Working group session:
Germplasm and Genetic Stocks
Presentation type:
poster
Authors:
Feng, Hongjie; Du, Xiongming ; Wang, Gaskin; Wang, Sheng ; Sun, Junling ; Jia, Yinhua ; Zhao, Guohong
Presenter:
Du, Xiongming
Correspondent:
Du, Xiongming
Abstract:
The diploid Asiatic cotton is a fiber-producing species that shows a reduced level of genome complexity in comparison to the allotetraploid cotton. The fuzzless mutant is of great applicable value for identification and characterization of the genes related to fiber development in cotton. The filter arrays of cDNAs were performed to identify the differentiation expressed genes between the wild-type DPL971 and its fuzz mutant line DPL972 in Gossypium arboreumL. Some genes related to the initiation and development of the cotton fiber were isolated, and part of them have been verified by RT-PCR , QRT-PCR, immunolocalization , Southern blotting and Northern blotting techniques, And the induction of cotton ovule culture fibre branching by translate the fiber trichome genes were carried out in this study. The main results as following:
1. Some genes related to fiber initiation and development in Gossypium arboreum were identified, and seven of them, KAK(DR461366), MYB5(ES812048), TTG1(ES811600), MYB23(DR453866), CSLD3(DR459646), RHD2(DR461821), ZWI(ES791383), were highly homologous to the Arabodopsis proteins which played important roles in the initiation of the trichomes development in Arabidopsis. The 5 genes of MYB23,MYB5, TTG1, CSLD3, and RHD2had significantly different expressions in +3DPA ovules between the mutant and its wild line.
2. Two adenylyl cyclase-associated protein (CAP) homologs from wild-type and its mutant (DPL972) isolated. The Cap genes contain nine introns and an open reading frame (ORF) encoding a 471 amino acid protein. The expression of GaCAP reached the highest level in both wild-type and mutant fibers during 1 to 4 d postanthesis (DPA), then gradually declined in the mutant after 4 DPA. A polar substitution was observed at a conserved position between wild-type and mutant. This suggested that GaCAP may play a functional role during early stages of fiber development.
3. The homologs GaMYB23(a homolog of GL1), GaDEL65(a homolog of GL3),GaTTG1, GaCPC and GaTRY were identified in Gossypium arboreum. In situ analysis showed that GaMYB23, GaGL2, GaDEL65, and GaTRY were predominantly expressed in fuzz fiber, but GaTRY proteins were primarily found in undeveloped epidermal cells. G. arboretum fuzzless mutant with consistently high level GaMYB23 transcript has lost the detectable GaMYB23 promoter of GaGL2 complex, corresponding to sharply reduced transcription of GaGL2.
4. The nuclear DNA content was constant in fuzz, whereas a limited and reversible change occurred in lint after initiation. Gossypeum arboreum BRANCHLESS TRICHOMES(GaBLT) was not transcribed in fibres. The homologue of STICHEL(STI), which is essential for trichome branching, was a pseudogene in Gossypium. Targeted expression of GaBLT, Arabidopsis STI, and the cytokinesis-repressing GaSIAMESE in G. hirsutum fibre cells cultured in vitro resulted in branching.
The highly elongated single-celled cotton fiber was similar to the Arabidopsis trichome. Some key Arabidopsis trichome branching genes in Gossypium arboreum were identificated and characterized here. These findings not only lay a base for the initiation of the fiber in diploid cotton, but also deepened our understanding of the molecular basis of cotton fiber development.