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Beneficial microorganisms can increase nutrient digestion and absorption in farmed fish. This study investigates the effects of supplemental feeding of Bacillus species isolated from the intestines of wild glass eels on the growth, survival, and gene expression of farm-raised eel larvae for 30 days after hatching. Three species of Bacillus (B. velezensis, AJBV; B. subtilis, AJBS; B. licheniformis, AJBL) without hemolytic activity were isolated, and an experiment compared the growth of eel larvae fed an artificial diet supplemented with each Bacillus species. There were no significant differences in the total length and body depth of eel larvae at 30 days after hatching in all groups. During the feeding period, 149 eels survived from the initial 1000 in the control group. On the other hand, 240, 178, and 141 eels survived in the AJBV, AJBS, and AJBL groups, respectively. However, there were no significant differences in survival rates despite the difference in the number of surviving eel larvae among the groups. In the comparison of gene expression of genes involved with growth (growth hormone, growth hormone receptor 1, insulin-like growth factor II-2) and those involved with digestive enzymes (amylase, trypsin, lipase), there were also no significant differences among the groups. Our results confirm that dietary supplementation with each of the three host-associated Bacillus does not affect the growth and survival rates of eel larvae reared on an artificial diet up to the first 30 days after hatching, nor does it significantly affect related gene expression.

Freezing limits plant growth and crop productivity, and plant species in temperate zones have the capacity to develop freezing tolerance through complex modulation of gene expression affecting various aspects of metabolism and physiology. While many components of freezing tolerance have been identified in model species under controlled laboratory conditions, little is known about the mechanisms that impart freezing tolerance in natural populations of wild species. Here, we performed a quantitative trait locus (QTL) study of acclimated freezing tolerance in seedlings of Boechera stricta , a highly adapted relative of Arabidopsis ( Arabidopsis thaliana ) native to the Rocky Mountains. A single QTL was identified that contained the gene encoding ACYL-COENZYME A:DIACYLGLYCEROL ACYLTRANSFERASE1 ( BstDGAT1 ), whose expression is highly cold responsive. The primary metabolic enzyme DGAT1 catalyzes the final step in assembly of triacylglycerol (TAG) by acyl transfer from acyl-CoA to diacylglycerol. Freezing tolerant plants showed higher DGAT1 expression during cold acclimation than more sensitive plants, and this resulted in increased accumulation of TAG in response to subsequent freezing. Levels of oligogalactolipids that are produced by SFR2 (SENSITIVE TO FREEZING2), an indispensable element of freezing tolerance in Arabidopsis, were also higher in freezing-tolerant plants. Furthermore, overexpression of AtDGAT1 led to increased freezing tolerance. We propose that DGAT1 confers freezing tolerance in plants by supporting SFR2-mediated remodeling of chloroplast membranes., (© 2018 American Society of Plant Biologists. All rights reserved.)

To broaden and delve into the genomic information of Clausena excavata , an important medicinal plant in many Asian countries, RNA sequencing (RNA-seq) analysis was performed and a total of 16,638 non-redundant unigenes (≥ 300 bp) with an average length of 755 bp were generated by de novo assembly from 17,580,456 trimmed clear reads. The functional categorization of the identified unigenes by a gene ontology (GO) term resulted in 2305 genes in the cellular component, 5577 in the biological processes, and 8056 in the molecular functions, respectively. The top sub-category in biological processes was the metabolic process with 4374 genes. Among annotated genes, 3006 were mapped to 123 metabolic pathways by the Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway analysis tool. The search for simple sequence repeats (SSRs) resulted in 845 SSRs from 749 SSR-containing unigenes and the most abundant SSR motifs was AAG/CTT with 179 occurrences. Twelve SSR markers were tested for cross transferability among five Clausena species; eight of them exhibited polymorphism. Taken together, these data provide valuable resources for genomic or genetic studies of Clausena species and other relative studies. The transcriptome shotgun assembly data have been deposited at DDBJ/EMBL/GenBank under the accession GGEM00000000., Competing Interests: Compliance with ethical standardsThe authors declare that they have no conflict of interests.

Development of chilling and freezing tolerance is complex and can be affected by photoperiod, temperature and photosynthetic performance; however, there has been limited research on the interaction of these three factors. We evaluated 108 recombinant inbred lines of Boechera stricta, derived from a cross between lines originating from Montana and Colorado, under controlled long day (LD), short-day (SD) and in an outdoor environment (OE). We measured maximum quantum yield of photosystem II, lethal temperature for 50% survival and electrolyte leakage of leaves. Our results revealed significant variation for chilling and freezing tolerance and photosynthetic performance in different environments. Using both single- and multi-trait analyses, three main-effect quantitative trait loci (QTL) were identified. QTL on linkage group (LG)3 were SD specific, whereas QTL on LG4 were found under both LD and SD. Under all conditions, QTL on LG7 were identified, but were particularly predictive for the outdoor experiment. The co-localization of photosynthetic performance and freezing tolerance effects supports these traits being co-regulated. Finally, the major QTL on LG7 is syntenic to the Arabidopsis C-repeat binding factor locus, known regulators of chilling and freezing responses in Arabidopsis thaliana and other species., (© 2014 John Wiley & Sons Ltd.)