西葫芦果色基因研究进展

概述了西葫芦果色基因的国内外研究进展,重点阐述了目前发现的14个西葫芦果色基因功能及相互间作用,对西葫芦果色育种亲本的选择具有一定的指导意义,为以后开展果色分子标记辅助育种提供参考。

Molecular Cloning and Expression of Carotenogenic Genes in Yellowish and Mutant Whitish Loquat (Eriobotrya japonica) Fruits

ObjectiveThe study aimed to explore the factors regulating carotenoid accumulation in flesh color. MethodA loquat mutation （red-or orange-fleshed plant emerged a bud mutation of white-flesh in trunk） was used as material; HPLC analysis of β-carotene content was conducted. ResultThe β-carotene concentration in the flesh of wild and mutant types was 60.9 and 4.6 μg/g fresh weight, respectively. According to the conserved regions of genes from rose family genome, carotenogenic gene fragments in wild and mutant types were obtained. No nucleotide variation of the carotenogenic gene fragments was observed between wild and mutant genome. Real-time quantitative polymerase chain reaction （Q-PCR） was compared and one carotenogenic gene, β-ring hydroxylase （HYB） were considerably suppressed in mature mutant loquat fruits compared with that in wild. The other six carotenogenic genes were also expressed but the expression patterns appeared to be not correlated with the amount of β-carotene concentration in wild loquat flesh. ConclusionThe mutant whitish loquat lacks the ability to synthesize β-carotene because of the transcriptional down-regulation of carotenogenic gene HYB.

Dynamic regulation of alternative splicing and chromatin structure in Drosophila gonads revealed by RNA-seq

Both transcription and post-transcriptional processes, such as alternative splicing, play crucial roles in controlling developmental programs in metazoans. Recently emerged RNA-seq method has brought our understanding of eukaryotic transcriptomes to a new level, because it can resolve both gene expression level and alternative splicing events simultaneously. To gain a better understanding of cellular differentiation in gonads, we analyzed mRNA profiles from Drosophila testes and ovaries using RNA-seq. We identified a set of genes that have sex-specific isoforms in wild-type （WT） gonads, including several transcription factors. We found that differentiation of sperms from undifferentiated germ cells induced a dramatic downregulation of RNA splicing factors. Our data confirmed that RNA splicing events are significantly more frequent in the undifferentiated cell-enriched bag of marbles （barn） mutant testis, but downregulated upon differentiation in WT testis. Consistent with this, we showed that genes required for meiosis and terminal differentiation in WT testis were mainly regulated at the transcriptional level, but not by alternative splicing. Unexpectedly, we observed an increase in expression of all families of chromatin remodeling factors and histone modifying enzymes in the undifferentiated cell-enriched bam testis. More interestingly, chromatin regulators and histone modifying enzymes with opposite enzymatic activities are coenriched in undifferentiated cells in testis, suggesting that these cells may possess dynamic chromatin architecture. Finally, our data revealed many new features of the Drosophila gonadal transcriptomes, and will lead to a more comprehensive understanding of how differential gene expression and splicing regulate gametogenesis in Drosophila. Our data provided a foundation for the systematic study of gene expression and alternative splicing in many interesting areas of germ cell biology in Droso- phila, such as the molecular basis for sexual dimorphism and the regulation of the proliferation vs terminal differentiation programs in germline stem cell lineages. The GEO accession number for the raw and analyzed RNA-seq data is GSE16960.

A large scale screen for genes （3rd chromosome） related to Wingless signaling pathway

A wing specific F 1 genetic screen was carried out using the powerful Drosophila genetic system, combined with yeast FRT/FLP and GAL4/UAS system. Form the wing phenotypes and germline clone embryonic cuticle phenotypes observed in these mutant alleles, a number of mutant alleles of known or unknown genes were isolated. Among them, fifteen mutant alleles related to Wingless signal transduction were further isolated; the arm of these mutations located were determined, and their location in the chromosome were roughly mapped.

Conditional Mutations in Drosophila

The aim of this study was to obtain unusual mutations called conditional. The mutations manifest in some, not all representatives of a species. Collections of these mutations in chromosomes X, 2, and 3 of Drosophila melanogaster were established. Sex of fly or chromosomal rearrangement was the conditions providing ＂manifestation-non manifestation＂ of these mutations. The mutations differ from the usual by a set of properties. The salient differences in addition to conditional manifestation include： manifestation dependence on the spatial arrangement of chromosomal material in the genome, parental effects （maternal or paternal） of the mutant, capacity for transferring the genome from stable to unstable state. It is suggested that conditional mutations are mutant variants of Drosophila regulatory genes contained by the large Genomic Regulatory Network of Drosophila. Thus, the genes of this category can be detected by using special breeding procedures, mutations of these genes have unusual manifestation.