To facilitate marker-assisted transfer of desirable genes for improvement of yield traits, we used a set of backcross recombinant
inbred lines (BRIL) derived from two elite parental lines, ‘Zhenshan97’ and ‘93-11’, to resolve a quantitative trait loci
(QTL) cluster for heading date and yield-related traits in rice. Four main-effect QTL (qHD6.1, qHD6.2, qHD7, and qHD8) and four epistatic QTL affecting heading date in the BRIL were detected in two experimental trials. The major QTL (qHD8) was confirmed in three heterogeneous inbred families (HIF) that segregated for this target region, and narrowed down to
a 20-kb segment in a large HIF-derived population. qHD8 was found to interact with qHD7 and had a pleiotropic effect responsible for heading date and yield components. To test usability of the identified QTL in
rice improvement, we further developed near-isogenic lines (NIL) containing one or more target genes by marker-assisted transfer
of ‘93-11’ alleles at qHD8, qHD7, and qHD6.1, and the GS3 gene for grain size into ‘Zhenshan97’. The pyramid line NIL(qHD8 + GS3) had higher yield potential, longer grains, and a more suitable heading date than ‘Zhenshan97’. Comparison of the NIL showed
existence of epistasis between alleles at different loci and background effect on qHD8, which are very important for pyramiding of desirable alleles at the target QTL. These results will be particularly useful
not only to understand the genetic basis of yield-related traits but also to improve the efficiency of marker-assisted selection
for favorable loci in rice breeding programs. 相似文献
The self-incompatibility of tea plant (Camellia sinensis (L.) O. Kuntze) was studied with the methods of aniline blue fluorescence assay and paraffin sections. The characteristics
of pollen tube elongation after hand pollination was analyzed in 4 tea cultivars, including ‘Keemenzhong’, ‘Longjing-changye’,
‘Fuding-dabaicha’ and ‘Yabukita’, under self-pollination and cross-pollination, respectively. Although there were some difference
among cultivars, pollen tubes elongated through the style and reach the ovary successfully at 48 h after pollination for both
cross- and self-pollen tubes in all the four cultivars of tea. Pollen tubes entered into the ovule micropyles, however, only
for cross-pollination, but not for self-pollination. Pollen tubes of selfing plants, failed in fertilizing, seemed have some
difficulties to enter the ovule. All of which indicated that the self-incompatibility of tea plant is a late-acting self-incompatibility
system (LSI) or an ovarian sterility (OS), in which the self incompatibility was due to none self pollen tube penetrating
into the ovule and no fertilization. 相似文献
The wild soybean (Glycine soja), which is the progenitor of cultivated soybean (Glycine max), is expected to offer more information about genetic variability and more useful mutants for evolutionary research and breeding
applications. Here, a total of 1,600 wild soybean samples from China were investigated for genetic variation with regard to
the soybean Kunitz trypsin inhibitor (SKTI). A new mutant SKTI, Tik, was identified. It was found to be a Tia-derived codominant allele caused by a transversion point mutation from C to G at nucleotide +171, leading to an alteration
of one codon (AAC → AAG) and a corresponding amino acid substitution (Asn → Lys) at the ninth residue. Upon examination of
this variant and others previously found in wild soybeans, it became clear that SKTI has undergone high-level evolutionary
differentiation. There were more abundant polymorphisms in the wild than in the cultivated soybean. 相似文献
Osmotic stress and endogenous hormone levels may have a role in shoot organogenesis, but a systematic study has not yet to
investigate the links. We evaluated the changes of the endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) levels
in rice (Oryza sativa L. cv. Tainan 5) callus during shoot organogenesis induced by exogenous plant growth regulator treatments or under osmotic
stress. Non-regenerable callus showed low levels of endogenous ABA and IAA, with no fluctuation in level during the period
evaluated. The addition of 100 μM ABA or 2 mM anthranilic acid (IAA precursor) into Murashige and Skoog basal induction medium
containing 10 μM 2,4-D enhanced the regeneration frequency slightly, to 5 and 35%, respectively, and their total cellular
ABA or IAA levels were increased significantly, correspondingly to the treatments. However, the regeneration frequency was
greatly increased to 80% after treatment with 0.6 M sorbitol or 100 μM ABA and 2 mM anthranilic acid combined. Both treatments
produced high levels of total cellular ABA and IAA at the callus stage, which was quickly decreased on the first day after
transfer to regeneration medium. Thus, osmotic stress-induced simultaneous accumulation of endogenous ABA and IAA is involved
in shoot regeneration in rice callus. 相似文献
With the increasing availability of microbiome 16S data, network estimation has become a useful approach to studying the interactions between microbial taxa. Network estimation on a set of variables is frequently explored using graphical models, in which the relationship between two variables is modeled via their conditional dependency given the other variables. Various methods for sparse inverse covariance estimation have been proposed to estimate graphical models in the high-dimensional setting, including graphical lasso. However, current methods do not address the compositional count nature of microbiome data, where abundances of microbial taxa are not directly measured, but are reflected by the observed counts in an error-prone manner. Adding to the challenge is that the sum of the counts within each sample, termed “sequencing depth,” is an experimental technicality that carries no biological information but can vary drastically across samples. To address these issues, we develop a new approach to network estimation, called BC-GLASSO (bias-corrected graphical lasso), which models the microbiome data using a logistic normal multinomial distribution with the sequencing depths explicitly incorporated, corrects the bias of the naive empirical covariance estimator arising from the heterogeneity in sequencing depths, and builds the inverse covariance estimator via graphical lasso. We demonstrate the advantage of BC-GLASSO over current approaches to microbial interaction network estimation under a variety of simulation scenarios. We also illustrate the efficacy of our method in an application to a human microbiome data set.
Mechanical loading can induce or antagonize the extracellular matrix (ECM) synthesis, proliferation, migration, and inflammatory responses of annulus fibrosus cells (AFCs), depending on the loading mode and level. Caveolin-1 (Cav1), the core protein of caveolae, plays an important role in cellular mechanotransduction and inflammatory responses. In the present study, we presented that AFCs demonstrated different behaviors when subjected to cyclic tensile strain (CTS) for 24 h at a magnitude of 0%, 2%, 5% and 12%, respectively. It was found that 5% CTS had positive effects on cell proliferation, migration and anabolism, while 12% CTS had the opposite effects. Besides, cells exposed to interleukin-1β stimulus exhibited an increase expression in inflammatory genes, and the expression of these genes decreased after exposure to moderate mechanical loading with 5% CTS. In addition, 5% CTS decreased the level of Cav1 and integrin β1 and exhibited anti-inflammatory effects. Moreover, the expression of integrin β1 and p-p65 increased in AFCs transfected with Cav1 plasmids. In vivo results revealed that moderate mechanical stimulation could recover the water content and morphology of the discs. In conclusion, moderate mechanical stimulation restrained Cav1-mediated signaling pathway and exhibited anti-inflammatory effects on AFCs. Together with in vivo results, this study expounds the underlying molecular mechanisms on the effect of moderate mechanical stimulation on intervertebral discs (IVDs) and may provide a new therapeutic strategy for the treatment of IVD degeneration. 相似文献
Chloroplasts are bounded by a pair of outer membranes, the envelope, that is the only permanent membrane structure of the
different types of plastids. Chloroplasts have had a long and complex evolutionary past and integration of the envelope membranes
in cellular functions is the result of this evolution. Plastid envelope membranes contain a wide diversity of lipids and terpenoid
compounds serving numerous biochemical functions and the flexibility of their biosynthetic pathways allow plants to adapt
to fluctuating environmental conditions (for instance phosphate deprivation). A large body of knowledge has been generated
by proteomic studies targeted to envelope membranes, thus revealing an unexpected complexity of this membrane system. For
instance, new transport systems for metabolites and ions have been identified in envelope membranes and new routes for the
import of chloroplast-specific proteins have been identified. The picture emerging from our present understanding of plastid
envelope membranes is that of a key player in plastid biogenesis and the co-ordinated gene expression of plastid-specific
protein (owing to chlorophyll precursors), of a major hub for integration of metabolic and ionic networks in cell metabolism,
of a flexible system that can divide, produce dynamic extensions and interact with other cell constituents. Envelope membranes
are indeed one of the most complex and dynamic system within a plant cell. In this review, we present an overview of envelope
constituents together with recent insights into the major functions fulfilled by envelope membranes and their dynamics within
plant cells.
Special Issue of Photosynthesis Research in honor of Andrew A. Benson. 相似文献