Genetic analysis of vegetative branching in sorghum

Key message

We identified quantitative trait loci influencing plant architecture that may be valuable in breeding of optimized genotypes for sustainable food and/or cellulosic biomass production, and advancing resilience to changing climates.

Abstract

We describe a 3-year study to identify quantitative trait loci (QTLs) for vegetative branching of sorghum in a recombinant inbred line population of 161 genotypes derived from two morphologically distinct parents, S. bicolor × S. propinquum. We quantify vegetative branching based on morphological position and physiological status. Different sets of QTLs for different levels of branching were identified. QTLs discovered on chromosomes 1, 3, 7 and 8 affect multiple vegetative branching variables, suggesting that these regions may contain genes that control general axillary meristem initiation. Other regions that only influence one vegetative branching trait could contain genes that influence developmental processes contributing to divergent patterns of plant architecture. We investigate the relationship between vegetative branching patterns and dry biomass, and conclude that tillers with mature panicles and immature secondary branches each show consistent positive correlation with dry biomass. Among 19 branching-related genes from rice, eight sorghum homologs of seven rice genes are in syntenic blocks within branching-related QTL likelihood intervals. Five of these eight genes are within 700 kb of SNPs significantly associated with differences in branching in genome-wide association study of a diversity panel of 377 sorghum accessions, and three contain striking allelic variations between S. bicolor and S. propinquum that are likely to impact gene functions. Unraveling genetic determinants for vegetative branching may contribute to deterministic breeding of optimized genotypes for sustainable food and cellulosic biomass production in both optimal and marginal conditions, which are resilient to future climates that are more volatile and more stressful.     

Augmenter of liver regeneration (ALR) gene therapy attenuates CCl₄-induced liver injury and fibrosis in rats

Liver fibrosis represents a process of healing and scarring in response to chronic liver injury. Augmenter of liver regeneration (ALR) has been shown to protect hepatocytes from various toxins. The aim of this study was to investigate the effects of ALR gene therapy on liver injury and fibrosis induced by CCl(4) in rats and further explore the underlying mechanisms. Human ALR expression plasmid was delivered via the tail vein. ALR gene therapy might protect the liver from CCl(4)-induced injury and fibrogenesis by attenuating the mitochondrial dysfunction, suppressing oxidative stress, and inhibiting activation of HSCs. This report demonstrated that ALR gene therapy protected against the ATP loss, increased the activity of ATPase, decreased intrahepatic reactive oxygen species level, and down-regulated transforming growth factor-β1, platelet-derived growth factor-BB, and α-smooth muscle actin expression. Following gene transfer liver function tests were significantly improved. In brief, ALR gene therapy might be an effective therapeutic reagent for liver fibrosis with potential clinical applications.     

CDK11p46 and RPS8 associate with each other and suppress translation in a synergistic manner

CDK11p46, a 46 kDa isoform of the PITSLRE kinase family, is a key mediator of cell apoptosis, while the precise mechanism remains to be elucidated. By using His pull-down and mass spectrometry analysis, we identified the ribosomal protein S8 (RPS8), a member of the small subunit ribosome, as an interacting partner of CDK11p46. Further analysis confirmed the association of CDK11p46 and RPS8 in vitro and in vivo, and revealed that RPS8 was not a substrate of CDK11p46. Moreover, RPS8 and CDK11p46 synergize to inhibit the translation process both in cap- and internal ribosomal entry site (IRES)-dependent way, and sensitize cells to Fas ligand-induced apoptosis. Taken together, our results provide evidence for the novel role of CDK11p46 in the regulation of translation and cell apoptosis.     

Trade-offs among growth, clonal, and sexual reproduction in an invasive plant Spartina alterniflora responding to inundation and clonal integration

The purpose of this article was to study the trade-offs among vegetative growth, clonal, and sexual reproduction in an aquatic invasive weed Spartina alterniflora that experienced different inundation depths and clonal integration. Here, the rhizome connections between mother and daughter ramets were either severed or left intact. Subsequently, these clones were flooded with water levels of 0, 9, and 18 cm above the soil surface. Severing rhizomes decreased growth and clonal reproduction of daughter ramets, and increased those of mother ramets grown in shallow and deep water. The daughter ramets disconnected from mother ramets did not flower, while sexual reproduction of mother ramets was not affected by severing. Clonal integration only benefited the total rhizome length, rhizome biomass, and number of rhizomes of the whole clones in non-inundation conditions. Furthermore, growth and clonal reproduction of mother, daughter ramets, and the whole clone decreased with inundation depth, whereas sexual reproduction of mother ramets and the whole clones increased. We concluded that the trade-offs among growth, clonal, and sexual reproduction of S. alterniflora would be affected by inundation depth, but not by clonal integration.     

New triterpenoid saponins from the roots of Gypsophila perfoliata Linn

Nine new triterpenoid saponins (1–9) have been isolated from the roots of Gypsophila perfoliata Linn. Their structures were established on the basis of extensive NMR (¹H, ¹³C, HSQC and HMBC) and ESIMS studies.     

Miscellaneous terpenoid constituents of Abies nephrolepis and their moderate cytotoxic activities

Three monoterpenoids and two triterpenoids were isolated from Abiesnephrolepis together with 53 known terpenoids. The structures of the compounds were established by 1D and 2D NMR spectroscopy. The absolute configuration of 3-hydroxycamphane-2-carboxylic acid was established as (1S,2R,3S,4R) by Cu-Kα X-ray crystallography. All 58 isolates were tested for cytotoxic activity against four tumor cells viz. A549 (human lung adenocarcinoma), Colo205 (colon adenocarcinoma), QGY-7703 (human hepatoma) and THP-1 (human monocytic leukemia). α-Cadinol exhibited the best effects on A549, Colo205 and QGY-7703 with IC₅₀ values of 8.6, 8.1 and 4.6 μg/mL, respectively.