铁皮石斛叶色突变体初步研究

The Preliminary Study of Leaf-color Mutant in Dendrobium officinale

为了探究铁皮石斛叶色突变机理,以铁皮石斛叶色突变体(doyo1)和正常植株(TP35)为试验材料,对其表型、叶绿素含量进行测定,并进行无参转录组测序分析。结果表明,doyo1与TP35相比,株高、茎粗均较低,生长速度较慢;叶绿素含量下降,仅为TP35的15%左右,叶绿素a/b比值(Chl a/b)显著升高。利用转录组测序技术分别从doyo1和TP35叶片中获得4.58Gb和4.90Gb有效数据(clean data),de novo组装后得到60 363条通用基因(Unigenes),其中长度大于1kb的有12 390条,N50为1 295bp。对Unigenes进行表达分析,共获得1 560条差异表达基因(DEGs)。对得到的DEGs进行生物学功能注释,获得总注释信息为1 325条。通过对注释信息进行GO和KEGG富集分析,结合定量PCR验证,结果表明,铁皮石斛叶色突变体形成的原因可能是do GLK1低水平表达和do Ftsz不表达导致叶绿体合成和分裂受阻,叶片细胞内叶绿体数量大大降低,进而叶绿素(Chl)和类胡萝卜素(Car)含量整体下降。本试验结果为研究铁皮石斛叶色突变体形成的机理提供了依据,同时,为观叶型铁皮石斛定向育种提供了参考。

To unveil the mechanism of color mutation in Dendrobium officinale Wall. ex Lindl, the wild （ TP35 ） and leaf color mutants （doy01） were used to analyse the phenotypes, chlorphyll concentrations, and sequences of transcripts. The results showed that in comparison with TP35, doy01 had lower plant height and smaller stem diameter, accompanied with slower growth rate, decreased chlorophyll concentrations（ 15% of TP35） , but increased a/b ratio（ Chl a/b）. With transcript sequencing, 4.58 Gb and 4.90 Gb clean data were generated respectively with TP35 and doyO1, from which 60 363 Unigenes were obtained by de novo assembly. Among these Unigenes, 12 930 were larger than lkb, N50 was 1, 295 bp in length. Totally 1 560 differently expressed genes （DEGs） were registered according to their expression. Among these 1 560 DEGs, 1 325 DEGs were functionally annotated. With GO and KEGG enrichment analyses of the annotated DEGs, combined with the qRT-PCR, the color change of doy01 might be attributed to the down-regulation of doGLK1 or zero-expression of doFtsz that led to defect of chlorophyll synthesis and division, the concentrations of chlorophyll and carotene were reduced remarkably. This research unveiled the mechanism of the color change of the mutant type, and laid a foundation for D. officinale breeding.