Population Genetics of Calotropis gigantea, a Medicinal and Fiber Resource Plant, as Inferred from Microsatellite Marker Variation in two Native Countries.

Calotropis gigantea is well known for its aesthetic, medicinal, pharmacological, fodder, fuel, and fiber production potential. Unfortunately, this plant species is still undomesticated, and the genetic information available for crop improvement is limited. For this study, we sampled 21 natural populations of C. gigantea from two key areas of its natural distribution range (Bangladesh and China) and genotyped 379 individuals using nine nuclear microsatellite markers. Population genetic diversity was higher in Bangladesh than that observed in Chinese populations. Overall, a moderate level of genetic diversity was found (Na = 3.73, HE = 0.466), with most of the genetic variation detected within populations (65.49%) and substantial genetic differentiation (FST = 0.345) between the study regions. We observed a significant correlation between genetic and geographic distances (r = 0.287, P = 0.001). The Bayesian clustering, UPGMA tree, and PCoA analyses yielded three distinct genetic pools, but the number of migrants per generation was high (NM = 0.52-2.78) among them. Our analyses also revealed that some populations may have experienced recent demographic bottlenecks. Our study provides a baseline for exploitation of the genetic resources of C. gigantea in domestication and breeding programs as well as some insights into the germplasm conservation of this valuable plant.

Transcriptomic profiling of tall fescue in response to heat stress and improved thermotolerance by melatonin and 24-epibrassinolide.

BACKGROUND: Tall fescue is a widely used cool season turfgrass and relatively sensitive to high temperature. Chemical compounds like melatonin (MT) and 24-epibrassinolide (EBL) have been reported to improve plant heat stress tolerance effectively. RESULTS: In this study, we reported that MT and EBL pretreated tall fescue seedlings showed decreased reactive oxygen species (ROS), electrolyte leakage (EL) and malondialdehide (MDA), but increased chlorophyll (Chl), total protein and antioxidant enzyme activities under heat stress condition, resulting in improved plant growth. Transcriptomic profiling analysis showed that 4311 and 8395 unigenes were significantly changed after 2 h and 12 h of heat treatments, respectively. Among them, genes involved in heat stress responses, DNA, RNA and protein degradation, redox, energy metabolisms, and hormone metabolism pathways were highly induced after heat stress. Genes including FaHSFA3, FaAWPM and FaCYTC2 were significantly upregulated by both MT and EBL treatments, indicating that these genes might function as the putative target genes of MT and EBL. CONCLUSIONS: These findings indicated that heat stress caused extensively transcriptomic reprogramming of tall fescue and exogenous application of MT and EBL effectively improved thermotolerance in tall fescue.

RF magnetron sputtered (BiDy)3(FeGa)5O12:Bi2O3 composite garnet-oxide materials possessing record magneto-optic quality in the visible spectral region.

Bismuth-substituted iron garnets are considered to be the most promising magneto-optical materials because of their excellent optical transparency and very high magneto-optical figures of merit in the near-infrared spectral region. However, the practical application of garnets in the visible and short-wavelength infrared parts of spectrum is currently limited, due to their very high optical absorption (especially in sputtered films) in these spectral regions. In this paper, we identify the likely source of excess absorption observed in sputtered garnet films in comparison with epitaxial layers and demonstrate (Bi,Dy)(3)(Fe,Ga)(5)O(12): Bi(2)O(3) composites possessing record MO quality in the visible region.