| At present, the improvement of cotton fiber quality has become the focal point of cotton breeding work in China, which is an important guarantee for sustainable development of the cotton industry. Sucrose Synthase(EC 2.4.1.13, Sus) activity and gene expression levels have direct impact on the speed of cellulose synthesis and deposition quality and then have big influence in forming of fiber length, strength characters during cotton fiber development of secondary wall thickening. Clarify the Sus complex regulatory mechanism and excellent mechanism of fiber quality during fiber development. In addition, use modern molecular marker techniques for assisted breeding, which play a very important role in breeding cotton varieties that fiber quality is excellent. In our study, a total of 216 families in Island Cotton(Gossypium barbadense L.) recombinant inbred lines(RIL) population, which construction by high yield and disease-resistant strain 5917 with disease-susceptible strain Pima-7 as well as contain of 216 Island Cotton varieties in resource(ZY) population were used for experimental materials. In 2014-2015 years, Sus activity(30 days post anthesis) and economic, agronomic traits were determinationed and investigationed with analysis the correlation relationship among them in two populations, respectively. At the same time, we used homologous cloning and bioinformatics analysis of Sus in population parent(5917, Pima-7). Activities change characteristics and gene expression patterns(0 d-35 d, days post anthesis) of parent materials in RIL population and representative varieties(Xinhai 21, Xinluzhong 36) were measured and detectioned. In addition, combination with the results of high-throughput transcriptome sequencing for verified.The main findings of this research were stated as follows:1. In two years, the mean values of variation coefficient about Sus activity were large, as well as the differences were statistically in two populations(RIL: 23.79%; ZY: 35.15%). Thedirect path coefficients between Sus activity and fiber strength were maximum in two populations. In other words, Sus activity plays the most comprehensive and direct role in the fiber strength.2. Sus activity level was proportional to the fiber strength with activities change characteristics of Sus were single peak curve in two high strength Island Cotton varieties 5917(48.2 c N·tex-1); Xinhai 21(42.3 c N·tex-1), a low strength Island Cotton variety Pima-7(37.6c N·tex-1) and also an Upland Cotton variety(Gossypium hirsutum L.) Xinluzhong 36(32.8c N·tex-1). 5917, Xinhai 21 and Pima-7 peak appear at 30 days post anthesis, Xinluzhong 36 peak appear at 25 days post anthesis.3. Correlation analysis of economic and agronomic characters turned out that amplitude of coefficient of variation about boll number and fibers elongation percentage were very big as well as coefficient of variation about yield traits were huge, coefficient of variation about fibre quality traits were little in all of 20 characters. The main internal factors that affect the lint yield were boll number and lint. The main internal factors that affect the quality traits were fiber strength and length.4. Sus g DNA sequences were obtained by homologous cloning in two parent populations.Full length of Sus1-Sus7 were 4389 bp, 3722 bp, 4397 bp, 3761 bp, 3392 bp, 5168 bp, 3972 bp, respectively. Compare 5917 Sus1 with diploid Asiatic Cotton(Gossypium arboreum L.)Ga Sus1, we could discovery that exist 9 single nucleotide polymorphism sex sites(SNP) in their coding sequence(CDS), compare Pima-7 Sus1 with Ga Sus1, we could discovery that exist 8 SNP in their CDS; compare 5917 Sus2 with Ga Sus2, we could discovery that exist 25 SNP in their CDS; compare Pima-7 Sus2 with Ga Sus2, we could discovery that exist 8 SNP in their CDS; compare 5917 Sus3 with Ga Sus3, we could discovery that exist 8 SNP in their CDS; compare Pima-7 Sus3 with Ga Sus3, we could discovery that exist 9 SNP in their CDS;compare 5917 Sus4 with Ga Sus4, we could discovery that exist 40 SNP in their CDS;compare Pima-7 Sus4 with Ga Sus4, we could discovery that exist 41 SNP in their CDS;compare 5917 Sus5 with Ga Sus5, we could discovery that exist 27 SNP in their CDS;compare Pima-7 Sus5 with Ga Sus5, we could discovery that exist 27 SNP in their CDS;compare 5917 Sus6 with Ga Sus6, we could discovery that exist 16 SNP in their CDS;compare Pima-7 Sus6 with Ga Sus6, we could discovery that exist 16 SNP in their CDS;compare 5917 Sus7 with Ga Sus7, we could discovery that exist 7 SNP in their CDS; compare Pima-7 Sus7 with Ga Sus7, we could discovery that exist 7 SNP in their CDS. Compare 5917Sus1 with Pima-7 Sus1, we could discovery that exist 1 SNP in their CDS; Compare 5917Sus2 with Pima-7 Sus2, we could discovery that exist 21 SNP in their CDS; Compare 5917Sus3 with Pima-7 Sus3, we could discovery that exist 4 SNP in their CDS; Compare 5917Sus4 with Pima-7 Sus4, we could discovery that exist 1 SNP in their CDS; Compare 5917Sus5, Sus6, Sus7 with Pima-7 Sus5, Sus6, Sus7, we could discovery that no exist SNP in their CDS.5. The transcriptome data show that, Sus1D?Sus2A?Sus3A?Sus3D?Sus4A?Sus5D?Sus6A?Sus6D, 8 of 15 Sus in tolal that high expression in allotetraploid fiber. Expression of Sus5 D, Sus2 A, Sus3 A, Sus3 D were significantly upregulated in Island Cotton Xinhai 21, their RPKM values were 5.24, 1.60, 1.51 and 1.33 fold higher than that its Upland Cotton Xinluzhong 36, respectively. While analysis by q RT-PCR method could found that except above 8 genes, there are Sus1 A and Sus8 D, which may be also associated with the development of cotton fiber. |
PDF Full Text Request