Genetic diversity,population structure and key phenotypic traits driving variation within soyabean (Glycine max) collection in Ghana

Soybean [Glycine max (L.) Merrill] is an important oilseed crop worldwide and it has recently become the crop of interest in Ghana. In this study, 142 soybean accessions were genotyped with 34 SSR markers and concurrently evaluated for five quantitative and two qualitative phenotypic traits. Twenty‐nine of the SSR markers were polymorphic with mean allele number of 5.3, polymorphic information content (PIC) of 0.51 and gene diversity of 0.55. Molecular analysis based on unweighted paired group arithmetic mean (UPGMA) clustering and principal coordinate analysis (PCoA) was similar in explaining the extent of diversity within the accessions. Structure analysis placed most of the accessions into two subpopulations with 18 (12.7%) as admixtures. Principal component analysis (PCA) based on phenotypic traits revealed two clusters. Both UPGMA clustering‐based SSR data and PCA from phenotypic data showed similar results. The assembled germplasm is genetically diverse with high variation in flowering and maturity period, and key yield components which could be exploited in developing superior varieties well adapted to Ghana and West Africa.     

Using Genomic Information for Altering Bolting and Flowering Behaviour of Crop Plants

Altering the phenological development of a plant is a major target of many plant breeding programs and can be exploited to achieve different outcomes. For example, in seed crops, the transition from the vegetative to the reproductive phase （flowering） should be as early as possible if unfavourable environmental conditions （drought, heat, cold） endanger seed harvest. By contrast, delayed flowering favours higher biomass production and increased yield potential by extending the grain filling phase. Flowering time is also important in crops where only vegetative parts of the plant are harvested because shoot elongation and flowering would substantially reduce yields.     

Effect of transfer time,temperature, and size on burrowing capacity of juvenile clams,Mulinia edulis,from hatchery

Studies under laboratory and field conditions have shown that juvenile Mulinia edulis clams measuring 5–15 mm are able to tolerate transfer times of over 24 hr and burrow successfully. Burrowing generally followed an asymptotic curve over time, with a rapid initial phase for smaller juveniles, which slowed over time. In laboratory conditions, at low temperatures (8°C), juvenile burrowing was initially rapid (50–70% at first 2 min). In summer temperatures (15.5°C), the burrowing capacity of three sizes of juvenile clams was tested. Size determines differences in burrowing dynamics, where juveniles of 8.9 mm shell length (SL) take longer to burrow than smaller juveniles (4.9 and 6.3 mm SL). For longer transfer times in laboratory conditions (>12 hr), burrowing was slower. The results indicate a faster burrowing rate in smaller (<10 mm) juvenile clams than in larger ones. Transfer times over 24 hr in field experiments show burrowing levels of over 50% after a 60‐min evaluation, with larger juveniles (>10 mm) requiring longer for burrowing. Based on our results, we suggest sending seeds out to grow in natural environments at SL <10 mm, temperatures below 12°C, and transfer times shorter than 12 hr. These results are valuable for improving future transfer techniques from hatchery to growout for small‐scale aquaculture of this new native species in South America.     

Resistance to powdery mildew in one Spanish barley landrace hardly resembles other previously identified wild barley resistances

Two major quantitative trait loci (QTLs) associated with resistance to powdery mildew (Blumeria graminis f. sp. hordei) were previously identified on chromosome 7H of the Spanish barley line SBCC097. The two QTLs seemed to share the same chromosomal position as the major genes mlt and Mlf, which were formerly described in Hordeum vulgare ssp. spontaneum-derived lines. In the present work, different lines that carry mlt (RS42-6*O), Mlf (RS137-28*E), or a combination of both (SI-4 and SI-6) were compared with SBCC097 to evaluate their relatedness at the phenotypic, cellular, and genetic levels. The resistance of the lines was characterised by inoculating them with a set of 27 isolates of B. graminis, which displayed a wide range of virulence. It was revealed that SBCC097 possessed a distinctive resistance spectrum. Microscopic assessment of the cytological development of the resistance response showed that SBCC097 clearly formed fewer well-established colonies and secondary hyphae than the other lines. This was confirmed by the infection type recorded after visual inspection. Genetic analyses of all five lines, based on markers flanking the QTLs derived from SBCC097, supported the macroscopic and microscopic data and pointed to the presence of a combination of novel genes or alleles in SBCC097, which may be included in the category of “intermediate-acting” genes, governing resistance mainly at the post-penetration stage.     

Rhabdocline needle cast—investigations on various Douglas fir tissue types

Douglas fir (Pseudotsuga menziesii) is one of the most important non-indigenous tree species in Germany. The species is characterized by a wide amplitude of growing conditions, and is of increasing interest, in particular from the perspective of climate change. Douglas fir is nevertheless particularly susceptible to fungal pathogens, such as Rhabdocline pseudotsugae . The aim of the present study was therefore to develop an early detection method for R. pseudotsugae based on the polymerase chain reaction (PCR). Existing molecular techniques were adapted and optimized to detect the pathogen in small sample volumes. Both healthy and infected Douglas firs were examined, with various tissue types (buds, cambial tissue, needles) and seeds tested for the presence of R. pseudotsugae. Non-infected Douglas firs did not give positive responses in the molecular analyses, but the pathogen was clearly detected in buds, cambial tissues, needles and seeds of infected trees. To date, the fungus has been considered an obligate biotrophic needle parasite. The present results provide clear evidence, however, for the existence of an endophytic stage in the life cycle of R. pseudotsugae. In contrast with previous studies, this paper investigates the dispersal of the fungus via seeds.     

Structure of Galphaq-p63RhoGEF-RhoA complex reveals a pathway for the activation of RhoA by GPCRs

The guanine nucleotide exchange factor p63RhoGEF is an effector of the heterotrimeric guanine nucleotide-binding protein (G protein) Galphaq and thereby links Galphaq-coupled receptors (GPCRs) to the activation of the small-molecular-weight G protein RhoA. We determined the crystal structure of the Galphaq-p63RhoGEF-RhoA complex, detailing the interactions of Galphaq with the Dbl and pleckstrin homology (DH and PH) domains of p63RhoGEF. These interactions involve the effector-binding site and the C-terminal region of Galphaq and appear to relieve autoinhibition of the catalytic DH domain by the PH domain. Trio, Duet, and p63RhoGEF are shown to constitute a family of Galphaq effectors that appear to activate RhoA both in vitro and in intact cells. We propose that this structure represents the crux of an ancient signal transduction pathway that is expected to be important in an array of physiological processes.     

Identification of Hedgehog pathway components by RNAi in Drosophila cultured cells

Classical genetic screens can be limited by the selectivity of mutational targeting, the complexities of anatomically based phenotypic analysis, or difficulties in subsequent gene identification. Focusing on signaling response to the secreted morphogen Hedgehog (Hh), we used RNA interference (RNAi) and a quantitative cultured cell assay to systematically screen functional roles of all kinases and phosphatases, and subsequently 43% of predicted Drosophila genes. Two gene products reported to function in Wingless (Wg) signaling were identified as Hh pathway components: a cell surface protein (Dally-like protein) required for Hh signal reception, and casein kinase 1alpha, a candidate tumor suppressor that regulates basal activities of both Hh and Wg pathways. This type of cultured cell-based functional genomics approach may be useful in the systematic analysis of other biological processes.     

Interactions between South American sea lions Otaria flavescens (Shaw) and salmon farms in southern Chile

By means of surveys in 48 salmon farms in Chile, and the analysis of fish mortality in 23, the results showed that attacks by the South American sea lion, Otaria flavescens, were periodical at a daily and seasonal scale, and because of their natural nocturnal feeding behaviour, were more frequent at night and in fall–winter seasons. The attacks varied markedly between the farms studied. No relation was found between the intensity of attacks, the distance to the nearest colony of sea lions and the population in the colony. Differences found between farms could be because of the different protective devices used, namely anti‐predator nets, acoustic harassment devices (AHDs) and fibreglass models of killer whales, and the way in which they were used. Of these devices, only the anti‐predator net achieved a permanent reduction in sea lion attacks. Both AHDs and fibreglass killer whales were inefficient in the short term.