The accumulation of pigment in fiber related to proanthocyanidins synthesis for brown cotton

Brown cotton is a kind of naturally colored cotton. Because of less processing and little dying, it is more friendlier to environment than white cotton. For brown cotton, pigment accumulation in fiber is one of the most important characteristics. In this study, we selected a brown fiber line and a white fiber cultivar to determine the factor that affects the pigmentation in brown fiber. Accordingly, fibers were collected to verify the presence of PAs by p-dimethylaminocinnamaldehyde (DMACA) and toluidine blue O (TBO) staining. The PAs content and related genes expressions were determined. As a result, there were obvious differences on the aspect of PAs synthesis in fiber between white cotton and brown cotton. For white fiber, the PAs content reached maximum at 5 DPA, and then gradually decreased to zero. But for brown fiber, the PAs content was increased from 5 to 15 DPA stage, and reached the maximum at the 15 DPA stage, then gradually decreased from 15 to 40 DPA stage. On the contrary, in white cotton, PAs were synthesized in the whole developmental stage from 5 to 40 DPA. And PAs content in brown fiber were far more than that in white fiber, which may be the reason why the brown pigment accumulated in brown fiber.     

Up‐regulation of GhTT2‐3A in cotton fibres during secondary wall thickening results in brown fibres with improved quality

Brown cotton fibres are the most widely used naturally coloured raw materials for the eco‐friendly textile industry. Previous studies have indicated that brown fibre pigments belong to proanthocyanidins (PAs) or their derivatives, and fibre coloration is negatively associated with cotton productivity and fibre quality. To date, the molecular basis controlling the biosynthesis and accumulation of brown pigments in cotton fibres is largely unknown. In this study, based on expressional and transgenic analyses of cotton homologs of ArabidopsisPA regulator TRANSPARENT TESTA 2 (TT2) and fine‐mapping of the cotton dark‐brown fibre gene (Lc1), we show that a TT2 homolog, GhTT2‐3A, controls PA biosynthesis and brown pigmentation in cotton fibres. We observed that GhTT2‐3A activated GhbHLH130D, a homolog of ArabidopsisTT8, which in turn synergistically acted with GhTT2‐3A to activate downstream PA structural genes and PA synthesis and accumulation in cotton fibres. Furthermore, the up‐regulation of GhTT2‐3A in fibres at the secondary wall‐thickening stage resulted in brown mature fibres, and fibre quality and lint percentage were comparable to that of the white‐fibre control. The findings of this study reveal the regulatory mechanism controlling brown pigmentation in cotton fibres and demonstrate a promising biotechnological strategy to break the negative linkage between coloration and fibre quality and/or productivity.     

卵巢成熟期和退化期星斑川鲽脑垂体和下丘脑组织的转录组比较分析

为了解星斑川鲽（Starry Flounder,Platichthys stellatus）脑组织基因表达与卵巢发育调控的关系,发掘相关功能基因,研究提取卵巢成熟期和退化期星斑川鲽雌鱼脑垂体和下丘脑组织总RNA,运用HiSeq 2000高通量测序技术进行转录组测序分析。测序结果经拼接组装后共获得30640条Unigenes,Blast同源性比对显示,其中24128条Unigenes获得注释;经eggNog功能注释后29137条Unigenes序列分为26类,分别涉及信号转导、翻译机制等生理生化过程。KEGG pathway数据比对显示,卵巢成熟期涉及98种代谢途径,135条序列表达上调;卵巢退化期涉及192种代谢途径,648条序列表达上调。Unigenes表达量及表达差异分析表明在卵巢成熟期334条序列表达上调,卵巢退化期987条序列表达上调。获得功能注释的Unigene中,408条涉及生殖调控和内分泌调控,参与生殖调控的信号分子有1508条。试验采用实时定量PCR研究了涉及生殖调控和内分泌调控基因促性腺激素释放激素（GnRH）、神经激肽B（NKB）、促性腺激素（GtH）、促滤泡激素（FSH）、肿瘤转移抑制因子（Kiss）以及催乳素释放肽受体（PrRPR）在卵巢两个不同发育时期脑垂体和下丘脑的表达情况,结果表明除FSH外,其余均在卵巢退化期时期脑组织中表达升高,与转录组测序结果趋势一致。     

七星瓢虫滞育关联基因的转录组学分析

对七星瓢虫正常发育、滞育以及滞育解除的雌成虫进行RNA测序,并对筛选出来的滞育相关基因进行KEGG通路富集分析,从分子水平解析七星瓢虫滞育发机理。本研究以正常发育产卵、滞育30 d以及滞育贮存30 d后解除产卵的七星瓢虫雌成虫为研究对象,分别抽提RNA,合成c DNA,构建c DNA文库,文库检测合格后在Illummina Hiseq 2500测序仪上进行双向测序。根据测序结果,共获取unigene 82820个。采用两两比较法对正常发育组和滞育组、滞育组和滞育解除组进行差异表达分析,分别获得差异表达基因3501个和1427个。深入分析两组比对结果,将在滞育组上调且滞育解除组下调的unigene定义为滞育关联基因,共有443个基因为滞育关联基因。应用KEGG KAAS在线pathway比对分析工具对滞育关联基因进行通路富集分析,结果发现这些基因主要集中在碳水化合物代谢、脂质代谢以及信号转导等途径中。