its importance, in different organisms, in the ethanol, norepinephrine, dopamine, serotonin, and bile acid metabolism. Computational results demonstrated that in plants these enzymes are submitted to a functional diversification process, which is reinforced by experimental studies indicating distinct enzymatic functions as well as recruitment of specific genes in different tissues. The main objective of this article is to establish a correlation between the functional diversification occurring in the plant alcohol dehydrogenase family and the three-dimensional structures predicted for 17 ADH belonging to Poaceae, Brassicaceae, Fabaceae, and Pinaceae botanical families. Volume, molecular weight and surface areas are not markedly different among them. Important electrostatic and pI differences were observed with the residues responsible for some of them identified, corroborating the function diversification hypothesis. These data furnish important background information for future specific structure-function and evolutionary investigations.

Is haplogroup X present in extant South American Indians?

A total of 1,159 mitochondrial DNA samples from two Mongolian, two Siberian, and 25 South Native American populations was surveyed for the presence of the C16278T mutation, frequently found in haplogroup X. Material from 25 carriers of that mutation was then sequenced for the hypervariable segment I (HVS-I) control region, and those that still were not classifiable in classical Amerindian haplogroups were further studied. The tests involved all the control region, as well as the presence of characteristic mutations in seven coding fragments, totalling 5,760 base pairs. The results indicate that haplogroup X is not present in these samples.